Poster Presentation 2-10

Use of the Ascomycete Coniochaeta ligniaria to Remove Inhibitors from Biomass-Derived Sugars

Nancy N. Nichols*¹, Bruce S. Dien¹, Gema M. Guisado² and Maria J. Lopez²

¹National Center for Agricultural Utilization Research, USDA

1815 N. University St.

Peoria, IL 61604

Phone: (309)681-6271

Fax: (309)681-6427

Email: nicholnn@ncaur.usda.gov

²University of Almeria, Almeria, Spain

Use of agricultural residues as feedstock for production of fuels and chemicals is limited in part by the presence of inhibitory substances in the sugar streams obtained from the residues. Conditions that promote the hydrolysis of glucan and xylans to free sugars also promote formation of compounds including furfural, 5-hydroxymethylfurfural (HMF), acetate, and phenolics, that may interfere with fermentations. Biological treatment of hydrolysates for inhibitor abatement is a promising strategy for abatement of microbial inhibitors in ethanol fermentations of biomass sugars. We isolated a fungus from soil that metabolizes many of the inhibitory compounds and reduces the concentration of furfural, HMF, and acetate in corn stover hydrolysates essentially to zero. The fungus, Coniochaeta ligniaria strain NRRL30616, was used to remove inhibitors from hydrolyzed corn stover, followed by saccharification and fermentation to ethanol with Saccharomyces cerevisiae. Additional strains of the same and related species were evaluated for the ability to metabolize furans, sugars, and phenolics. The isolates most closely related to NRRL30616 could metabolize furfural and HMF, and a subset of those could grow in corn stover hydrolysate. C. ligniaria is a unique species that may be useful for detoxifying biomass-derived sugar streams.