(471c) Influence of Collection Method on the Sugar and Ethanol Processing Characteristics

Due to concerns with biomass collection systems and soil sustainability there are opportunities to investigate the optimal plant fractions to collect. An ideal feedstock would require a low severity pretreatment to release a maximum amount of sugar during enzymatic hydrolysis that would be available for fermentation. Corn stover fractions were separated by hand and analyzed for glucan, xylan, acid soluble lignin, acid insoluble lignin, and ash composition. The samples were not extracted prior to compositional analysis to most closely match the conditions of a feedstock being delivered from a farm to a biorefinery. The stover fractions were also pretreated with either 0, 0.4, or 0.8% NaOH for 2 hours at room temperature, washed, autoclaved and saccharified. In addition, acid pretreated samples underwent simultaneous saccharification and fermentation (SSF) to ethanol. In general, the two pretreatments produced similar trends with cobs, husks, and leaves responding best to the pretreatments, the tops of stalks responding slightly less, and the bottom of the stalks responding the least. For example, corn husks pretreated with 0.8% NaOH released over 90% (standard error of 3.8%) of the available glucan, while only 45% (standard error of 1.1%) of the glucan was produced from identically treated stalk bottoms. Estimates of the theoretical ethanol yield using acid pretreatment followed by SSF corresponded to 63 (standard error of 11.5%) for husks and 37% (standard error of 1.2%) for stalk bottoms. This suggests that integration of biomass collection systems to remove sustainable feedstocks could be integrated with the processes within a biorefinery to minimize overall ethanol production costs.