Effects of potential inhibitors present in dilute acid-pretreated corn stover on fermentative hydrogen production by Escherichia coli

Abstract

This study reports the inhibitory compounds present in dilute sulfuric acid-pretreated corn stover for fermentative hydrogen production by Escherichia coli. The E. coli W3110-derived strain deficient in lactate and succinate production pathways was used. When dilute acid-treated corn stover liquor containing 175 mM acetate, 21 mM furfural, and 2.6 mM 5-hydroxymethylfurfural was added at fourfold dilution to the xylose-containing culture medium, the microbial growth and hydrogen production were almost completely inhibited. The addition of acetate, furfural, or 5-hydroxymethylfurfural, at up to 200, 80, or 40 mM, respectively, to the xylose- or glucose-containing medium led to dose-dependent inhibition of fermentative hydrogen production. No synergistic inhibition by furfural with acetate or 5-hydroxymethylfurfural at concentrations based on the corn stover hydrolysate was observed. Altogether, these results suggest that the inhibition of the E. coli-based hydrogen production by the corn stover hydrolysate is primarily attributed to acetate under the conditions used.