Bioconversion of cellulose into ethanol by Clostridium thermocellum--product inhibition
Direct anaerobic bioconversion of cellulosic substances into ethanol by Clostridium thermocellum ATCC 27405 has been carried out at 60/sup 0/C and pH 7.0 (initial for 100 L under continuous sparging of oxygen free nitrogen in a culture vessel. Raw bagasse, mild alkali-treated bagasse, and solka floc were used as substrates. The extent of conversion of raw bagasse (cellulose, 50%; hemicellulose, 25%; lignin, 19%) was observed as 52% (w/w) and 79% (w/w) in the case of mild alkali and steam-treated bagasse (cellulose, 72%; hemicellulose, 11%; lignin, 12%), respectively. Use of bagasse concentration above 10 g/L showed a decreased rate in ethanol production. An inoculum age between 28-30 h and cell mass content of 0.027-0.036 g/L (dry basis) were used. The results obtained with raw and pretreated bagasse have been compared with those of highly pure Solka Floc (hemicellulose, 10%). Studies on the product inhibition indicated a linear fall of the percent of survivors with time. An Arrhenius type correlation between the cell decay rate constant and the product concentration was predicted. Even at low levels, the inhibitory effects of products on cell viability, the specific growth rate, and extracellular enzyme were observed.
- Research Organization:
- Biochemical Engineering Research Centre, Indian Institute of Technology, Hauz Khas, New Delhi, 110 016
- OSTI ID:
- 5647353
- Journal Information:
- Biotechnol. Bioeng.; (United States), Vol. XXV:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CELLULOSE
FERMENTATION
ETHANOL
PRODUCTION
ALKALINE HYDROLYSIS
ANAEROBIC CONDITIONS
BAGASSE
CLOSTRIDIUM THERMOCELLUM
HEAT TREATMENTS
STEAM
AGRICULTURAL WASTES
ALCOHOLS
BACTERIA
BIOCONVERSION
CARBOHYDRATES
CHEMICAL REACTIONS
CLOSTRIDIUM
DECOMPOSITION
HYDROLYSIS
HYDROXY COMPOUNDS
LYSIS
MICROORGANISMS
ORGANIC COMPOUNDS
ORGANIC WASTES
POLYSACCHARIDES
SACCHARIDES
SOLVOLYSIS
WASTES
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