skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Enzyme conversion of biomass to fermentable sugars

Technical Report ·
OSTI ID:6712923

Saccharification studies indicated the suitability of Trichoderma viride 253 crude enzyme preparation as a promising agent for saccharifying sugarcane baggase hemicellulose, treated ..cap alpha..-cellulose, and alkali-treated bagasse. Utilization of sugarcane bagasse for the fermentative production of cellulases, hemicellulases, and single cell protein (SCP) by T. viride 253 can be outlined as follows: (a) Production of extracellular cellulases and hemicellulases in a forced aeration-stirred tank fermentor using crude bagasse as the sole carbon source in Dox's culture medium. (b) Treatment of the remaining biodegraded bagasse with NaOH. (c) Refermentation in static culture of bagasse as the sole carbon source in Dox's culture medium for production of SCP material. The yeast, Pachysolen tannophilus, is capable of converting xylose and glucose to ethanol. Fermentation of the crude hydrolyzate from straw revealed low efficiencies of 40 to 60%. As anticipated, interfering substances are present in these crude substrates. Further procedures for optimization of both processing of hydrolyzates and fermentation are being investigated. Endoglucanase and cellobiase are inhibited by glucose, and cellobiose inhibits exoglucanase. A yeast (Candida wickerhamii) was isolated which ferments water soluble oligosaccharides. Because oligosaccharides (cellulodxtrins) are easier to prepare than glucose from cellulose, attention has been directed toward substrate preparation and organism characterization. While the literature contains several methods for preparing cellulodextrins, all the methods involve several steps or involve the removal or neutralization of strong acids. A simple method has been developed using trifluoroacetic acid (TFA)-water for the hydrolysis. Analysis by TLC and HPLC shows a series of cellulodextrins (DP1-6) which are completely converted to ethanol by Candida wickerhamii in 4 to 5 days.

Research Organization:
Agricultural Research Service, Peoria, IL (USA). Northern Regional Research Center
DOE Contract Number:
AI01-81AF20004
OSTI ID:
6712923
Report Number(s):
DOE/AF/20004-T1; ON: DE84010856
Country of Publication:
United States
Language:
English