Production of cellulase enzymes and hydrolysis of steam-exploded wood
Steam-exploded aspen has been examined as a candidate feedstock for both cellulase production and enzymatic hydrolysis of wood. Batch and fed-batch cultivation methods were evaluated and compared with previous experiments using ball-milled, crystalline cellulose (Solka Floc). Batch cultivation of Trichoderma reesei Rut C-30 on 9 wt% water-washed aspen yielded enzyme productivities and activities comparable to those obtained on Solka Floc (40 FP IU/l-h; 7.5 FP IU/ml). Fed-batch cultivation of Rut C-30 resulted in higher enzyme productivities and titers than batch cultivation (50 FP IU/l-h; 15 FP IU/ml). However, the overall enzyme production performance was lower than Solka Floc at comparable cellulose feeding rates and concentrations. This may be due to the accumulation of steam explosion by-products and lignin in the fermentor. The hydrolysis of water-washed steam-exploded aspen was performed at different enzyme loading and wood concentrations. Glucose production, using 10 and 15 wt% suspension, showed that while glucose concentration increased with wood load, the yield of glucose derived from cellulose decreased. With 10 wt% suspensions, it was possible to obtain a cellulose conversion to glucose above 95%. Low cellobiose levels in the hydrolyzates indicated that the enzyme preparations have ..beta..-glucosidase to filter paper activity ratios (approximately 1.5), a significant result since the fungus was grown exclusively on wood. It also suggested that the observed yield decrease is more likly to be caused by glucose than cellobiose inhibition of the enzymes. 9 references.
- Research Organization:
- Univ. of California, Berkeley
- OSTI ID:
- 5367423
- Journal Information:
- Biotechnol. Bioeng.; (United States), Vol. 28:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
CELLULASE
BIOSYNTHESIS
TRICHODERMA VIRIDE
BATCH CULTURE
SEMIBATCH CULTURE
WOOD
ENZYMATIC HYDROLYSIS
ASPENS
BIOREACTORS
CELLULOSE
ENZYME ACTIVITY
GLUCOSE
HEAT TREATMENTS
LOADING RATE
PRODUCTION
STEAM
ALDEHYDES
CARBOHYDRATES
CHEMICAL REACTIONS
DECOMPOSITION
ENZYMES
FUNGI
GLYCOSYL HYDROLASES
HEXOSES
HYDROLASES
HYDROLYSIS
LYSIS
MONOSACCHARIDES
O-GLYCOSYL HYDROLASES
ORGANIC COMPOUNDS
PLANTS
POLYSACCHARIDES
SACCHARIDES
SOLVOLYSIS
SYNTHESIS
TREES
TRICHODERMA
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