Search

[Display omitted] • Liquid fraction containing glycerol was used for recycled corn stover pretreatment. • Dry cell weight of P. pastoris reached ∼ 40 g/L with glycerol as sole carbon source. • The titer of human lysozyme reached 1.3 g/L by P. pastoris with methanol induction. • Mixing pretreated corn stover with cassava as co-substrate to produce biobutanol. • Final butanol titer of 13.9 g/L was produced from mixed substrates under SSF. Glycerol organosolv pretreatment (GOP) is considered an efficient method to deconstruct lignocellulose for producing fermentable sugars. Herein, the liquid fraction containing glycerol after GOP was utilized for recycled pretreatment of corn stover (CS) for four cycles. Enzymatic yield of glucose after recycled pretreatment was enhanced by 2.4–3.5 folds compared with untreated CS. Meanwhile, residual glycerol was used as carbon source for cultivation of Pichia pastoris to obtain high cell-density, and a final titer of 1.3 g/L human lysozyme was produced by P. pastoris under low temperature methanol induction strategy. Additionally, the pretreated CS was mixed with cassava as fermentable substrates for butanol production by wild-type Clostridium acetobutylicum ATCC 824. Final butanol production of 13.9 g/L was obtained from mixed substrates (25%:75% of CS/cassava) at 10% solids loading by simultaneous saccharification and fermentation. Overall, integration of residual glycerol utilization and butanol production by microbial fermentation provided an efficient strategy for biorefinery. [ABSTRACT FROM AUTHOR]

[Display omitted] • Glycerol organosolv pretreatment could efficiently deconstruct corn stover. • The yield of glucose/xylose reached ∼80 % with glycerol pretreatment by cellulase. • l -cysteine-assisted glycerol pretreatment was developed for enhanced enzymolysis. • Fermentable sugars production reached 26.08 g/100 g by the proposed pretreatment. • Effects of raw materials prices on economic feasibility of processes were studied. Deconstruction of lignocellulose via efficient pretreatment is crucial for producing fermentable sugars. In this study, effects of glycerol organosolv pretreatment (GOP) on main chemical composition of corn stover were investigated. Results indicate that the residual corn stover after 80 wt% glycerol pretreatment (at 220 °C for 0.5 h) yielded 75.97 % glucose and 78.21 % xylose after enzymatic hydrolysis, which were enhanced by 3.39- and 6.08-fold compared to the untreated corn stover. Subsequently, an l -cysteine-assisted GOP was proposed with higher yields of glucose (86.20 %) and xylose (91.13 %). When pretreating corn stover with 80 wt% glycerol containing 0.07 wt% l -cysteine at 220 °C for 0.5 h, higher fermentable sugars of 26.08 g were produced from 100 g feedstock after enzymolysis. Intrinsic mechanisms of the proposed pretreatment for enhancing enzymatic digestibility were elucidated by physiochemical characterization technologies and techno-economic analysis was also studied. This study provides guidance for fermentable sugars production from renewable lignocellulose. [ABSTRACT FROM AUTHOR]