12-30: Rates and Yields of Cellulosic Ethanol from Maize Silage with Effect of Brown Midrib Mutations

The processing characteristics of biofuel feedstocks are strongly affected by the quantity and quality of lignin in the cell wall structure.  We present the effect of brown midrib mutations on rates and yields of cellulosic ethanol production from maize silage.  Both raw silage and silage from commercial sources were pretreated using liquid hot water (160-180°C) and assessed by enzymatic hydrolysis and fermentation using the glucose/xylose fermenting Purdue recombinant S. cerevisiae 424A (LNH-ST).  At 20% solids concentration (200 g/L), pretreated bmr silage achieved higher yields of sugars than non-bmr silage pretreated under the same conditions.  At the optimal pretreatment conditions, bmr silage achieved 62% of theoretical yield of glucose after 24 hours of enzymatic hydrolysis (15 FPU cellulase per gram glucan) compared to 50% yield from non-bmr silage.  Sugars from both silage varieties fermented to ethanol at high yields using the Purdue recombinant yeast strain.