Pretreatment of sugar cane bagasse hemicellulose hydrolyzate for ethanol production by yeast |
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Authors: | Gong C S Chen C S Chen L F |
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Institution: | (1) Genome Research Program and Laboratory of Molecular Biology, Genetic Engineering Research Institute, KIST, Taedok Science Town, PO Box 17, 305-333 Yusungku, Taejeon;(2) Department of Food Science and Technology, Kyungsung University, 608-736 Pusan, Korea |
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Abstract: | The cellulase system ofBacillus circulans F-2 effectively hydrolyzed carboxymethyl cellulose (CMC), xylan, avicel, cellobiose, filter paper, cotton, andp-nitrophenyl-Β-D-cellobioside, and the crude enzyme produced mainly glucose from digestion of avicel. Two major and one minor
peaks of enzyme activities were eluted on DEAE ion-exchange chromatography, and designated cellulase complex I(C-I) and complex
II(C-II) for the two major peaks, and cellulase-III for a minor peak. C-I and C-II were further purified on gel filtration
column of a TSK-Gel SW G3000 ×L. The molecular masses of C-I and C-II were estimated to be about 669 and 443 kDa, respectively.
Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of the C-I and C-II complexes showed that the C-I complex
was present as a multiple protein complex, consisting of at least five CMCases and two xylanases, and that the C-II complex
was consisted of at least three CMCase and four xylan ases. C-I showed high activities of cellohydrolase, CMCase, xylanase,
and Β-glucosidase, whereas C-II showed high activities of CMCase, xylanase, avicelase, and Β-glucosidase. The outstanding
property of the C-II was its high hydrolytic activity toward filter paper, a highly resistant substrate against enzymatic
degradation. However, cellulaseIII showed only strong avicelase activity. These results indicated that the cellulase system
of the strain exists as multiple complex forms. |
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Keywords: | Endo-Β -glucanase Β -glucosidase Avicelase filter paper-hydrolase enzyme complex cellulo-xylanosome Bacillus circulons F-2 |
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