Bioethanol production from alkali-pretreated sugarcane tops by optimized saccharification and microbial consortium fermentation
摘要
In this study, saccharification of alkali pretreated sugarcane tops biomass and its fermentation was optimized. The saccharification of alkali pretreated sugarcane tops carried out in 20 mL volume gave optimized conditions, 3%, w/v alkali pretreated sugarcane tops, 35 Filter Paper Unit/g of alkali pretreated sugarcane top of commercial enzyme and 48 h, at pH 4.5 and 45 °C giving 67.2%, w/w cellulose conversion with 18.6 g/L total reducing sugars. These optimized conditions used for higher scale saccharification at 3.6 L taking 120 g alkali pretreated sugarcane tops resulted in 68.7% (w/walkali pretreated sugarcane tops) cellulose conversion with 18.8 g/L total reducing sugars. Fermentation of above saccharified hydrolysate containing total reducing sugars (15 g/L) supplemented with 3 g/L yeast extract and 5% (v/v) consortium of fermenting yeasts (Saccharomyces cerevisiae, Pichia stipitis and Pachysolen tannophilus, 1:1:1 with each 107 Colony Forming Units/mL) carried out for 48 h at initial pH 5, 100 rpm and 35 °C in 20 mL gave 7.6 g/L of bioethanol. Same fermentation conditions used at higher scale in 5 L bioreactor at 3 L working volume gave 7.4 g/L of bioethanol within 24 h with 97% fermentation efficiency.
Graphical abstract