Thermostable beta-amylase
AssigneeMichigan Biotechnology Institute
InventorsJoseph G. Zeikus, Hyung-Hwan Hyun
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Abstract
A thermostable and thermoactive, extracellular .beta.-amylase is produced by Clostridium thermosulfurogenes. Methods of producing the .beta.-amylase and using it to convert starch to maltose are also disclosed.
Claims3
A thermostable .beta.-amylase, substantially free of interfering saccharidase enzymatic activity from the microorganism Clostridium thermosulfurogenes, said .beta.-amylase having an optimum temperature for activity of about 75.degree. C.;
- said .beta.-amylase being stable up to 70.degree. C. in the absence of substrate and up to 80.degree. C. in the presence of substrate;
- said enzyme having optimum activity at about pH 5.5 to about 6.0 and being stable from about pH 3.5 to about 6.5.
A thermostable .beta.-amylase from Clostridium thermosulfurogenes, said .beta.-amylase having the following physiochemical properties:
- (1) Reactivity:
- It produces only maltose and limited dextrins when transforming starch hydrolysates;
- (2) Substrate specificity:
- It produces only maltose from starch or maltotetraose and glucose and maltose from maltotriose;
- (3) Optimum pH value:
- About 5.5 to about 6.0;
- (4) pH stability:
- Stable from about pH 3.5 to about 6.5;
- (5) Optimum temperature:
- 75.degree. C., 85% of maximal activity at 80.degree. C.;
- (6) Temperature stability:
- It is stable up to 70.degree. C. in the absence of substrate and up to 80.degree. C. in the presence of 5% starch;
- and
- (7) Influence of inhibitors:
- .beta.-amylase activity inhibited by metal ions (Cu.sup.++ and Hg.sup.++) and p-chloromercuribenzoate but not by calcium Schandingder dextrins or ethanol.
A method for producing a thermostable, .beta.-amylase which comprise anaerobically culturing a .beta.-amylase producing Clostridium thermosulfurogenes in a nutrient medium until substantial enzymatic activity is detectable and thereafter isolating the thermostable .beta.-amylase.
Dependencies are inferred from the claim text.