Biological pretreatment of corn stover with white-rot fungus for enzymatic hydrolysis and bioethanol production

Pretreatment, as the first step towards conversion of lignocellulosic feedstocks to biofuels and/or chemicals remains one of the main barriers to commercial success.  Typically, harsh methods are used to pretreat lignocellulosic biomass prior to its breakdown to sugars by enzymes, which also result in fermentation inhibitor formation.  An alternative to harsh chemicals is biological pretreatment to break down or remove lignin from the holocellulose surface.  We have screened 26 white-rot fungal strains using corn stover as feedstock for powerful ability to remove lignin from it with minimum loss of cellulose and hemicellulose.  We have then optimized the biological pretreatment of corn stover using the selected Phlebia brevispora for enzymatic saccharification to sugars.  The production of fuel ethanol from the pretreated corn stover by fed-batch simultaneous saccharification and fermentation (SSF) using recombinants Escherichia coli strain FBR5 and Saccharomyces cerevisiae strain YRH400 was investigated.  The results of this work will be described.  The problems of developing a large scale biological pretreatment using white-rot fungus and future directions of research will be outlined.