Claims
- 1. A method for converting a non-reducing saccharide, comprising the step of:
- introducing a recombinant DNA carrying a self-replicable vector and a nucleotide sequence coding for the expression of a variant of an enzyme of SEQ ID NO: 2 or SEQ ID NO: 4, which variant acts on a non-reducing saccharide having a trehalose structure as an end unit and having a degree of glucose polymerization of 3 or higher to release trehalose, into a host microorganism to obtain a recombinant microorganism, wherein the variant has an amino acid sequence of SEQ ID NO: 2 or SEQ ID NO: 4 with one or more amino acid residues in SEQ ID NO: 2 or SEQ ID NO: 4 deleted, replaced with different amino acids, or supplemented with one or more amino acids without substantially altering the activity of the enzyme of SEQ ID NO: 2 or SEQ ID NO: 4;
- culturing said recombinant microorganism having said recombinant DNA for expression of said variant enzyme in a nutrient culture medium to accumulate said variant enzyme;
- recovering said accumulated variant enzyme; and
- subjecting said non-reducing saccharine to the action of said recovered variant enzyme possessing trehalose releasing activity to convert said non-reducing saccharide.
- 2. The method according to claim 1, wherein said non-reducing saccharide is prepared by successively treating an amylaceous substance selected from the group consisting of starch, amylopectin, amylose, and mixtures thereof, with acid in combination with or without amylase.
- 3. The method according to claim 1, wherein said non-reducing saccharide is selected from the group consisting of .alpha.-glucosyltrehalose, .alpha.-maltosyltrehalose, .alpha.-maltotriosyltrehalose, .alpha.-maltotetraosyltrehalose, .alpha.-maltopentaosyltrehalose, and mixtures thereof.
- 4. The method according to claim 1, wherein said non-reducing saccharide has a concentration of 50 w/v % or lower in solution, and said subjecting step is carried out at a temperature of about 40.degree.-55.degree. C. and a pH in a range of about 6-8.
- 5. The method according to claim 1, wherein the variant has one or more amino acid residues in SEQ ID NO: 2 or SEQ ID NO: 4 replaced with different amino acids without substantially altering the activity of the enzyme of SEQ ID NO: 2 or SEQ ID NO: 4.
- 6. The method according to claim 1, wherein the variant has one or more amino acid residues in SEQ ID NO: 2 or SEQ ID NO: 4 deleted without substantially altering the activity of the enzyme of SEQ ID NO: 2 or SEQ ID NO: 4.
- 7. The method according to claim 1, wherein the variant has one or more amino acid residues in SEQ ID NO: 2 or SEQ ID NO: 4 supplemented with one or more amino acids without substantially altering the activity of the enzyme of SEQ ID NO: 2 or SEQ ID NO: 4.
Priority Claims (2)
Number |
Date |
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Kind |
6-59834 |
Mar 1994 |
JPX |
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6-59840 |
Mar 1994 |
JPX |
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Parent Case Info
This is a continuation of parent application Ser. No. 08/607,321 filed Feb. 26, 1996, now issued as U.S. Pat. No. 5,716,813, which is a divisional of application Ser. No. 08/399,646, filed Mar. 7, 1995, now issued as U.S. Pat. No. 5,556,781.
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Divisions (1)
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Number |
Date |
Country |
Parent |
399646 |
Mar 1995 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
607321 |
Feb 1996 |
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