초록
<P><B>Highlights</B></P><P>► We use alkaline peroxide pretreated rapeseed straw for bioethanol production. ► Pretreatment at 50°C for 1h is enough for an efficient saccharification. ► Presence of MgSO<SUB>4</SUB> in pretreatment mixture affects delignification and ethanol yield. ► Co-fermentation efficiency and ethanol yield mostly depend on <I>Pichia stipitis</I> activity. ► Co-fermentation of pretreatment liquid will increase total ethanol yield.</P> <P><B>Abstract</B></P><P>Alkaline peroxide pretreatment of rapeseed straw was evaluated for conversion of cellulose and hemicellulose to fermentable sugars. After pretreatment, a liquid phase called pretreatment liquid and a solid phase were separated by filtration. The neutralized pretreatment liquids were used in a co-fermentation process, with <I>Saccharomyces cerevisiae</I> and <I>Pichia stipitis</I>. The solid fraction was used for simultaneous saccharification and co-fermentation process in the same vessel. The effects of various operating variables were investigated. Pretreatment with 5% (v/v) H<SUB>2</SUB>O<SUB>2</SUB> at 50°C for 1h was found to be the optimal pretreatment combination with respect to overall ethanol production. At this condition, 5.73g ethanol was obtained from pretreatment liquid and 14.07g ethanol was produced by co-fermentation of solid fraction with <I>P. stipitis</I>. Optimum delignification was observed when 0.5M MgSO<SUB>4</SUB> was included in the pretreatment mixture, and it resulted in 0.92% increase in ethanol production efficiency.</P>