Monday, April 30, 2007

Biobutanol - A superior fuel for tomorrow: Use of agricultural residues as economically novel substrates

Thaddeus Chukwuemeka Ezeji, Food Science and Human Nutrition, University of Illinois, Urbana-Champaign, 1207 West Gregory Drive, Urbana, IL 61801, Nasib Qureshi, National Center for Agricultural Utilization Research, USDA, ARS, Midwest Area, 1815 N. University Street, Peoria, IL 61604, and Hans Peter Blaschek, Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, 1207 West Gregory Drive, Urbana, IL 61801.

A detailed description of the utilization of representative mixed sugar streams (pentoses and hexoses) of lignocellulosic hydrolysates and their sugar preferences by the solventogenic clostridia will be presented. Prior work in our laboratory has demonstrated the importance of the fermentation substrate on the cost of bio-butanol. Because of the impact on butanol price, we examined the use of agricultural residues and fiber rich co-products produced during ethanol production such as corn fiber and distillers dried grains and solubles (DDGS) as potential substrates for bio-butanol production by the solventogenic clostridia. Pretreatment and hydrolysis of lignocellulosic biomass using either dilute acid, hot water, or ammonium fiber explosion (AFEX) results in a complex mixture of sugars such as hexoses (glucose, galactose, mannose), and pentoses (xylose, arabinose). However, unwanted compounds such as salts, furfural, hydroxymethyl furfural (HMF), acetic, ferulic, glucuronic, ρ-coumaric acids, and other phenolic compounds, are also produced. Details on the effect of these compounds on butanol fermentation and probable mode of inhibition on the solventogenic clostridia will also be presented.