The enhancement of ethanol production from NaOH-catalyzed organosolv pretreated poplar with compound additives

Abstract

In this study, different additives (such as Bovine serum albumin (BSA), PEG 8000, calcium lignosulfonate, tea saponin, and Tween 80) were introduced to enhance the efficiency of simultaneous saccharification and fermentation (SSF) of NaOH-catalyzed organosolv pretreated poplar. Then the influence of two-factor additive compound on SSF was determined, only 75 mg/g BSA had a positive interaction with 150 mg/g tea saponin, which generated the maximal ethanol yield of 92.83 % with ethanol concentration of 18.82 g/L after 24 h, ascribing to the higher relative enzyme activity, free enzyme, and Zeta potential. Furthermore, with the addition of combined additives at an enzyme dosage of 8 FPU/g substrate, the NaOH-catalyzed organosolv pretreated poplar liberated higher ethanol than that without additive at an enzyme dosage of 15 FPU/g substrate. This phenomenon indicated that the use of combined additive can improve fermentation efficiency, while reducing almost 1/2 enzyme dosage. In general, this study provided a facile and efficient method for ethanol production with compound additives.