Claims
- 1. A method for producing a thermostable xylanase selected from the thermostable xylanase XP1 or XP2 having the following physicochemical properties:
- (1) Thermostable xylanase XP1 having the following physicochemical properties:
- I) Action: hydrolyzing the 1,4-.beta.-D-xyloside bond of xylan to thereby produce reducing sugars of xylooligosaccharides
- ii) Substrate specificity: acting on prepared xylans including birch xylan and oat spelt xylan, as well as xylan-containing materials including hardwood kraft pulp and oat spelt bran
- iii) Optimum pH and stable pH ranges: optimum pH for reaction ranging from 5 to 8 and the pH at which said xylanase is stable ranging from 3 to 9
- iv) Appropriate temperature range for action: 50.degree. to 80.degree. C.
- v) Thermostability: retaining about 90% or more enzyme activity after a 30 min treatment at 50.degree. C. and exhibiting a residual activity of about 50% or more even after a 30 min treatment at 60.degree. C.
- vi) Isoelectric point: around 8.1
- vii) Molecular weight: approximately 22,500 as determined by SDS polyacrylamide gel electrophoresis
- viii) Inhibition: weakly inhibited by iodoacetic acid and EDTA and strongly inhibited by Hg.sup.2+ and SDS
- (2) Thermostable xylanase XP2 having the following physicochemical properties:
- I) Action: hydrolyzing the 1,4-p-.beta.-D-xyloside bond of xylan to thereby produce reducing sugars of xylose and xylooligosaccharides
- ii) Substrate specificity: acting on prepared xylans including birch xylan and oat spelt xylan, as well as xylan-containing materials including hardwood kraft pulp and oat spelt bran
- iii) Optimum pH and stable pH ranges: optimum pH for reaction ranging from 5 to 8 and the pH at which said xylanase is stable ranging from 4.5 to 9
- iv) Appropriate temperature range for action: 60 to 90.degree. C.
- v) Thernostability: exhibiting a residual activity of about 90% or more after a 30 min treatment at 70.degree. C.
- vi) Isoelectric point: around 8.5
- vii) Molecular weight: approximately 32,000 as determined by SDS polyacrylamide gel electrophoresis
- viii) Inhibition: weakly inhibited by Mn.sup.2+, Co.sup.2+, Cu.sup.2+, EDTA and iodoacetic acid and strongly inhibited by Hg.sup.2+ and SDS, comprising culturing on a medium a microorganism belonging to the genus Bacillus which produces said thermostable xylanase and subsequently recovering the thermostable xylanase from the resultant culture.
- 2. The method of claim 1, wherein the microorganism is Bacillus sp. 2113 (Ferm BP-5264) or Bacillus sp. 208 (Ferm BP-5321).
- 3. A biologically pure culture of Bacillus sp. 2113 (Ferm BP-5264) or Bacillus sp. 208 (Ferm BP-5321) having an ability to produce a thermostable xylanase.
- 4. A bleaching agent containing, as an active ingredient, a microorganism belonging to the genus Bacillus which produces a thermostable xylanase selected from the thermostable xylanase XP1 or XP2 having the following physicochemical properties:
- (1) Thermostable xylanase XP1 having the following physicochemical properties:
- I) Action: hydrolyzing the 1,4-.beta.-D-xyloside bond of xylan to thereby produce reducing sugars of xylooligosaccharides
- ii) Substrate specificity: acting on prepared xylans including birch xylan and oat spelt xylan, as well as xylan-containing materials including hardwood kraft pulp and oat spelt bran
- iii) Optimum pH and stable pH ranges: optimum pH for reaction ranging from 5 to 8 and the pH at which said xylanase is stable ranging from 3 to 9
- iv) Appropriate temperature range for action: 50 to 80.degree. C.
- v) Thermostability: retaining about 90% or more enzyme activity after a 30 min treatment at 50.degree. C. and exhibiting a residual activity of about 50% or more even after a 30 min treatment at 60.degree. C.
- vi) Isoelectric point: around 8.1
- vii) Molecular weight: approximately 22,500 as determined by SDS polyacrylamide gel electrophoresis
- viii) Inhibition: weakly inhibited by iodoacetic acid and EDTA and strongly inhibited by Hg.sup.2+ and SDS
- (2) Thermostable xylanase XP2 having the following physicochemical properties:
- I) Action: hydrolyzing the 1,4-.beta.-D-xyloside bond of xylan to thereby produce reducing sugars of xylose and xylooligosaccharides
- ii) Substrate specificity: acting on prepared xylans including birch xylan and oat spelt xylan, as well as xylan-containing materials including hardwood kraft pulp and oat spelt bran
- iii) Optimum pH and stable pH ranges: optimum pH for reaction ranging from 5 to 8 and the pH at which said xylanase is stable ranging from 4.5 to 9
- iv) Appropriate temperature range for action: 60.degree. to 90.degree. C.
- v) Thermostability: exhibiting a residual activity of about 90% or more after a 30 min treatment at 70.degree. C.
- vi) Isoelectric point: around 8.5
- vii) Molecular weight: approximately 32,000 as determined by SDS polyacrylamide gel electrophoresis
- viii) Inhibition: weakly inhibited by Mn.sup.2+, Co.sup.2+, Cu.sup.2+, EDTA and iodoacetic acid and strongly inhibited by Hg.sup.2+ and SDS.
- 5. A method for bleaching pulp, comprising treating pulp with the bleaching agent of claim 4.
- 6. A method for bleaching pulp, comprising carrying out a chemical bleaching and/or an alkali extraction before, after or during the treatment of pulp with the bleaching agent of claim 4.
Priority Claims (2)
Number |
Date |
Country |
Kind |
6-318450 |
Dec 1994 |
JPX |
|
7-313081 |
Nov 1995 |
JPX |
|
Parent Case Info
This is a divisional of application Ser. No. 08/575,964, filed Dec. 20, 1995, now U.S. Pat. No. 5,736,384.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
5369024 |
Jeffries et al. |
Nov 1994 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
9213942 |
Aug 1992 |
WOX |
Non-Patent Literature Citations (3)
Entry |
Okazaki et al., Agric. Biol. Chem. 49:2033-2039. |
Kang et al., Korean J. Appl. Microbiol. Bioeng. 14:447-453. |
Ball et al., Proc. 8th Intl. Symposium on Wood and Pulping Chemistry, Jun. 6-9, 1995, Helsinki, Finland, pp. 395-400. |
Divisions (1)
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Number |
Date |
Country |
Parent |
575964 |
Dec 1995 |
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