Simultaneous saccharification and fermentation of lime-treated biomass

Simultaneous saccharification and fermentation (SSF) was performed on lime-treated switchgrass and corn stover, and oxidatively lime-treated poplar wood to determine their compatibility with Saccharomyces cerevisiae. Cellulose-derived glucose was extensively utilized by the yeast during SSF. The ethanol yields from pretreated switchgrass, pretreated corn stover, and pretreated-and-washed poplar wood were 72%, 62% and 73% of theoretical, respectively, whereas those from alpha -cellulose were 67 to 91% of theoretical. The lower ethanol yields from treated biomass resulted from lower cellulose digestibilities rather than inhibitors produced by the pretreatment. Oxidative lime pretreatment of poplar wood increased the ethanol yield by a factor of 5.6, from 13% (untreated) to 73% (pretreated-and-washed).