Patent Application
20180142224
This application contains a Sequence Listing in computer readable form, which is incorporated herein by reference.
The present invention relates to alpha-amylase variants having improved stability and performance, polynucleotides encoding the variants, methods of producing the variants, and methods of using the variants.
Alpha-amylases have for many years been used in laundry where is it well-known that alpha-amylases have a beneficial effect in removal of starch containing, or starch-based, stains.
WO95/26397 discloses alkaline Bacillus amylases having good wash performance measured at temperatures in the range of 30-60° C.
WO00/60060 and WO00/60058 discloses further bacterial alpha-amylases having good wash performance.
In recent years there has been a desire to reduce the temperature of the laundry in order to reduce the energy consumption. Lowering the temperature in laundry often means that the performance of the detergent composition and the enzyme is reduced and a lower wash performance is therefore obtained at low temperature.
Furthermore, detergent compositions and the storage conditions are however still harsh and a big challenge for the enzyme stability. Thus, obtaining an improved wash performance does not necessarily provide an improved stability of the enzymes. Accordingly, it is an object of the present invention to provide alpha-amylases which have improved stability in the presence of detergent and thus also provide good wash performance after storage in detergents.
Thus, the present invention provides such further improved alpha-amylase variants with improved properties compared to its parent.
The present invention relates to an alpha-amylase variant of a parent alpha-amylase, wherein said variant is a mature form of an alpha-amylase having amylase activity and wherein said variant has an improved stability and performance.
The present invention also relates to polynucleotides encoding the variants; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of producing the variants.
The present invention also relates to a composition comprising a variant according to the invention.
The present invention also relates to methods of improving the stability and performance of a parent alpha-amylase having the amino acid sequence set forth in SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13; or having at least 65%, such as at least 70%, such as at least 75%, such as at least 80%, such as at least 85%, such as at least 90%, such as at least 95%, such as at least 97%, such as at least 99% sequence identity to any one of the amino acid sequences set forth in SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13; said method optionally comprises introducing one or more modifications to said parent alpha-amylase; wherein said resulting variant has at least 65%, such as at least 70%, such as at least 75%, such as at least 80%, such as at least 85%, such as at least 90%, such as at least 95%, such as at least 97%, such as at least 99%, but less than 100%, sequence identity to the amino acid sequence as set forth in SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13, and wherein said variant has alpha-amylase activity and improved stability and improved performance as compared to said parent alpha-amylase.
The present invention also relates to use of a variant according to the invention in a cleaning process such as laundry or hard surface cleaning including dish wash and industrial cleaning.
For purposes of the present invention, the mature polypeptide disclosed in SEQ ID NO: 1 is used to determine the corresponding amino acid residue in another alpha-amylase. The amino acid sequence of another alpha-amylase is aligned with the mature polypeptide disclosed in SEQ ID NO: 1, and based on the alignment, the amino acid position number corresponding to any amino acid residue in the mature polypeptide disclosed in SEQ ID NO: 1 is determined using the Needleman-Wunsch algorithm (Needleman and Wunsch, 1970, J. Mol. Biol. 48: 443-453) as implemented in the Needle program of the EMBOSS package (EMBOSS: The European Molecular Biology Open Software Suite, Rice et al., 2000, Trends Genet. 16: 276-277), preferably version 5.0.0 or later. The parameters used are gap open penalty of 10, gap extension penalty of 0.5, and the EBLOSUM62 (EMBOSS version of BLOSUM62) substitution matrix.
Identification of the corresponding amino acid residue in another alpha-amylase may be determined by an alignment of multiple polypeptide sequences using several computer programs including, but not limited to, MUSCLE (multiple sequence comparison by log-expectation; version 3.5 or later; Edgar, 2004, Nucleic Acids Research 32: 1792-1797), MAFFT (version 6.857 or later; Katoh and Kuma, 2002, Nucleic Acids Research 30: 3059-3066; Katoh et al., 2005, Nucleic Acids Research 33: 511-518; Katoh and Toh, 2007, Bioinformatics 23: 372-374; Katoh et al., 2009, Methods in Molecular Biology 537:_39-64; Katoh and Toh, 2010, Bioinformatics 26:_1899-1900), and EMBOSS EMMA employing ClustalW (1.83 or later; Thompson et al., 1994, Nucleic Acids Research 22: 4673-4680), using their respective default parameters.
When the other enzyme has diverged from the mature polypeptide of SEQ ID NO: 1 such that traditional sequence-based comparison fails to detect their relationship (Lindahl and Elofsson, 2000, J. Mol. Biol. 295: 613-615), other pairwise sequence comparison algorithms can be used. Greater sensitivity in sequence-based searching can be attained using search programs that utilize probabilistic representations of polypeptide families (profiles) to search databases. For example, the PSI-BLAST program generates profiles through an iterative database search process and is capable of detecting remote homologs (Atschul et al., 1997, Nucleic Acids Res. 25: 3389-3402). Even greater sensitivity can be achieved if the family or superfamily for the polypeptide has one or more representatives in the protein structure databases. Programs such as GenTHREADER (Jones, 1999, J. Mol. Biol. 287: 797-815; McGuffin and Jones, 2003, Bioinformatics 19: 874-881) utilize information from a variety of sources (PSI-BLAST, secondary structure prediction, structural alignment profiles, and solvation potentials) as input to a neural network that predicts the structural fold for a query sequence. Similarly, the method of Gough et al., 2000, J. Mol. Biol. 313: 903-919, can be used to align a sequence of unknown structure with the superfamily models present in the SCOP database. These alignments can in turn be used to generate homology models for the polypeptide, and such models can be assessed for accuracy using a variety of tools developed for that purpose.
For proteins of known structure, several tools and resources are available for retrieving and generating structural alignments. For example the SCOP superfamilies of proteins have been structurally aligned, and those alignments are accessible and downloadable. Two or more protein structures can be aligned using a variety of algorithms such as the distance alignment matrix (Holm and Sander, 1998, Proteins 33: 88-96) or combinatorial extension (Shindyalov and Bourne, 1998, Protein Engineering 11: 739-747), and implementation of these algorithms can additionally be utilized to query structure databases with a structure of interest in order to discover possible structural homologs (e.g., Holm and Park, 2000, Bioinformatics 16: 566-567).
In describing the variants of the present invention, the nomenclature described below is adapted for ease of reference. The accepted IUPAC single letter or three letter amino acid abbreviation is employed.
Substitutions:
For an amino acid substitution, the following nomenclature is used: Original amino acid, position, substituted amino acid. Accordingly, the substitution of threonine at position 226 with alanine is designated as “Thr226Ala” or “T226A”. Multiple mutations are separated by addition marks (“+”), e.g., “Gly205Arg+Ser411Phe” or “G205R+S411F”, representing substitutions at positions 205 and 411 of glycine (G) with arginine (R) and serine (S) with phenylalanine (F), respectively.
Deletions:
For an amino acid deletion, the following nomenclature is used: Original amino acid, position,*. Accordingly, the deletion of glycine at position 195 is designated as “Gly195*” or “G195*”. Multiple deletions are separated by addition marks (“+”), e.g., “Gly195*+Ser411*” or “G195*+S411*”.
Insertions:
For an amino acid insertion, the following nomenclature is used: Original amino acid, position, original amino acid, inserted amino acid. Accordingly the insertion of lysine after glycine at position 195 is designated “Gly195GlyLys” or “G195GK”. An insertion of multiple amino acids is designated [Original amino acid, position, original amino acid, inserted amino acid #1, inserted amino acid #2; etc.]. For example, the insertion of lysine and alanine after glycine at position 195 is indicated as “Gly195GlyLysAla” or “G195GKA”.
In such cases the inserted amino acid residue(s) are numbered by the addition of lower case letters to the position number of the amino acid residue preceding the inserted amino acid residue(s). In the above example, the sequence would thus be:
Multiple Modifications:
Variants comprising multiple modifications are separated by addition marks (“+”), e.g., “Arg170Tyr+Gly195Glu” or “R170Y+G195E” representing a substitution of arginine and glycine at positions 170 and 195 with tyrosine and glutamic acid, respectively.
Different Modifications:
Where different modifications may be introduced at a position, the different alterations are separated by a comma, e.g., “Arg170Tyr,Glu” represents a substitution of arginine at position 170 with tyrosine or glutamic acid. Thus, “Tyr167Gly,Ala+Arg170Gly,Ala” designates the following variants:
The present invention relates to an alpha-amylase variant of a parent alpha-amylase, wherein said variant is a mature form of an alpha-amylase having amylase activity and wherein said variant has an improved stability and performance.
The inventors of the present invention have surprisingly found that variants of parent alpha-amylases according to the present invention have an improved stability as well as an improved performance, such as improved wash performance. The stability improvement has in particular been found in detergent compositions comprising a chelating agent which is considered to have a high impact on stability of alpha-amylase variants.
The term “amylase” or “alpha-amylase” as used herein, refers to an enzyme capable of catalyzing the degradation of starch. Generally, alpha-amylases (E.C. 3.2.1.1, α-D-(1->4)-glucan glucanohydrolase) are endo-acting enzymes that cleave the α-D(1->4) O-glycosidic linkages within the starch molecule in a random order.
The term “starch” as used herein, refers to any material comprised of the complex polysaccharide carbohydrates of plants, comprised of amylose and amylopectin with the formula (C6H10O5)x, wherein X can be any number. In particular, the term refers to plant-based materials, such as rice, barley, wheat, corn, rye, potato, and the like.
The term “alpha-amylase variant” as used herein, refers to a polypeptide having alpha-amylase activity comprising a modification, i.e., a substitution, insertion, and/or deletion, at one or more (e.g., several) positions. A substitution means replacement of the amino acid occupying a position with a different amino acid; a deletion means removal of the amino acid occupying a position; and an insertion means adding an amino acid adjacent to and immediately following the amino acid occupying a position, all as defined above. The variants of the present invention have at least 20%, e.g., at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 100% of the alpha-amylase activity of the amino acid sequence as set forth in SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13.
The term “alpha-amylase activity” or “amylase activity” as used herein, refers to the activity of alpha-1,4-glucan-4-glucanohydrolases, E.C. 3.2.1.1, which constitute a group of enzymes, catalyzing hydrolysis of starch and other linear and branched 1,4-glucosidic oligo- and polysaccharides. Thus, the term “alpha-amylase” as used herein, refers to an enzyme that has alpha-amylase activity (Enzyme Class; EC 3.2.1.1) that hydrolyses alpha bonds of large, alpha-linked polysaccharides, such as starch and glycogen, yielding glucose and maltose. The terms “alpha-amylase” and “amylase” may be used interchangeably and constitute the same meaning and purpose within the scope of the present invention. For purposes of the present invention, alpha-amylase activity is determined according to the procedure described in the Examples. In one embodiment, the variants of the present invention have at least 20%, e.g., at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 100% of the alpha-amylase activity of the polypeptide of SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13.
The term “parent alpha-amylase” as used herein, refers to an alpha-amylase to which an alteration is made to produce enzyme variants. The alpha-amylase having an amino acid sequence as set forth in SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13, may e.g. be a parent for the variants of the present invention. Any polypeptide having at least 65%, such as at least 70%, such as at least 75%, such as at least 80%, such as at least 85%, such at least 90%, such as at least 95%, such as at least 97%, such as at least 99%, sequence identity to any one of SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13, may also be a parent polypeptide, such as a parent alpha-amylase, for the variants of the present invention.
The parent alpha-amylase may be a fusion polypeptide or cleavable fusion polypeptide. Such fusion polypeptide may consist of a subsequence of one parent polypeptide and a subsequence of second parent polypeptide. In particular, a fusion polypeptide may consist of an A and B domain of one species of alpha-amylase and a C domain of another species of alpha-amylase, and thereby providing a parent polypeptide to generate a variant of the present invention. Techniques for producing fusion polypeptides are known in the art, and include ligating the coding sequences encoding the polypeptides so that they are in frame and that expression of the fusion polypeptide is under control of the same promoter(s) and terminator. Fusion polypeptides may also be constructed using intein technology in which fusion polypeptides are created post-translationally (Cooper et al., 1993, EMBO J. 12: 2575-2583; Dawson et al., 1994, Science 266: 776-779).
The terms “A domain”, “B domain” and “C domain” as used herein, refers to three distinct domains A, B and C, all part of the alpha-amylase structure, see, e.g., Machius et al., 1995, J. Mol. Biol. 246: 545-559. Thus, an alpha-amylase, such as a parent polypeptide and a variant according to the invention, may comprise both an A, B, and C domain. The term “domain” means a region of a polypeptide that in itself forms a distinct and independent substructure of the whole molecule. Alpha-amylases consist of a beta/alpha-8 barrel harboring the active site residues, which is denoted the A domain, a rather long loop between the beta-sheet 3 and alpha-helix 3, which is denoted the B domain (together; “A and B domain”), and a C-domain and in some cases also a carbohydrate binding domain (e.g., WO 2005/001064; Machius et al., supra).
The domains of an alpha-amylase may be determined by structure analysis such as using crystallographically techniques. An alternative method for determining the domains of an alpha-amylase is by sequence alignment of the amino acid sequence of the alpha-amylase with another alpha-amylase for which the domains have been determined. The sequence that aligns with, e.g., the C-domain sequence in the alpha-amylase for which the C-domain has been determined can be considered the C domain for the given alpha-amylase.
The term “A and B domain” as used herein, refers to two domains of an alpha-amylase taken as one unit, whereas the C domain is another unit of the alpha-amylases. Thus, the amino acid sequence of the “A and B domain” is understood as one sequence or one part of a sequence of an alpha-amylase comprising an “A and B domain” and other domains (such as the C domain). In one embodiment, the A and B domain of a parent alpha-amylase correspond to amino acids 1 to 397 of the amino acid sequence as set forth in SEQ ID NO: 1.
The term “C domain” as used herein, refers to a domain of an alpha-amylase as one unit. The “C domain” of an alpha-amylase corresponds to amino acids 398 to 483 of SEQ ID NO: 2, amino acids 401 to 486 of SEQ ID NO: 3, and 400 to 485 of SEQ ID NOs: 4 or 5.
A fusion polypeptide may further comprise a cleavage site between the two polypeptides. Upon secretion of the fusion protein, the site is cleaved releasing the two polypeptides. Examples of cleavage sites include, but are not limited to, the sites disclosed in Martin et al., 2003, J. Ind. Microbiol. Biotechnol. 3: 568-576; Svetina et al., 2000, J. Biotechnol. 76: 245-251; Rasmussen-Wilson et al., 1997, Appl. Environ. Microbiol. 63: 3488-3493; Ward et al., 1995, Biotechnology 13: 498-503; and Contreras et al., 1991, Biotechnology 9: 378-381; Eaton et al., 1986, Biochemistry 25: 505-512; Collins-Racie et al., 1995, Biotechnology 13: 982-987; Carter et al., 1989, Proteins: Structure, Function, and Genetics 6: 240-248; and Stevens, 2003, Drug Discovery World 4: 35-48.
The parent polypeptide may be obtained from microorganisms of any genus. For purposes of the present invention, the term “obtained from” as used herein in connection with a given source shall mean that the parent encoded by a polynucleotide is produced by the source or by a strain in which the polynucleotide from the source has been inserted.
It will be understood that for the aforementioned species, the invention encompasses both the perfect and imperfect states, and other taxonomic equivalents, e.g., anamorphs, regardless of the species name by which they are known. Those skilled in the art will readily recognize the identity of appropriate equivalents.
Strains of these species are readily accessible to the public in a number of culture collections, such as the American Type Culture Collection (ATCC), Deutsche Sammlung von Mikroorganismen and Zellkulturen GmbH (DSMZ), Centraalbureau Voor Schimmelcultures (CBS), and Agricultural Research Service Patent Culture Collection, Northern Regional Research Center (NRRL).
The parent polypeptide may be identified and obtained from other sources including microorganisms isolated from nature (e.g., soil, composts, water, etc.) or DNA samples obtained directly from natural materials (e.g., soil, composts, water, etc.) using the above-mentioned probes. Techniques for isolating microorganisms and DNA directly from natural habitats are well known in the art. A polynucleotide encoding a parent polypeptide may then be obtained by similarly screening a genomic DNA or cDNA library of another microorganism or mixed DNA sample. Once a polynucleotide encoding a parent polypeptide has been detected with the probe(s), the polynucleotide can be isolated or cloned by utilizing techniques that are known to those of ordinary skill in the art (see, e.g., Sambrook et al., 1989, supra). The term “alpha-amylase variant” as used herein, refers to
The term “mature form” as used herein, refers to a polypeptide in its final form following translation and any post-translational modifications, such as N-terminal processing, C-terminal truncation, glycosylation, phosphorylation, etc. Also contemplated within the term “mature polypeptide” is that the signal peptide of the polypeptide has been cleaved off e.g. during a naturel maturation process within the cell expressing the polypeptide. In one aspect, the mature polypeptide is the amino acid sequence of SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13. It is known in the art that a host cell may produce a mixture of two of more different mature polypeptides (i.e., with a different C-terminal and/or N-terminal amino acid) expressed by the same polynucleotide. It is also known in the art that different host cells process polypeptides differently, and thus, one host cell expressing a polynucleotide may produce a different mature polypeptide (e.g., having a different C-terminal and/or N-terminal amino acid) as compared to another host cell expressing the same polynucleotide. In one embodiment, a mature polypeptide comprise up to 485 amino acid residues (e.g., amino acids 1 to 485 of SEQ ID NO: 1, 4, or 5). Thus, in one embodiment, the mature polypeptide comprise up to 485 amino acid residues corresponding to the amino acid sequence set forth in SEQ ID NOs: 1, 4, or 5.
The term “Improvement Factor (IF)” as used herein, refers to a quantitative way of calculating the improvement of a particular property of a variant according to the present invention. Determination of the Improvement Factor may be according to the following formula:
Other formulas may be used to determine the Improvement Factor. The skilled person knows the presently presented formula as well as alternative ways of calculating the Improvement Factor.
According to the present invention, a value of 1.0 corresponds to the specific activity observed for the parent alpha-amylase. A value above 1.0 indicates an improvement of specific activity of the variant tested compared to the parent alpha-amylase. Accordingly, any value of >1.0 is indicative for improvement of property, such as specific activity, of the variant compared to the parent alpha-amylase.
Similarly, the term Improvement Factor may be used when measuring stability, such as thermostability, in a detergent composition of a variant. Thus, the term Improvement Factor may also be used as an indicator for stability of a variant. According to the present invention, a value of 1.0 corresponds to the stability observed for the parent alpha-amylase. A value above 1.0 indicates an improvement of stability of the variant tested compared to the parent alpha-amylase. Accordingly, any value of >1.0 is indicative for improvement in stability of the variant compared to the parent alpha-amylase.
The term “measure of stability” as used herein, refers to a measure of enzymatic stability. Such measures of stability include stability in detergents and thermostability.
The term “stability” as used herein, refers to a the residual activity of a given variant which may be determined by incubating the variant in a model detergent composition preferably comprising chelating agents such as EDTA, EDDS, EGTA, DTPA, DTMPA, MGDA or HEDP. For example, a variant may be tested in a Model A detergent composition comprising EDTA in a final concentration of 0,1%. The residual activity may then be determined after a given period of incubation time at a given temperature. E.g. by using Phadebas assays described in the Example section. Activity of the tested variant after the given time and temperature may be compared to the activity of reference incubated at 4° C. for the same time period in the same detergent composition. The lesser the difference between both treatments, the higher is the detergent stability. Similar tests may be done using other detergents containing chelators, such as DTMPA, sodium citrate and HEDP.
The term “improved storage stability” as used herein, refers to the stability of a given variant compared to the parent polypeptide, wherein residual activity is measured upon storage for a given time and temperature. Thus, the stability of a variant under storage conditions is improved when compared to a reference, such as a parent polypeptide.
In one embodiment, the variant has an improved thermostability.
The term “improved thermostability” as used herein, refers to the improved stability of a given variant compared to the parent polypeptide wherein the stability has been determined after incubation at a raised temperature for a given time period. E.g. a raised temperature may be such as 50° C. or more.
In one embodiment, the improved stability is determined by a method comprising the steps of;
In a further embodiment, the improved stability is determined by a method comprising the steps of;
calculating the residual activity of the samples as the average of activity in the samples relative to the average of the activity to frozen control samples.
The term “measure of performance” as used herein, refers to a measure of a variant's ability to perform in wash. Thus, one characteristic of a variant that is often evaluated may be wash performance. Such characteristic may be determined in a wash at 15° C. for 20 min.
The term “performance” as used herein, refers to an enzyme's ability to remove starch or starch-containing stains present on the object to be cleaned during e.g. laundry or hard surface cleaning, such as dish wash. The term “wash performance” includes cleaning in general e.g. hard surface cleaning as in dish wash, but also wash performance on textiles such as laundry, and also industrial and institutional cleaning. The wash performance may be quantified by calculating the so-called Intensity value, and results may be displayed as “Improvement Factor” (IF). Wash performance may be determined as in described in the Examples herein.
The term “Intensity value” as used herein, refers to the wash performance measured as the brightness expressed as the intensity of the light reflected from the sample when illuminated with white light. When the sample is stained the intensity of the reflected light is lower, than that of a clean sample. Therefore the intensity of the reflected light can be used to measure wash performance, where a higher intensity value correlates with higher wash performance.
Color measurements are made with a professional flatbed scanner (Kodak iQsmart, Kodak) used to capture an image of the washed textile.
To extract a value for the light intensity from the scanned images, 24-bit pixel values from the image are converted into values for red, green and blue (RGB). The intensity value (Int) is calculated by adding the RGB values together as vectors and then taking the length of the resulting vector:
Int=√{square root over (r2+g2+b2)}
The term “improved wash performance” as used herein, refers to an improvement of the wash performance of an alpha-amylase of the present invention relative to the wash performance of the parent polypeptide. Improved wash performance may be measured by comparing of the so-called Intensity value and calculating the Improvement Factor (IF). The improved wash performance is determined according to the section “Wash performance of alpha-amylases using Automatic Mechanical Stress Assay” and using model detergent J at 15° C. Other model detergents may be used, such as Model detergent A, Model detergent X or Model detergent T.
Thus, in one embodiment, the improved wash performance is determined by a method comprising the steps of;
In one embodiment, the improved wash performance is determined by a method comprising the steps of;
optionally, calculating the improvement factor (IF) as the ration of delta intensity of the alpha-amylase sample over the delta intensity of the parent alpha-amylase sample.
Some variants may have an even further improved IF for a measure of stability than for performance. Thus, in one embodiment, the variant has an Improvement Factor (IF) of >1.0 for a measure of stability and an IF of >1.0 for a measure of performance.
Particular variants may have a further improved IF for a measure of stability than for performance. Accordingly, in one embodiment, the variant has an IF of >1.5 for a measure of stability and an IF of >1.0 for a measure of performance.
Other variants may have a further improved IF for a measure of performance than for stability. Accordingly, in one embodiment, the variant has an IF of >1.5 for a measure of performance and an IF of >1.0 for a measure of stability.
In one embodiment, the variant has an IF of >1.5 for a measure of stability and an IF of >1.5 for a measure of performance.
Stability of a variant may be determined by incubating the variant in a composition, such as a detergent composition. Similar, performance of a variant, such as the wash performance, may be determined by use of a composition, such as a detergent composition. Thus, in one embodiment, the stability and performance is determined by use of a detergent composition.
The term “detergent composition” as used herein, refers to compositions intended for cleaning, such as laundry, dishwashes or other hard surfaces. The terms encompass any material/compound selected for domestic or industrial washing applications and the form of the product may be liquid, powder, or granulate. Components of a detergent composition may be enzymes, such as variants of enzymes, polymers, bleaching systems, bleach activators, crystal growth inhibitors, and bleach catalysts. Other components may be present in a detergent composition. It is within the knowledge of the skilled person to determine which specific components of the detergent composition should be included in order to be used in the present invention. In particular, the detergent compositions may comprise other enzymes than the variants of the present invention.
Thus, in one embodiment, the detergent composition comprises a protease or a variant thereof.
The term “protease” as used herein, refers to an enzyme that hydrolyses peptide bonds. It includes any enzyme belonging to the EC 3.4 enzyme group (including each of the thirteen subclasses thereof). The EC number refers to Enzyme Nomenclature 1992 from NC-IUBMB, Academic Press, San Diego, Calif., including supplements 1-5 published in Eur. J. Biochem. 1994, 223, 1-5; Eur. J. Biochem. 1995, 232, 1-6; Eur. J. Biochem. 1996, 237, 1-5; Eur. J. Biochem. 1997, 250, 1-6; and Eur. J. Biochem. 1999, 264, 610-650; respectively. The term “subtilases” refer to a sub-group of serine protease according to Siezen et al., Protein Engng. 4 (1991) 719-737 and Siezen et al. Protein Science 6 (1997) 501-523. Serine proteases or serine peptidases is a subgroup of proteases characterised by having a serine in the active site, which forms a covalent adduct with the substrate. Further the subtilases (and the serine proteases) are characterised by having two active site amino acid residues apart from the serine, namely a histidine and an aspartic acid residue. The subtilases may be divided into 6 sub-divisions, i.e. the Subtilisin family, the Thermitase family, the Proteinase K family, the Lantibiotic peptidase family, the Kexin family and the Pyrolysin family. The term “protease activity” means a proteolytic activity (EC 3.4). Proteases of the invention are endopeptidases (EC 3.4.21). The term “protease variants thereof” as used herein, refers to a variant having at least 20%, e.g., at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 100% of a parent protease.
The detergent composition may also comprise a chelator. Thus, in one embodiment, the detergent composition comprises a chelating agent.
The term “chelator” as used herein, refers to chemicals which form molecules with certain metal ions, inactivating the ions so that they cannot react with other elements. Thus, a chelator may be defined as a binding agent that suppresses chemical activity by forming chelates. Chelation is the formation or presence of two or more separate bindings between a ligand and a single central atom. The ligand may be any organic compound, a silicate or a phosphate. In the present context the term “chelating agents” comprises chelants, chelating agent, complexing agents, or sequestering agents that forms water-soluble complexes with metal ions such as calcium and magnesium. The chelate effect describes the enhanced affinity of chelating ligands for a metal ion compared to the affinity of a collection of similar non-chelating ligands for the same metal. Chelating agents having binding capacity with metal ions, in particular calcium (Ca2+) ions, and has been used widely in detergents and compositions in general for wash, such as laundry or dish wash. Chelating agents have however shown themselves to inhibit enzymatic activity. The term chelating agent is used in the present application interchangeably with “complexing agent” or “chelating agent” or “chelant”.
In one embodiment, the stability of the variant is determined after incubation in a detergent composition at 37° C. for 4 weeks. In another embodiment, the stability is determined by incubating the variant in a detergent composition at 25° C. for 2-4 weeks or longer.
Since most alpha-amylases are calcium sensitive the presence of chelating agents these may impair the enzyme activity. The calcium sensitivity of alpha-amylases can be determined by incubating a given alpha-amylase in the presence of a strong chelating agent and analyze the impact of this incubation on the activity of the alpha-amylase in question. A calcium sensitive alpha-amylase will lose a major part or all of its activity during the incubation. Chelating agent may be present in the composition in an amount from 0.0001 wt % to 20 wt %, preferably from 0.01 to 10 wt %, more preferably from 0.1 to 5 wt %.
In one embodiment, the performance is measured at a temperature of at least 15° C. in a detergent composition.
The parent alpha-amylase may be (a) a polypeptide having at least 80% sequence identity to the mature polypeptide of SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13; (b) a polypeptide encoded by a polynucleotide that hybridizes under low stringency conditions with (i) a mature polypeptide coding sequence encoding any one of SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13; (ii) the cDNA sequence thereof, or (iii) the full-length complement of (i) or (ii); or (c) a polypeptide encoded by a polynucleotide having at least 80% sequence identity to the mature polypeptide coding sequence encoding any one of SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13.
In one embodiment, the parent alpha-amylase has a sequence identity to the mature polypeptide of SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13 of at least 65%, such as at least 70%, such as at least 75%, such as at least 80%, e.g., at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100%, which have alpha-amylase activity. In one embodiment, the amino acid sequence of the parent alpha-amylase differs by up to 10 amino acids, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, from the mature polypeptide of SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13.
In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 1. In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 2. In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 3. In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 4. In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 5. In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 6. In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 7. In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 8. In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 9. In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 10. In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 11. In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 12. In another embodiment, the parent alpha-amylase comprises or consists of the amino acid sequence of SEQ ID NO: 13.
In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 1 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues. In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 2 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues. In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 3 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues. In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 4 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues. In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 5 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues. In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 6 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues. In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 7 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues. In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 8 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues. In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 9 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues. In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 10 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues. In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 11 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues. In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 12 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues. In another embodiment, the parent alpha-amylase is a fragment of the polypeptide of SEQ ID NO: 13 containing at least 475 amino acid residues, e.g., at least 480 and at least 483 amino acid residues.
In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 1. In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 2. In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 3. In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 4. In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 5. In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 6. In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 7. In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 8. In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 9. In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 10. In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 11. In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 12. In another embodiment, the parent alpha-amylase is an allelic variant of the polypeptide of SEQ ID NO: 13.
In another embodiment, the parent alpha-amylase is encoded by a polynucleotide that hybridizes under very low stringency conditions, low stringency conditions, medium stringency conditions, medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) a mature polypeptide coding sequence encoding any one of SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13, (ii) the cDNA sequence thereof, or (iii) the full-length complement of (i) or (ii) (Sambrook et al., 1989, Molecular Cloning, A Laboratory Manual, 2d edition, Cold Spring Harbor, New York).
Any of the polypeptides of SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13, or a fragment thereof, may be used to design nucleic acid probes to identify and clone DNA encoding a parent from strains of different genera or species according to methods well known in the art.
For purposes of the present invention, hybridization indicates that the polynucleotide hybridizes to a labeled nucleic acid probe corresponding to (i) the mature polypeptide coding sequence encoding any one of SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13; (ii) the cDNA sequence thereof; (iii) the full-length complement thereof; or (iv) a subsequence thereof; under very low to very high stringency conditions. Molecules to which the nucleic acid probe hybridizes under these conditions can be detected using, for example, X-ray film or any other detection means known in the art.
The term “very high stringency conditions” means for probes of at least 100 nucleotides in length, prehybridization and hybridization at 42° C. in 5×SSPE, 0.3% SDS, 200 micrograms/ml sheared and denatured salmon sperm DNA, and 50% formamide, following standard Southern blotting procedures for 12 to 24 hours. The carrier material is finally washed three times each for 15 minutes using 2×SSC, 0.2% SDS at 70° C.
The term “high stringency conditions” means for probes of at least 100 nucleotides in length, prehybridization and hybridization at 42° C. in 5×SSPE, 0.3% SDS, 200 micrograms/ml sheared and denatured salmon sperm DNA, and 50% formamide, following standard Southern blotting procedures for 12 to 24 hours. The carrier material is finally washed three times each for 15 minutes using 2×SSC, 0.2% SDS at 65° C.
The term “medium-high stringency conditions” means for probes of at least 100 nucleotides in length, prehybridization and hybridization at 42° C. in 5×SSPE, 0.3% SDS, 200 micrograms/ml sheared and denatured salmon sperm DNA, and 35% formamide, following standard Southern blotting procedures for 12 to 24 hours. The carrier material is finally washed three times each for 15 minutes using 2×SSC, 0.2% SDS at 60° C.
The term “medium stringency conditions” means for probes of at least 100 nucleotides in length, prehybridization and hybridization at 42° C. in 5×SSPE, 0.3% SDS, 200 micrograms/ml sheared and denatured salmon sperm DNA, and 35% formamide, following standard Southern blotting procedures for 12 to 24 hours. The carrier material is finally washed three times each for 15 minutes using 2×SSC, 0.2% SDS at 55° C.
The term “low-medium stringency conditions” as used herein, refers to the conditions where probes of at least 100 nucleotides in length, prehybridization and hybridization at 42° C. in 5×SSPE, 0.3% SDS, 200 micrograms/ml sheared and denatured salmon sperm DNA, and 35% formamide, following standard Southern blotting procedures for 12 to 24 hours. The carrier material is finally washed three times each for 15 minutes using 2×SSC, 0.2% SDS at 45° C.
The term “low stringency conditions” as used herein, refers to the conditions where probes of at least 100 nucleotides in length, prehybridization and hybridization at 42° C. in 5×SSPE, 0.3% SDS, 200 micrograms/ml sheared and denatured salmon sperm DNA, and 35% formamide, following standard Southern blotting procedures for 12 to 24 hours. The carrier material is finally washed three times each for 15 minutes using 2×SSC, 0.2% SDS at 40° C.
The term “very low stringency conditions” means for probes of at least 100 nucleotides in length, prehybridization and hybridization at 42° C. in 5×SSPE, 0.3% SDS, 200 micrograms/ml sheared and denatured salmon sperm DNA, and 25% formamide, following standard Southern blotting procedures for 12 to 24 hours. The carrier material is finally washed three times each for 15 minutes using 2×SSC, 0.2% SDS at 45° C.
In one embodiment, the parent alpha-amylase comprises or consists of an amino acid sequence having at least 65%, such as at least 70%, such as at least 75%, such as at least 80%, such as at least 85%, such as at least 90%, such as at least 95%, such as at least 97%, such as at least 99%, or 100% sequence identity to any one of the amino acid sequences set forth in SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13.
In a particular embodiment, the parent alpha-amylase is a fragment of the amino acid sequence set forth in SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13, wherein the fragment has alpha-amylase activity.
The present invention relates in particular to variants of parent alpha-amylases. Thus, in one embodiment, the variant has at least 65%, such as at least 70%, such as at least 75%, such as at least 80%, such as at least 85%, such as at least 90%, such as at least 95%, such as at least 97%, such as at least 99%, but less than 100% sequence identity to said parent alpha-amylase.
Accordingly, the variant has at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, such as at least 96%, at least 97%, at least 98%, or at least 99%, but less than 100%, sequence identity to the mature polypeptide of SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13.
In one embodiment, the one or more modification(s) is a deletion, insertion and/or substitution.
The term “modification” as used herein, refers to both substitutions and deletions of amino acid within the amino acid sequence of a polypeptide. The terms “alteration” and “modification” may be used interchangeably herein. This should not be understood as any limitation and thus, the terms constitute the same meaning and purpose unless explicitly stated otherwise.
The terms “deletion”, “insertion”, and “substitution” as used herein, has the same meaning and purpose as described herein above. Furthermore, the skilled person within the art knows how to introduce such modifications to a parent alpha-amylase and thereby providing a variant of a parent alpha-amylase.
In one embodiment, the number of modifications in the variants of the present invention is 1 to 30, e.g., 1 to 20, 1 to 10, and 1 to 5, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 modifications.
The variants may further comprise one or more additional alterations at one or more (e.g., several) other positions.
The amino acid changes may be of a minor nature, that is conservative amino acid substitutions or insertions that do not significantly affect the folding and/or activity of the protein; small deletions, typically of 1-30 amino acids; small amino- or carboxyl-terminal extensions, such as an amino-terminal methionine residue; a small linker peptide of up to 20-25 residues; or a small extension that facilitates purification by changing net charge or another function, such as a poly-histidine tract, an antigenic epitope or a binding domain.
Examples of conservative substitutions are within the groups of basic amino acids (arginine, lysine and histidine), acidic amino acids (glutamic acid and aspartic acid), polar amino acids (glutamine and asparagine), hydrophobic amino acids (leucine, isoleucine and valine), aromatic amino acids (phenylalanine, tryptophan and tyrosine), and small amino acids (glycine, alanine, serine, threonine and methionine). Amino acid substitutions that do not generally alter specific activity are known in the art and are described, for example, by H. Neurath and R. L. Hill, 1979, In, The Proteins, Academic Press, New York. Common substitutions are Ala/Ser, Val/Ile, Asp/Glu, Thr/Ser, Ala/Gly, Ala/Thr, Ser/Asn, Ala/Val, Ser/Gly, Tyr/Phe, Ala/Pro, Lys/Arg, Asp/Asn, Leu/Ile, Leu/Val, Ala/Glu, and Asp/Gly.
Alternatively, the amino acid changes are of such a nature that the physico-chemical properties of the polypeptides are altered. For example, amino acid changes may improve the thermal stability of the polypeptide, alter the substrate specificity, change the pH optimum, and the like.
Essential amino acids in a polypeptide can be identified according to procedures known in the art, such as site-directed mutagenesis or alanine-scanning mutagenesis (Cunningham and Wells, 1989, Science 244: 1081-1085). In the latter technique, single alanine mutations are introduced at every residue in the molecule, and the resultant mutant molecules are tested for alpha-amylase activity to identify amino acid residues that are critical to the activity of the molecule. See also, Hilton et al., 1996, J. Biol. Chem. 271: 4699-4708. The active site of the enzyme or other biological interaction can also be determined by physical analysis of structure, as determined by such techniques as nuclear magnetic resonance, crystallography, electron diffraction, or photoaffinity labeling, in conjunction with mutation of putative contact site amino acids. See, for example, de Vos et al., 1992, Science 255: 306-312; Smith et al., 1992, J. Mol. Biol. 224: 899-904; Wlodaver et al., 1992, FEBS Lett. 309: 59-64. The identity of essential amino acids can also be inferred from an alignment with a related polypeptide
The present invention also relates to methods for obtaining a variant having alpha-amylase activity, comprising: (a) introducing into a parent alpha-amylase a modification at one or more (e.g., several) positions, wherein the variant has alpha-amylase activity; and (b) recovering the variant.
The variants may be prepared using any mutagenesis procedure known in the art, such as site-directed mutagenesis, synthetic gene construction, semi-synthetic gene construction, random mutagenesis, shuffling, etc.
Site-directed mutagenesis is a technique in which one or more (e.g., several) mutations are introduced at one or more defined sites in a polynucleotide encoding the parent.
Site-directed mutagenesis can be accomplished in vitro by PCR involving the use of oligonucleotide primers containing the desired mutation. Site-directed mutagenesis can also be performed in vitro by cassette mutagenesis involving the cleavage by a restriction enzyme at a site in the plasmid comprising a polynucleotide encoding the parent and subsequent ligation of an oligonucleotide containing the mutation in the polynucleotide. Usually the restriction enzyme that digests the plasmid and the oligonucleotide is the same, permitting sticky ends of the plasmid and the insert to ligate to one another. See, e.g., Scherer and Davis, 1979, Proc. Natl. Acad. Sci. USA 76: 4949-4955; and Barton et al., 1990, Nucleic Acids Res. 18: 7349-4966.
Site-directed mutagenesis can also be accomplished in vivo by methods known in the art. See, e.g., U.S. Patent Application Publication No. 2004/0171154; Storici et al., 2001, Nature Biotechnol. 19: 773-776; Kren et al., 1998, Nat. Med. 4: 285-290; and Calissano and Macino, 1996, Fungal Genet. Newslett. 43: 15-16.
Any site-directed mutagenesis procedure can be used in the present invention. There are many commercial kits available that can be used to prepare variants.
Synthetic gene construction entails in vitro synthesis of a designed polynucleotide molecule to encode a polypeptide of interest. Gene synthesis can be performed utilizing a number of techniques, such as the multiplex microchip-based technology described by Tian et al. (2004, Nature 432: 1050-1054) and similar technologies wherein oligonucleotides are synthesized and assembled upon photo-programmable microfluidic chips.
Single or multiple amino acid substitutions, deletions, and/or insertions can be made and tested using known methods of mutagenesis, recombination, and/or shuffling, followed by a relevant screening procedure, such as those disclosed by Reidhaar-Olson and Sauer, 1988, Science 241: 53-57; Bowie and Sauer, 1989, Proc. Natl. Acad. Sci. USA 86: 2152-2156; WO 95/17413; or WO 95/22625. Other methods that can be used include error-prone PCR, phage display (e.g., Lowman et al., 1991, Biochemistry 30: 10832-10837; U.S. Pat. No. 5,223,409; WO 92/06204) and region-directed mutagenesis (Derbyshire et al., 1986, Gene 46: 145; Ner et al., 1988, DNA 7: 127).
Mutagenesis/shuffling methods can be combined with high-throughput, automated screening methods to detect activity of cloned, mutagenized polypeptides expressed by host cells (Ness et al., 1999, Nature Biotechnology 17: 893-896). Mutagenized DNA molecules that encode active polypeptides can be recovered from the host cells and rapidly sequenced using standard methods in the art. These methods allow the rapid determination of the importance of individual amino acid residues in a polypeptide.
Semi-synthetic gene construction is accomplished by combining aspects of synthetic gene construction, and/or site-directed mutagenesis, and/or random mutagenesis, and/or shuffling. Semi-synthetic construction is typified by a process utilizing polynucleotide fragments that are synthesized, in combination with PCR techniques. Defined regions of genes may thus be synthesized de novo, while other regions may be amplified using site-specific mutagenic primers, while yet other regions may be subjected to error-prone PCR or non-error prone PCR amplification. Polynucleotide subsequences may then be shuffled.
The present invention also relates to polynucleotides encoding a variant of the present invention. Thus, in one aspect, the present invention relates to polynucleotides encoding a variant which is a mature form of an alpha-amylase having amylase activity and wherein said variant has an improved stability and performance.
The term “polynucleotides encoding” as used herein, refers to a polynucleotide that encodes a mature polypeptide having alpha-amylase having alpha-amylase activity.
In one embodiment, the polynucleotide encoding a variant according to the present invention as at least 80%, such as at least 85%, such as at least 90%, such as at least 95%, such as at least 96%, such as at least 97%, such as at least 98%, such as at least 99% but less than 100% sequence identity to the polynucleotide encoding any one of the amino acid sequences set forth in SEQ ID NOs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13.
The present invention also relates to nucleic acid constructs comprising a polynucleotide encoding a variant of the present invention operably linked to one or more control sequences that direct the expression of the coding sequence in a suitable host cell under conditions compatible with the control sequences. Thus, in one aspect, the present invention relates to nucleic acid constructs comprising a polynucleotide encoding a variant which is a mature form of an alpha-amylase having amylase activity and wherein said variant has an improved stability and performance, wherein the polynucleotide is operably linked to one or more control sequences that direct the expression of the coding sequence in a suitable host cell under conditions compatible with the control sequences.
The term “nucleic acid construct” as used herein, refers to a nucleic acid molecule, either single- or double-stranded, which is isolated from a naturally occurring gene or is modified to contain segments of nucleic acids in a manner that would not otherwise exist in nature or which is synthetic, which comprises one or more control sequences. A nucleic acid encompasses DNA, RNA, heteroduplexes, and synthetic molecules capable of encoding a polypeptide. Nucleic acids may be single stranded or double stranded, and may be chemical modifications. The terms “nucleic acids” and “polynucleotide” may be used interchangeably, but constitute the same meaning and purpose. Because the genetic code id degenerate, more than one codon may be used to encode a particular amino acid, and the present compositions and methods encompass nucleotide sequences which encode a particular amino acid sequence. Unless otherwise indicated by context, nucleic acids are written left to right in 5′ to 3′ orientation; amino acids sequences are written left to right in amino to carboxy orientation, respectively.
The term “operably linked” as used herein, refers to a configuration in which a control sequence is placed at an appropriate position relative to the coding sequence of a polynucleotide such that the control sequence directs expression of the coding sequence.
The polynucleotide may be manipulated in a variety of ways to provide for expression of a variant. Manipulation of the polynucleotide prior to its insertion into a vector may be desirable or necessary depending on the expression vector. The techniques for modifying polynucleotides utilizing recombinant DNA methods are well known in the art.
The control sequence may be a promoter, a polynucleotide which is recognized by a host cell for expression of the polynucleotide. The promoter comprises transcriptional control sequences that mediate the expression of the variant. The promoter may be any polynucleotide that shows transcriptional activity in the host cell including mutant, truncated, and hybrid promoters, and may be obtained from genes encoding extracellular or intracellular polypeptides either homologous or heterologous to the host cell.
The term “promoter” as used herein, refers to a regulatory sequence that is involved in binding RNA polymerase to initiate transcription of a gene, and may be an inducible promoter or a constitutive promoter. The skilled person would know of possible promoters that are suitable for the particular nucleic acid construct used.
The present invention also relates to recombinant expression vectors comprising a polynucleotide encoding a variant of the present invention, a promoter, and transcriptional and translational stop signals. Thus, in one aspect, the present invention relates to recombinant expression vectors comprising a polynucleotide encoding a variant which is a mature form of an alpha-amylase having amylase activity and wherein said variant has an improved stability and performance, a promoter, and transcriptional and translational stop signals.
The term “expression vector” as used herein, refers to a linear or circular DNA molecule that comprises a polynucleotide encoding a variant and is operably linked to control sequences that provide for its expression.
The various nucleotide and control sequences may be joined together to produce a recombinant expression vector that may include one or more convenient restriction sites to allow for insertion or substitution of the polynucleotide encoding the variant at such sites. Alternatively, the polynucleotide may be expressed by inserting the polynucleotide or a nucleic acid construct comprising the polynucleotide into an appropriate vector for expression. In creating the expression vector, the coding sequence is located in the vector so that the coding sequence is operably linked with the appropriate control sequences for expression.
The recombinant expression vector may be any vector (e.g., a plasmid or virus) that can be conveniently subjected to recombinant DNA procedures and can bring about expression of the polynucleotide. The choice of the vector will typically depend on the compatibility of the vector with the host cell into which the vector is to be introduced. The vector may be a linear or closed circular plasmid.
The vector may be an autonomously replicating vector, i.e., a vector that exists as an extrachromosomal entity, the replication of which is independent of chromosomal replication, e.g., a plasmid, an extrachromosomal element, a minichromosome, or an artificial chromosome. The vector may contain any means for assuring self-replication. Alternatively, the vector may be one that, when introduced into the host cell, is integrated into the genome and replicated together with the chromosome(s) into which it has been integrated. Furthermore, a single vector or plasmid or two or more vectors or plasmids that together contain the total DNA to be introduced into the genome of the host cell, or a transposon, may be used.
The vector preferably contains one or more selectable markers that permit easy selection of transformed, transfected, transduced, or the like cells. A selectable marker is a gene the product of which provides for biocide or viral resistance, resistance to heavy metals, prototrophy to auxotrophs, and the like.
The skilled person would know which expression vector is the most suitable for specific expression systems. Thus, the present invention is not limited to any specific expression vector, but any expression vector comprising the polynucleotide encoding a variant according to the invention is considered part of the present invention.
The present invention also relates to recombinant host cells, comprising a polynucleotide encoding a variant of the present invention operably linked to one or more control sequences that direct the production of a variant of the present invention. Thus, in one aspect, the present invention relates to recombinant host cells, comprising a polynucleotide encoding a variant which is a mature form of an alpha-amylase having amylase activity and wherein said variant has an improved stability and performance, a nucleic acid construct comprising a polynucleotide encoding a variant which is a mature form of an alpha-amylase having amylase activity and wherein said variant has an improved stability and performance, wherein the polynucleotide is operably linked to one or more control sequences that direct the expression of the coding sequence in a suitable host cell under conditions compatible with the control sequences, or an expression vector comprising a polynucleotide encoding a variant which is a mature form of an alpha-amylase having amylase activity and wherein said variant has an improved stability and performance, a promoter, and transcriptional and translational stop signals.
The term “host cell” as used herein, refers to any cell type that is susceptible to transformation, transfection, transduction, or the like with a nucleic acid construct or expression vector comprising a polynucleotide of the present invention. The term “host cell” encompasses any progeny of a parent cell that is not identical to the parent cell due to mutations that occur during replication.
A construct or vector comprising a polynucleotide is introduced into a host cell so that the construct or vector is maintained as a chromosomal integrant or as a self-replicating extra-chromosomal vector as described earlier. The choice of a host cell will to a large extent depend upon the gene encoding the variant and its source.
The host cell may be any cell useful in the recombinant production of a variant, e.g., a prokaryote or a eukaryote.
The prokaryotic host cell may be any Gram-positive or Gram-negative bacterium. Gram-positive bacteria include, but are not limited to, Bacillus, Clostridium, Enterococcus, Geobacillus, Lactobacillus, Lactococcus, Oceanobacillus, Staphylococcus, Streptococcus, and Streptomyces. Gram-negative bacteria include, but are not limited to, Campylobacter, E. coli, Flavobacterium, Fusobacterium, Helicobacter, Ilyobacter, Neisseria, Pseudomonas, Salmonella, and Ureaplasma.
The present invention also relates to methods of producing a variant, comprising: (a) cultivating a host cell of the present invention under conditions suitable for expression of the variant; and (b) recovering the variant. Thus, in one aspect, the present invention relates to a method of producing a variant which is a mature form of an alpha-amylase having amylase activity and wherein said variant has an improved stability and performance, comprising: (a) cultivating a host cell according to the present invention under conditions suitable for expression of the variant; and (b) recovering the variant.
The host cells are cultivated in a nutrient medium suitable for production of the variant using methods known in the art. For example, the cell may be cultivated by shake flask cultivation, or small-scale or large-scale fermentation (including continuous, batch, fed-batch, or solid state fermentations) in laboratory or industrial fermentors performed in a suitable medium and under conditions allowing the variant to be expressed and/or isolated. The cultivation takes place in a suitable nutrient medium comprising carbon and nitrogen sources and inorganic salts, using procedures known in the art. Suitable media are available from commercial suppliers or may be prepared according to published compositions (e.g., in catalogues of the American Type Culture Collection). If the variant is secreted into the nutrient medium, the variant can be recovered directly from the medium. If the variant is not secreted, it can be recovered from cell lysates.
The variant may be detected using methods known in the art that are specific for the polypeptides having alpha-amylase activity. These detection methods include, but are not limited to, use of specific antibodies, formation of an enzyme product, or disappearance of an enzyme substrate. For example, an enzyme assay may be used to determine the activity of the variant.
The variant may be recovered using methods known in the art. For example, the variant may be recovered from the nutrient medium by conventional procedures including, but not limited to, collection, centrifugation, filtration, extraction, spray-drying, evaporation, or precipitation.
The variant may be purified by a variety of procedures known in the art including, but not limited to, chromatography (e.g., ion exchange, affinity, hydrophobic, chromatofocusing, and size exclusion), electrophoretic procedures (e.g., preparative isoelectric focusing), differential solubility (e.g., ammonium sulfate precipitation), SDS-PAGE, or extraction (see, e.g., Protein Purification, Janson and Ryden, editors, VCH Publishers, New York, 1989) to obtain substantially pure variants.
In an alternative aspect, the variant is not recovered, but rather a host cell of the present invention expressing the variant is used as a source of the variant.
The variants may be prepared using any mutagenesis procedure known in the art, such as site-directed mutagenesis, synthetic gene construction, semi-synthetic gene construction, random mutagenesis, shuffling, etc.
Site-directed mutagenesis is a technique in which one or more (e.g., several) mutations are introduced at one or more defined sites in a polynucleotide encoding the parent.
Site-directed mutagenesis can be accomplished in vitro by PCR involving the use of oligonucleotide primers containing the desired mutation. Site-directed mutagenesis can also be performed in vitro by cassette mutagenesis involving the cleavage by a restriction enzyme at a site in the plasmid comprising a polynucleotide encoding the parent polypeptide and subsequent ligation of an oligonucleotide containing the mutation in the polynucleotide. Usually the restriction enzyme that digests the plasmid and the oligonucleotide is the same, permitting sticky ends of the plasmid and the insert to ligate to one another. See, e.g., Scherer and Davis, 1979, Proc. Natl. Acad. Sci. USA 76: 4949-4955; and Barton et al., 1990, Nucleic Acids Res. 18: 7349-4966.
Site-directed mutagenesis can also be accomplished in vivo by methods known in the art. See, e.g., U.S. Patent Application Publication No. 2004/0171154; Storici et al., 2001, Nature Biotechnol. 19: 773-776; Kren et al., 1998, Nat. Med. 4: 285-290; and Calissano and Macino, 1996, Fungal Genet. Newslett. 43: 15-16.
Any site-directed mutagenesis procedure may be used in the present invention. There are many commercial kits available that can be used to prepare variants. The skilled person in the art is well-aware of such commercial kits and how to use them.
Synthetic gene construction entails in vitro synthesis of a designed polynucleotide molecule to encode a polypeptide of interest. Gene synthesis may be performed utilizing a number of techniques, such as the multiplex microchip-based technology described by Tian et al. (2004, Nature 432: 1050-1054) and similar technologies wherein oligonucleotides are synthesized and assembled upon photo-programmable microfluidic chips.
Single or multiple amino acid substitutions, deletions, and/or insertions may be made and tested using known methods of mutagenesis, recombination, and/or shuffling, followed by a relevant screening procedure, such as those disclosed by Reidhaar-Olson and Sauer, 1988, Science 241: 53-57; Bowie and Sauer, 1989, Proc. Natl. Acad. Sci. USA 86: 2152-2156; WO 95/17413; or WO 95/22625. Other methods that may be used include error-prone PCR, phage display (e.g., Lowman et al., 1991, Biochemistry 30: 10832-10837; U.S. Pat. No. 5,223,409; WO 92/06204) and region-directed mutagenesis (Derbyshire et al., 1986, Gene 46: 145; Ner et al., 1988, DNA 7: 127).
Mutagenesis/shuffling methods may be combined with high-throughput, automated screening methods to detect activity of cloned, mutagenized polypeptides expressed by host cells (Ness et al., 1999, Nature Biotechnology 17: 893-896). Mutagenized DNA molecules that encode active polypeptides may be recovered from the host cells and rapidly sequenced using standard methods in the art. These methods allow the rapid determination of the importance of individual amino acid residues in a polypeptide.
Semi-synthetic gene construction is accomplished by combining aspects of synthetic gene construction, and/or site-directed mutagenesis, and/or random mutagenesis, and/or shuffling. Semi-synthetic construction is typified by a process utilizing polynucleotide fragments that are synthesized, in combination with PCR techniques. Defined regions of genes may thus be synthesized de novo, while other regions may be amplified using site-specific mutagenic primers, while yet other regions may be subjected to error-prone PCR or non-error prone PCR amplification. Polynucleotide subsequences may then be shuffled.
The present invention also relates to compositions comprising a variant according to the invention. Thus, the invention relates to a composition comprising a variant which is a mature form of an alpha-amylase having amylase activity and wherein said variant has an improved stability and performance.
In one embodiment, the composition comprises a variant comprising
a) a deletion and/or a substitution at two or more positions corresponding to positions R181, G182, D183, and G184 of the amino acid sequence as set forth in SEQ ID NO:1, and
b) a modification at one or more (e.g., several) positions. Preferably, the compositions are enriched in such a variant. The term “enriched” as used herein, refers to that the alpha-amylase activity of the composition has been increased, e.g., with an enrichment factor of at least 1.1.
The compositions may comprise a variant of the present invention as the major enzymatic component, e.g., a mono-component composition. In another embodiment, the composition further comprises at least one further active component.
The term “active component” as used herein, refers to any biological or non-biological molecule which in itself is active. For example, an active component is an enzyme.
Thus, in one embodiment, the further active component is an enzyme, such as a protease, lipase, cellulose, pectate lyase and mannanase. Thus, the compositions may comprise multiple enzymatic activities, such as one or more (e.g., several) enzymes selected from the group consisting of hydrolase, isomerase, ligase, lyase, oxidoreductase, or transferase, e.g., an alpha-galactosidase, alpha-glucosidase, aminopeptidase, amylase, beta-galactosidase, beta-glucosidase, beta-xylosidase, carbohydrase, carboxypeptidase, catalase, cellobiohydrolase, cellulase, chitinase, cutinase, cyclodextrin glycosyltransferase, deoxyribonuclease, endoglucanase, esterase, glucoamylase, invertase, laccase, lipase, mannosidase, mutanase, oxidase, pectinolytic enzyme, peroxidase, phytase, polyphenoloxidase, proteolytic enzyme, ribonuclease, transglutaminase, or xylanase.
In one embodiment, the composition is a detergent composition, such as a liquid or powder detergent composition.
In one embodiment, the composition is a liquid laundry or liquid dish wash composition, such as an Automatic Dish Wash (ADW) liquid detergent composition, or a powder laundry, such as a soap bar, or powder dish wash composition, such as an ADW unit dose detergent composition.
The choice of additional components is within the skills of the skilled person in the art and includes conventional ingredients, including the exemplary non-limiting components set forth below. The choice of components may include, for fabric care, the consideration of the type of fabric to be cleaned, the type and/or degree of soiling, the temperature at which cleaning is to take place, and the formulation of the detergent product. Although components mentioned below are categorized by general header according to a particular functionality, this is not to be construed as a limitation, as a component may comprise additional functionalities as will be appreciated by the skilled artisan.
In one embodiment of the present invention, the variant of the present invention may be added to a detergent composition in an amount corresponding to 0.001-100 mg of protein, such as 0.01-100 mg of protein, preferably 0.005-50 mg of protein, more preferably 0.01-25 mg of protein, even more preferably 0.05-10 mg of protein, most preferably 0.05-5 mg of protein, and even most preferably 0.01-1 mg of protein per liter of wash liquor. The term “protein” in this context is contemplated to be understood to include a variant according to the present invention.
A composition for use in automatic dish wash (ADW), for example, may include 0.0001%-50%, such as 0.001%-20%, such as 0.01%-10%, such as 0.05-5% of enzyme protein by weight of the composition.
A composition for use in laundry granulation, for example, may include 0.0001%-50%, such as 0.001%-20%, such as 0.01%-10%, such as 0.05%-5% of enzyme protein by weight of the composition.
A composition for use in laundry liquid, for example, may include 0.0001%-10%, such as 0.001-7%, such as 0.1%-5% of enzyme protein by weight of the composition.
The variants of the invention as well as the further active components, such as additional enzymes, may be stabilized using conventional stabilizing agents, e.g., a polyol such as propylene glycol or glycerol, a sugar or sugar alcohol, lactic acid, boric acid, or a boric acid derivative, e.g., an aromatic borate ester, or a phenyl boronic acid derivative such as 4-formylphenyl boronic acid, and the composition may be formulated as described in, for example, WO92/19709 and WO92/19708.
In certain markets different wash conditions and, as such, different types of detergents are used. This is disclosed in e.g. EP 1 025 240. For example, In Asia (Japan) a low detergent concentration system is used, while the United States uses a medium detergent concentration system, and Europe uses a high detergent concentration system.
A low detergent concentration system includes detergents where less than about 800 ppm of detergent components are present in the wash water. Japanese detergents are typically considered low detergent concentration system as they have approximately 667 ppm of detergent components present in the wash water.
A medium detergent concentration includes detergents where between about 800 ppm and about 2000 ppm of detergent components are present in the wash water. North American detergents are generally considered to be medium detergent concentration systems as they have approximately 975 ppm of detergent components present in the wash water.
A high detergent concentration system includes detergents where greater than about 2000 ppm of detergent components are present in the wash water. European detergents are generally considered to be high detergent concentration systems as they have approximately 4500-5000 ppm of detergent components in the wash water.
Latin American detergents are generally high suds phosphate builder detergents and the range of detergents used in Latin America can fall in both the medium and high detergent concentrations as they range from 1500 ppm to 6000 ppm of detergent components in the wash water. Such detergent compositions are all embodiments of the invention.
A variant of the present invention may also be incorporated in the detergent formulations disclosed in WO97/07202, which is hereby incorporated by reference.
Examples are given herein of preferred uses of the compositions of the present invention. The dosage of the composition and other conditions under which the composition is used may be determined on the basis of methods known in the art.
In particular, a composition according to the present invention further comprises a chelator.
The term “chelator” as used herein, refers to chemicals which form molecules with certain metal ions, inactivating the ions so that they cannot react with other elements. Thus, a chelator may be defined as a binding agent that suppresses chemical activity by forming chelates. Chelation is the formation or presence of two or more separate bindings between a ligand and a single central atom. The ligand may be any organic compound, a silicate or a phosphate. In the present context the term “chelating agents” comprises chelants, chelating agent, chelating agents, complexing agents, or sequestering agents that forms water-soluble complexes with metal ions such as calcium and magnesium. The chelate effect describes the enhanced affinity of chelating ligands for a metal ion compared to the affinity of a collection of similar non-chelating ligands for the same metal. Chelating agents having binding capacity with metal ions, in particular calcium (Ca2+) ions, and has been used widely in detergents and compositions in general for wash, such as laundry or dish wash. Chelating agents have however shown themselves to inhibit enzymatic activity. The term chelating agent is used in the present application interchangeably with “complexing agent” or “chelating agent” or “chelant”.
Since most alpha-amylases are calcium sensitive the presence of chelating agents these may impair the enzyme activity. The calcium sensitivity of alpha-amylases can be determined by incubating a given alpha-amylase in the presence of a strong chelating agent and analyze the impact of this incubation on the activity of the alpha-amylase in question. A calcium sensitive alpha-amylase will lose a major part or all of its activity during the incubation. Chelating agent may be present in the composition in an amount from 0.0001 wt % to 20 wt %, preferably from 0.01 to 10 wt %, more preferably from 0.1 to 5 wt %.
Non-limiting examples of chelating agents are; EDTA, DTMPA, HEDP, and citrate. Thus, in one embodiment, the composition comprises a variant according to the invention and a chelating agent, such as EDTA, DTMPA, HEDP or citrate.
The term “EDTA” as used herein, refers to ethylene-diamine-tetra-acetic acid which falls under the definition of “strong chelating agents”.
The term “DTMPA” as used herein, refers to diethylenetriamine penta(methylene phosphonic acid). DTMPA can inhibit the scale formation of carbonate, sulfate and phosphate.
The term “HEDP” as used herein, refers to hydroxy-ethane diphosphonic acid, which falls under the definition of “strong chelating agents”.
The chelate effect or the chelating effect describes the enhanced affinity of chelating ligands for a metal ion compared to the affinity of a collection of similar nonchelating ligands for the same metal. However, the strength of this chelate effect can be determined by various types of assays or measure methods thereby differentiating or ranking the chelating agents according to their chelating effect (or strength).
In an assay the chelating agents may be characterized by their ability to reduce the concentration of free calcium ions (Ca2+) from 2.0 mM to 0.10 mM or less at pH 8.0, e.g. by using a test based on the method described by M. K. Nagarajan et al., JAOCS, Vol. 61, no. 9 (September 1984), pp. 1475-1478.
For reference, a chelator having the same ability to reduce the concentration of free calcium ions (Ca2+) from 2.0 mM to 0.10 mM at pH as EDTA at equal concentrations of the chelator are said to be strong chelators.
The composition of the present invention may be in any convenient form, e.g., a bar, a homogenous tablet, a tablet having two or more layers, a pouch having one or more compartments, a regular or compact powder, a granule, a paste, a gel, or a regular, compact or concentrated liquid. There are a number of detergent formulation forms such as layers (same or different phases), pouches, as well as forms for machine dosing unit.
Pouches can be configured as single or multicompartments. It can be of any form, shape and material which is suitable for hold the composition, e.g. without allowing the release of the composition from the pouch prior to water contact. The pouch is made from water soluble film which encloses an inner volume. Said inner volume can be divided into compartments of the pouch. Preferred films are polymeric materials preferably polymers which are formed into a film or sheet. Preferred polymers, copolymers or derivatives thereof are selected polyacrylates, and water soluble acrylate copolymers, methyl cellulose, carboxy methyl cellulose, sodium dextrin, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, malto dextrin, poly methacrylates, most preferably polyvinyl alcohol copolymers and, hydroxypropyl methyl cellulose (HPMC). Preferably the level of polymer in the film for example PVA is at least about 60%. Preferred average molecular weight will typically be about 20,000 to about 150,000. Films can also be of blend compositions comprising hydrolytically degradable and water soluble polymer blends such as polyactide and polyvinyl alcohol (known under the Trade reference M8630 as sold by Chris Craft In. Prod. Of Gary, Ind., US) plus plasticisers like glycerol, ethylene glycerol, Propylene glycol, sorbitol and mixtures thereof. The pouches can comprise a solid laundry cleaning composition or part components and/or a liquid cleaning composition or part components separated by the water soluble film. The compartment for liquid components can be different in composition than compartments containing solids. Ref: (US2009/0011970 A1).
Detergent ingredients may be separated physically from each other by compartments in water dissolvable pouches or in different layers of tablets. Thereby negative storage interaction between components may be avoided. Different dissolution profiles of each of the compartments can also give rise to delayed dissolution of selected components in the wash solution.
A liquid or gel detergent, which is not unit dosed, may be aqueous, typically containing at least 20% by weight and up to 95% water, such as up to about 70% water, up to about 65% water, up to about 55% water, up to about 45% water, up to about 35% water. Other types of liquids, including without limitation, alkanols, amines, diols, ethers and polyols may be included in an aqueous liquid or gel. An aqueous liquid or gel detergent may contain from 0-30% organic solvent. A liquid or gel detergent may be non-aqueous.
Another form of composition is in the form of a soap bar, such as a laundry soap bar, and may be used for hand washing laundry, fabrics and/or textiles. The term “soap bar” as used herein, refers to includes laundry bars, soap bars, combo bars, syndet bars and detergent bars. The types of bar usually differ in the type of surfactant they contain, and the term laundry soap bar includes those containing soaps from fatty acids and/or synthetic soaps. The laundry soap bar has a physical form which is solid and not a liquid, gel or a powder at room temperature. The term “solid” as used herein, refers to a physical form which does not significantly change over time, i.e. if a solid object (e.g. laundry soap bar) is placed inside a container, the solid object does not change to fill the container it is placed in. The bar is a solid typically in bar form but can be in other solid shapes such as round or oval.
The soap bar may also comprise complexing agents like EDTA and HEDP, perfumes and/or different type of fillers, surfactants e.g. anionic synthetic surfactants, builders, polymeric soil release agents, detergent chelators, stabilizing agents, fillers, dyes, colorants, dye transfer inhibitors, alkoxylated polycarbonates, suds suppressers, structurants, binders, leaching agents, bleaching activators, clay soil removal agents, anti-redeposition agents, polymeric dispersing agents, brighteners, fabric softeners, perfumes and/or other compounds known in the art.
The soap bar may be processed in conventional laundry soap bar making equipment such as but not limited to: mixers, plodders, e.g. a two stage vacuum plodder, extruders, cutters, logo-stampers, cooling tunnels and wrappers. The invention is not limited to preparing the soap bars by any single method. The premix of the invention may be added to the soap at different stages of the process. For example, the premix comprising a soap, an enzyme, optionally one or more additional enzymes, a protease inhibitor, and a salt of a monovalent cation and an organic anion may be prepared and the mixture may then plodded. The enzyme and optional additional enzymes may be added at the same time as an enzyme inhibitor, e.g. a protease inhibitor, for example in liquid form. Besides the mixing step and the plodding step, the process may further comprise the steps of milling, extruding, cutting, stamping, cooling and/or wrapping.
The present invention further relates to the use of a variant according to the present invention in a cleaning process such as laundry or hard surface cleaning including automated dish wash and industrial cleaning. The soils and stains that are important for cleaning are composed of many different substances, and a range of different enzymes, all with different substrate specificities, have been developed for use in detergents both in relation to laundry and hard surface cleaning, such as dishwashing. These enzymes are considered to provide an enzyme detergency benefit, since they specifically improve stain removal in the cleaning process that they are used in, compared to the same process without enzymes. Stain removing enzymes that are known in the art include enzymes such as proteases, amylases, lipases, cutinases, cellulases, endoglucanases, xyloglucanases, pectinases, pectin lyases, xanthanases, peroxidases, haloperoxygenases, catalases and mannanases.
In one embodiment, the invention relates the use of variants of the present invention in detergent compositions, for use in cleaning hard-surfaces, such as dish wash, or in laundering or for stain removal. In another embodiment, the invention relates to the use of an alpha-amylase variant according to the invention in a cleaning process such as laundry or hard surface cleaning including, but not limited to, dish wash and industrial cleaning. Thus, in one embodiment, the invention relates to the use of a variant which is a mature form of an alpha-amylase having amylase activity and wherein said variant has an improved stability and performance in a cleaning process such as laundry or hard surface cleaning including dish wash and industrial cleaning.
In a particular embodiment, the invention relates to the use of a variant comprising a) a substitution and/or deletion of two, three or four positions in the parent alpha-amylase said positions corresponding to positions 181, G182, D183, and G184 of the mature polypeptide of SEQ ID NO: 1; and
b) a modification at one or more (e.g., several) positions, in a cleaning process such as laundry or hard surface cleaning including dish wash and industrial cleaning.
In one embodiment of the invention relates the use of a composition according to the invention comprising a variant of the present invention together with one or more surfactants and optionally one or more detergent components, selected from the list comprising of hydrotropes, builders and co-builders, bleaching systems, polymers, fabric hueing agents and adjunct materials, or any mixture thereof in detergent compositions and in detergent applications.
A further embodiment is the use of the composition according to the invention comprising a variant of the present invention together with one or more surfactants, and one or more additional enzymes selected from the group comprising of proteases, lipases, cutinases, cellulases, endoglucanases, xyloglucanases, pectinases, pectin lyases, xanthanases, peroxidases, haloperoxygenases, catalases and mannanases, or any mixture thereof in detergent compositions and in detergent applications.
In another aspect, the invention relates to a laundering process which may be for household laundering as well as industrial laundering. Furthermore, the invention relates to a process for the laundering of textiles (e.g. fabrics, garments, cloths etc.) where the process comprises treating the textile with a washing solution containing a detergent composition and an alpha-amylase of the present invention. The laundering can for example be carried out using a household or an industrial washing machine or be carried out by hand using a detergent composition containing a glucoamylase of the invention.
In another aspect, the invention relates to a dish wash process which may be for household dish wash as well as industrial dish wash. The term “dish wash” as used herein, refers to both manual dish wash and automated dish wash. Furthermore, the invention relates to a process for the washing of hard surfaces (e.g. cutlery such as knives, forks, spoons; crockery such as plates, glasses, bowls; and pans) where the process comprises treating the hard surface with a washing solution containing a detergent composition and an alpha-amylase variant of the present invention. The hard surface washing can for example be carried out using a household or an industrial dishwasher or be carried out by hand using a detergent composition containing an alpha-amylase of the invention, optionally together with one or more further enzymes selected from the group comprising of proteases, amylases, lipases, cutinases, cellulases, endoglucanases, xyloglucanases, pectinases, pectin lyases, xanthanases, peroxidases, haloperoxygenases, catalases, mannanases, or any mixture thereof.
In a further aspect, the invention relates to a method for removing a stain from a surface comprising contacting the surface with a composition comprising an alpha-amylase of the present invention together with one or more surfactants and optionally one or more detergent components selected from the list comprising of hydrotropes, builders and co-builders, bleaching systems, polymers, fabric hueing agents and adjunct materials, or any mixture thereof in detergent compositions and in detergent applications. A further aspect is a method for removing a stain from a surface comprising contacting the surface with a composition comprising an alpha-amylase variant of the present invention together with one or more surfactants, one or more additional enzymes selected from the group comprising of proteases, lipases, cutinases, cellulases, endoglucanases, xyloglucanases, pectinases, pectin lyases, xanthanases, peroxidases, haloperoxygenases, catalases and mannanases, or any mixture thereof in detergent compositions and in detergent applications.
The present invention provides alpha-amylase variants that have an improved wash performance as compared to the parent alpha-amylase. Evaluation of the wash performance has been determined by use of Automatic Mechanical Stress Assay (AMSA). With the AMSA test the wash performance of a large quantity of small volume enzyme-detergent solutions can be examined. The AMSA plate has a number of slots for test solutions and a lid firmly squeezing the textile swatch to be washed against all the slot openings. During the washing time, the plate, test solutions, textile and lid were vigorously shaken to bring the test solution in contact with the textile and apply mechanical stress in a regular, periodic oscillating manner. For further description see WO 02/42740, especially the paragraph “Special method embodiments” at page 23-24.
A test solution comprising water (6° dH), 0.79 g/L detergent, e.g. Model detergent J as described below, and the enzyme of the invention at concentration of 0, 0.05 or 0.2 mg enzyme protein/L, is prepared. Fabrics stained with starch (CS-28 from Center For Test materials BV, P.O. Box 120, 3133 KT, Vlaardingen, The Netherlands) was added and washed for 20 minutes at 15° C. and 30° C., or alternatively 20 minutes at 15° C. and 40° C. as specified below. After thorough rinse under running tap water and drying in the dark, the light intensity values of the stained fabrics were subsequently measured as a measure for wash performance. The test with 0 mg enzyme protein/L was used as a blank and corresponded to the contribution from the detergent. Preferably mechanical action is applied during the wash step, e.g. in the form of shaking, rotating or stirring the wash solution with the fabrics. The AMSA wash performance experiments were conducted under the experimental conditions specified below:
Water hardness was adjusted to 6° dH by addition of CaCl2, MgCl2, and NaHCO3 (Ca2+:Mg2+:HCO3
Water hardness was adjusted to 15° dH by addition of CaCl2, MgCl2, and NaHCO3 (Ca2+:Mg2+:HCO3
The wash performance was measured as the brightness expressed as the intensity of the light reflected from the sample when illuminated with white light. When the sample was stained the intensity of the reflected light was lower, than that of a clean sample. Therefore the intensity of the reflected light can be used to measure wash performance.
Color measurements were made with a professional flatbed scanner (EPSON Expression 10000XL, EPSON) used to capture an image of the washed textile.
To extract a value for the light intensity from the scanned images, 48→24 Bit Color pixel values from the image were converted into values for red, green and blue (RGB). The intensity value (Int) is calculated by adding the RGB values together as vectors and then taking the length of the resulting vector:
Int=√{square root over (r2+g2+b2)}
The term “improved wash performance” of the present experiment is defined as displaying an alteration of the wash performance of a variant of the present invention relative to the wash performance of the polypeptide having an amino acid sequence as set forth in SEQ ID NO: 15. The alteration may e.g. be seen as increased stain removal. Improved wash performance was determined as described above. The wash performance was considered to be improved if the Improvement Factor (IF) is at least 1.0, preferably at least 1.05 in one or more of the conditions listed above; i.e. either in Model detergent A at 15° C. or 40° C., where the variant concentration was 0.05 or 0.2 mg/L or in Model detergent J at 15° C. or 30° C., where the variant concentration was 0.05 or 0.2 mg/L The wash conditions were as described above in Tables A and C.
The terms “Delta intensity” or “Delta intensity value” as used herein refers to the result of an intensity measurement of a test material, e.g. a swatch CS-28 (Center For Testmaterials BV, P.O. Box 120, 3133 KT Vlaardingen, the Netherlands)—. The swatch was measured with a portion of the swatch, washed under identical conditions, as background. The delta intensity is the intensity value of the test material washed with amylase subtracting the intensity value of the test material washed without amylase.
The invention described and claimed herein is not to be limited in scope by the specific aspects herein disclosed, since these aspects are intended as illustrations of several aspects of the invention. Any equivalent aspects are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. In the case of conflict, the present disclosure including definitions will control.
In order to determine whether the variants generated as described have maintained or even improved stability, the variants can be evaluated by the Phadebas assay. The following detergent compositions are prepared;
4:1 molar ratio of CaCl2 and MgCl2 stock solution with 6 dH (water hardness)
125.8 g of CaCl2.2H2O is weighed into 1 liter bottle and to this 500 ml of water is added and stirred well. To this 43.8 g of MgCl2.6H2O is weighed and added and dissolved well and the final volume is made up to 1000 ml with water.
1 tablet is suspended in 10 ml of the detergent solutions.
Buffer: 100 mM MOPS buffer pH 8. Used for dilution of supernatants to reach an usefull activity window.
Colonies are picked from the transformed plate by colony picker (KBiosystems) and innoculated in 96-well culture plate comprising TB-Gly media for growth. The cultures are grown for 3 days at 37° C. and the supernatant is recovered from the plates by centrifugation.
20 ul of culture supernatant is transferred into two 96 well plates named as Unstress and Stress. To this 80 ul of detergent eventually with EDTA, HEDP or other stressing chemical included, is added, and mixed well. The Unstressed plate is incubated at 4° C. for 16 hrs and Stressed plates are incubated at 43° C. for 16 hrs. The Unstress and Stress samples are diluted 20× in buffer. 20 ul of the diluted culture is added to the pre-dispensed substrate plate and mixed well. The plate is incubated for 20 min at 25° C. with shaking (900 rpm). After the incubation the plate is allowed to settle for 5 mins. 50 ul of the supernatant is transferred into 384 well plates and the absorbance is measured at 620 nm.
The stability is calculated as % Residual activity of the ratio between Stress and Unstress sample (% RA=stress/unstress*100). The Improvement Factor (IF) is calculated as: % RA of variant/% RA of WT.
| Number | Date | Country | Kind |
|---|---|---|---|
| 15166869.6 | May 2015 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2016/060357 | 5/9/2016 | WO | 00 |
