|Mcgarvey, Jeffery - Jeff|
Submitted to: International Scholarly Research Network (ISRN)
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/20/2012
Publication Date: 6/14/2012
Citation: Williams, K., Zheng, Y., Mcgarvey, J.A., Fan, Z., Zhang, R. 2012. Ethanol and volatile fatty acid production from lignocellulse by Clostridium cellulolyticum. International Scholarly Research Network (ISRN). 2013:1-7. Interpretive Summary: Lignocellulose is a common waste product of plant agriculture. We examined the potential of a bacterium (Clostridium cellulolyticum) to convert this waste product to ethanol, a biofuel, using several different methodologies. We found that this bacterium was able to convert lignocelluloses to ethanol and several other volatile fatty acids.
Technical Abstract: Rice straw and grape pomace are two lignocellulosic substrates that are common in California. Clostridium cellulolyticum is capable of producing glycosyl hydrolase enzymes as well as fermentation products including ethanol and acetate. In this study, the potential of using C. cellulolyticum for ethanol and volatile fatty acid production from straw and grape pomace was examined. For rice straw, the effects of alkaline pretreatmentand substrate sterilization prior to fermentation on products yields were also investigated.Effects of alkaline pretreatment and necessity for subsequent washing were tested for two types of grape pomace. Fermentations were run in triplicate and lasted 20 days.For rice straw, the highest ethanol yield was 0.16 g/gVS from the straw pretreated with 10% sodium hydroxide loading(g NaOH/100g dry straw) at 121°C for 1 hour. Sterilization of the straw prior to fermentation substrate was found to be not significant for ethanol production from straw. Sterilization appeared to decrease native acetogen populations in the rice straw and decreased acetic acid yields. The highest ethanol yield from grape pomace was of 0.09 g/gVS from the pretreated pomace.Thepomace type (red or white) and washing were found to be not significant. Ethanol yields by C. cellulolyticum were lower than those from yeast in a simultaneous saccharification and fermentation system, but overall conversion of cellulose and hemicellulose was high, between 68-79%. C. cellulolyticum may have potential for a mixed fermentation biofuels production system.