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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Bioenergy Research » Research » Publications at this Location » Publication #326881

Research Project: Technologies for Improving Process Efficiencies in Biomass Refineries

Location: Bioenergy Research

Title: Maleic acid treatment of bioabated corn stover liquors improves cellulose conversion to ethanol

item KIM, DAEHWAN - Purdue University
item XIMENES, EDUARDO - Purdue University
item CAO, GUANGLI - Purdue University
item Nichols, Nancy
item Frazer, Sarah
item LADISCH, MICHAEL - Harbin Institute Of Technology (HIT)

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/7/2016
Publication Date: 4/25/2016
Citation: Kim, D., Ximenes, E.A, Nichols, N.N., Cao, G., Frazer, S.E., Ladisch, M.R. 2016. Maleic acid treatment of bioabated corn stover liquors improves cellulose conversion to ethanol [abstract]. Biotechnology for Fuels and Chemicals. M66

Interpretive Summary:

Technical Abstract: Elimination of inhibitory compounds released during pretreatment of lignocellulose is critical for efficient cellulose conversion and ethanol fermentation. This study examined the effect of bioabated liquor from pretreated corn stover on enzyme hydrolysis of Solka Floc or pretreated corn stover solids. Xylo-oligosaccharides in the liquor were hydrolyzed by hemicellulase or maleic acid. Pretreatment was at 20% solids, 190', 45 min, and subsequent hydrolysis, after bioabatement was done with 5% corn stover, and ethanol fermentation by Saccharomyces cerevisiae. The fungus Coniochaeta ligniaria NRRL30616 removed inhibitory compounds in the liquor from LHW-pretreated corn stover. The conversion of cellulose to glucose in bioabated liquor was higher when the liquor was treated with maleic acid than with hemicellulase. For hemicellulase treated liquor with treated corn stover solids, cellulose conversion was 39%, and for maleic acid 68%. The observed lower glucose may be related to inhibition of beta-xylosidase that caused accumulation of xylo-oligomers, which in turn inhibited beta-glucosidase, as indicated by accumulation of cellobiose. Use of maleic acid alleviated the inhibitory effect on beta-glucosidase by hydrolyzing the xylo-oligomers to xylose. The ethanol production from Solka Floc hydrolysate or sugars from corn stover solids was 20 to 30% higher for bioabated liquor compared to non-bioabated liquor after 6 hours, with a reduction of 3 hours in the fermentation lag phase. Our results confirm bioabatement removes enzymatic and fermentation inhibitory compounds, and indicate that treatment of bioabated samples with maleic acid improves the overall cellulose conversion by removing xylo-oligomers.