11-72: Production of organic acids from xylose rich hydrolysate by bacterial fermentation

As technological improvements continue to reduce the cost of bio-based chemicals and the sugars from food sources become more costly, unlocking the potential in cellulosic biomass will become essential to competitive manufacturing economics.  In this study we describe our ability to maximize sugar yields from hemicelluloses for fermentation to produce organic acids.  Dilute acid pretreatment conditions were optimized for sugarcane bagasse and other cellulosic feedstocks using the customized laboratory scale steam reactors for maximized C5 monomeric sugars release with minimal degradation products generation.  The xylose rich hydrolysate produced at optimized pretreatment conditions was tested by bacterial fermentation to produce either succinic acid or lactic acid using Myriant Technologies’ proprietary Escherichia coli organisms.  Strain TG400 was evolved on a xylose medium for production of succinic acid and subsequently utilized for fermentation of hemicelluloses hydrolysate.  Lessons learned from TG400 were then applied to TG160, a D-lactic acid production strain.  Further improvements are currently underway using metabolic evolution to select for strains capable of more efficient fermentation of hemicellulose hydrolysate.