Monday, May 2, 2011
Grand Ballroom C-D, 2nd fl (Sheraton Seattle)
Experiments were performed for evaluating the effects of wet storage and drying temperature on the susceptibility of whole-cut (100% removal), field-moist corn stover feedstock to pretreatment for biochemical conversion. Corn stover with 50% moisture content was ensiled in 55-gallon barrels for one year under the following treatment conditions: 1) no additive (H2O), 2) yeast plus acid (YA), and 3) yeast, enzyme plus acid (YEA). Storage of wet corn stover by ensiling was effective for preservation of dry matter; after one year, dry matter losses were minimal (less than 2%). In all treatments, pH ranges were similar, low levels of lactic and acetic acids were measured, and ethanol production was limited. The composition of ensiled corn stover was also similar for all treatments examined. Biomass reactivity to pretreatment did not differ significantly for the ensiling treatments or the drying temperatures examined here. These results suggest that ensiling did not improve reactivity to pretreatment under the conditions tested. In this study, ensiling did effectively preserve corn stover over the course of long-term, wet storage. Subsequent studies will be performed to quantify achievable ethanol yields from simultaneous saccharification and fermentation of pretreated, ensiled samples relative to pretreated, native material.