Fundamental study of the mechanism and kinetics of cellulose hydrolysis by acids and enzymes. Final report, June 1, 1978-January 31, 1981
There are three basic enzymes (e.g., endoglucanase (C/sub x/), exoglucanase (C/sub 1/) and cellobiase) comprising the majority of extracellular cellulase enzymes produced by the cellulolytic mycelial fungi, Trichoderma reesei, and other cellulolytic microorganisms. The enzymes exhibited different mode of actions in respect to the hydrolysis of cellulose and cellulose derived oligosaccharides. In combination, these enzymes complimented each other to hydrolyze cellulose to its basic constituent, glucose. The kinetics of cellobiase were developed on the basis of applying the pseudo-steady state assumption to hydrolyze cellobiose to glucose. The results indicated that cellobiase was subjected to end-product inhibition by glucose. The kinetic modeling of exoglucanase (C/sub 1/) with respect to cellodextrins was studied. Both glucose and cellobiose were found to be inhibitors of this enzyme with cellobiose being a stronger inhibitor than glucose. Similarly, endoglucanase (C/sub x/) is subject to end-product inhibition by glucose. Crystallinity of the cellulose affects the rate of hydrolysis by cellulases. Hence, the changes in crystallinity of cellulose in relation to chemical pretreatment and enzyme hydrolysis was compared. The study of cellulase biosynthesis resulted in the conclusion that exo- and endo-glucanases are co-induced while cellobiase is synthesized independent of the other two enzymes. The multiplicity of cellulase enzymes are the end results of post-translational modification during and/or after the secretion of enzymes into growth environment.
- Research Organization:
- Purdue Univ., Lafayette, IN (USA). Lab. of Renewable Resources Engineering
- DOE Contract Number:
- AS02-76ER02755
- OSTI ID:
- 6566222
- Report Number(s):
- DOE/ER/02755-5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
09 BIOMASS FUELS
CELLULASE
BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
CELLULOSE
ENZYMATIC HYDROLYSIS
CRYSTAL STRUCTURE
CARBOHYDRATES
CHEMICAL REACTIONS
DECOMPOSITION
ENZYMES
GLYCOSYL HYDROLASES
HYDROLASES
HYDROLYSIS
KINETICS
LYSIS
O-GLYCOSYL HYDROLASES
ORGANIC COMPOUNDS
POLYSACCHARIDES
REACTION KINETICS
SACCHARIDES
SOLVOLYSIS
SYNTHESIS
550200* - Biochemistry
140504 - Solar Energy Conversion- Biomass Production & Conversion- (-1989)