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Poster Presentation 2-13
Effect of Corn Stover Hydrolysate and Temperature on Fermentation Performance of Various Yeast Strains
Kent Evans, Ali Mohagheghi, Jenny Hamilton, Kelly Ibsen, and Min Zhang
National Bioenergy Center Biotechnology Division for Fuels and ChemicalsNational Renewable Energy Laboratory 1617 Cole Boulevard Golden, Colorado 80401
Telephone: (303) 384-6845; Fax: (303) 384-6877; E-mail: kent_evans@nrel.gov
Technoeconomic analysis of a biomass to ethanol process shows a 7.7% cost savings of ethanol per gallon using a fermentative organism tolerant to acid-pretreated biomass hydrolysate and elevated temperatures. The cost saving is translated from the reduction of contamination and subsequent product loss and the elimination of ion exchange chromatography used in the process to detoxify the hydrolysate stream. An evaluation was conducted to examine the effect of corn stover hydrolysate (neutralized) and temperature on fermentation performance of various yeast strains. Twenty-seven strains were selected from literature and screened for fermentation performance in the presence of 0, 25%, 50%, 75% and 90% hydrolysate, and at 30oC, 35oC, 40oC and 42oC. While many strains maintained high ethanol yield in 90% v/v hydrolysate, the ethanol productivity was reduced significantly (about 50-70%) as compared to the 0% hydrolysate control, indicating toxicity effect of the hydrolysate on cell growth and fermentation. Among the six strains with higher ethanol productivity, Candida acidothermophilum ATCC20381 demonstrated the greatest tolerance to hydrolysate. Ten strains performed well up to 42°C. C. acidothermophilum ATCC20381 and Saccharomyces cerevisiae ATCC26602 demonstrated the greatest tolerance to both conditions.
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