Bioconversion of plant biomass to ethanol. Final report, December 1, 1979-December 31, 1980
This final report describes research performed on a process for the direct fermentation of pretreated hardwood and corn stover to ethanol. Experimental investigations were conducted on the technical problem areas that limit the utilization of lignocellulose for ethanol production, i.e., wood pretreatment, culture development, and fermentation. Considerable technical progress has been demonstrated in each area. The experimental findings have led to process design improvements that can reduce the capital cost for ethanol production. Studies on wood pretreatment to enhance carbohydrate recovery and susceptibility to enzymatic hydrolysis continued to show progress. Rapid decompression of treated fibers to atmospheric pressure was found to make little or no contribution to enhancing the rate of enzymatic hydrolysis. Acid extraction of the hemicellulose component prior to sulfur dioxide augmented wood steaming increased the overall fermentable carbohydrate recovery and, therefore, the attainable yield of ethanol. Only modest improvements in fiber digestibility are now required to meet the pretreatment goals. A new and highly cellulolytic strain of C. thermocellum, designated as strain YS, was isolated from hot springs soil samples and tested. A previously unreported effect of stirring and hydrogen on the fermentation product pattern of several strains of C. thermocellum was discovered. Mono- and co-culture fermentations were performed to understand the factors that affect the yield of ethanol. Co-culturing C. thermocellum strain YS with efficient ethanol-producing non-cellulolytic strains resulted in higher ethanol yields than that observed in strain YS mono-culture cellulose fermentation. The feasibility of ethanol production at high substrate concentrations was investigated in serum bottle experiments. The amount of ethanol produced declined as the substrate concentration increased.
- Research Organization:
- Solar Energy Research Inst. (SERI), Golden, CO (United States); General Electric Co., Schenectady, NY (USA)
- DOE Contract Number:
- AC02-77CH00178
- OSTI ID:
- 6122028
- Report Number(s):
- SERI/TR-8271-1-T1; ON: DE81031976
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AGRICULTURAL WASTES
ENZYMATIC HYDROLYSIS
FERMENTATION
CLOSTRIDIUM THERMOCELLUM
CELLULOLYTIC ACTIVITY
ETHANOL
BIOSYNTHESIS
WOOD
ACID HYDROLYSIS
CHEMICAL REACTION YIELD
DELIGNIFICATION
EXPERIMENTAL DATA
LIGNIN
MAIZE
OPTIMIZATION
PRESSURE DEPENDENCE
ALCOHOLS
BACTERIA
BIOCONVERSION
CARBOHYDRATES
CEREALS
CHEMICAL REACTIONS
CLOSTRIDIUM
DATA
DECOMPOSITION
ENZYME ACTIVITY
GRAMINEAE
GRASS
HYDROLYSIS
HYDROXY COMPOUNDS
INFORMATION
LYSIS
MICROORGANISMS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC WASTES
PLANTS
POLYSACCHARIDES
SACCHARIDES
SOLVOLYSIS
SYNTHESIS
WASTES
YIELDS
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