Submitted to: Biotechnology for Fuels and Chemicals Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2002
Publication Date: N/A
Technical Abstract: The production of aldehydes, that are microbial inhibitors, may occur when hexoses and pentoses are exposed to temperatures above 150 deg C and acidic pH in water. These are common conditions encountered when biomass is pretreated. Concentrations of about 0.1% or higher of the degradation product, furfural, strongly inhibit fermentation as was confirmed for hydrolysate that contained 0.5% (w/o) furfural. This paper reports contacting of a polymeric adsorbent, XAD-4, with biomass hydrolysate that contains furfural. Liquid chromatographic analysis of the remaining effluent showed that furfural concentrations were less than 0.01 g/L in contrast to the initial concentrations, which were in the range of 1 to 5 g/L. Fermentation of the resulting sugars with recombinant E. coli ethanologenic strain K011 confirmed that the concentration of furfural in the hydrolysate was at a low enough level that the inhibition effect was negligible. Fermentation of XAD-4 treated hydrolysate with E. coli K011 was near as rapid as the control medium, which was formulated with reagent grade sugars of the same concentration. Ethanol yields for both fermentations were 90% of theoretical. Modeling of the adsorptive properties of this styrene-based adsorbent indicates that it is suitable for on-off chromatography and could be useful for removing small amounts of aldehydes that might otherwise inhibit fermentation.