Process for hydrolyzing starch without pH adjustment
First Claim
1. A process for liquefying starch comprising contacting a thermostable, acid-stable alpha-amylase obtained by culturing Bacillus acidocaldarius with an aqueous slurry or solution of the starch having a pH as low as 3.0, the contacting occurring at an elevated temperature and producing a liquefact having a pH of about 4.0 to 4.5 and DE of about 10-12.
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Accused Products
Abstract
An alpha-amylase enzyme obtained from Bacillus acidocaldarius species is utilized to liquefy starch at a pH as low as 3.0 without the need to add thermostabilizing agents such as calcium. The alpha-amylase produces acceptable DE yields in a single liquefaction step and does not need to be inactivated prior to conducting saccharification which can proceed without adjustment of the pH of the liquefact. Alternatively, a secondary liquefaction process can be utilized, in which case two additions of the alpha-amylase are used resulting in a combined low dosage of the enzyme.
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Citations
52 Claims
- 1. A process for liquefying starch comprising contacting a thermostable, acid-stable alpha-amylase obtained by culturing Bacillus acidocaldarius with an aqueous slurry or solution of the starch having a pH as low as 3.0, the contacting occurring at an elevated temperature and producing a liquefact having a pH of about 4.0 to 4.5 and DE of about 10-12.
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17. A process for liquefying a starch slurry comprising the following acts:
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(a) providing a thermostable, acid-stable α
-amylase prepared from a Bacillus acidocaldarius species;
(b) adding the alpha-amylase to a starch slurry having a pH between about 3.0-5.0; and
(c) heating a mixture obtained from step (b) to at least 90°
C. until a starch liquefact having a pH of about 4.0-4.5 and a DE of about 10-12 DE is obtained. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 47)
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33. A single liquefaction step process for starch comprising the following acts:
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(a) providing a starch slurry having a pH as low as about 3.0 and a thermostable, acid-stable alpha-amylase obtained from Bacillus acidocaldarius;
(b) mixing the alpha-amylase and the starch slurry; and
(c) heating the resulting mixture at at least 90°
C. until a liquefact having a pH of about 4.0 to 4.5 and a DE of about 10-12 DE is obtained. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 48)
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43. A starch liquefaction method comprising the acts of:
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(a) providing a starch slurry having a pH as low as 3.0 and an thermostable, acid-stable alpha-amylase capable of hydrolyzing starch at a pH as low as 3.0, the alpha-amylase cultured from Bacillus acidocaldarius;
(b) mixing the starch slurry and about 150 ASAA units/g of the alpha-amylase without adjusting the pH of the starch slurry; and
(c) jet cooking the mixture resulting from step (b) for about 5-8 minutes at about 105-110°
C. to obtain a liquefact having a DE of approximately 10-12. - View Dependent Claims (49)
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44. A starch liquefaction method comprising the acts of:
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(a) providing a starch slurry having a pH as low as 3.0 and an thermostable, acid-stable alpha-amylase capable of hydrolyzing starch at a pH as low as 3.0, the alpha-amylase cultured from Bacillus acidocaldarius;
(b) jet cooking the starch slurry between about 140-155°
C. for about 5-8 seconds without adjusting the pH of the starch slurry;
(c) lowering the temperature of the cooked slurry from step (b) to about 95-98°
C. and adding about 1.0 to 5.0 ASAA units/g ds of the alpha-amylase; and
(d) allowing the mixture of step c) to undergo hydrolysis for about 60-90 minutes to produce a liquefact having a DE of about 10-12. - View Dependent Claims (50)
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45. A starch liquefaction method comprising the acts of:
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(a) providing a starch slurry having a pH as low as 3.0 and an thermostable, acid-stable alpha-amylase capable of hydrolyzing starch at a pH as low as 3.0, the alpha-amylase cultured from Bacillus acidocaldarius;
(b) mixing the starch slurry with about 10-30 ASAA units/g ds of the alpha-amylase without adjusting the pH of the starch slurry;
(c) jet cooking the mixture resulting from step (b) for about 5 minutes;
(d) adding about 1-5 ASAA units/g ds of the alpha-amylase to the jet cooked mixture from step (c); and
(e) continuing liquefaction at about 95-98°
C. for as little at 30-90 minutes to obtain a liquefact having a DE of approximately 10-12. - View Dependent Claims (51)
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52. A starch liquefact prepared by the process of:
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a) mixing a starch slurry having a pH as low as 3.0 with a thermostable, acid-stable alpha-amylase derived from Bacillus caldarius;
andb) heating the mixture from act a) to at least 90°
C. until a DE of approximately 10-12 is obtained.
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Specification