Search

In this work, the acetone-butanol-ethanol (ABE) fermentation was upgraded in order to improve its economy. Fed-batch fermentation was integrated with two-stage gas stripping-pervaporation unit. The permeated ABE condensate was used as substrate for oleates production. Candida sp. 99–125 cells, being rich in lipase activity, were used as full-cell catalyst. Different ABE feeding strategies in the esterification process were compared. As results, 10.1%, 68.6% and 72.5% of butyl oleate were obtained in the one-step added scenario, the stepwise-added scenario, and the simultaneous fed-batch scenario, respectively. The novel hybrid process was energy-saving, environmentally friendly and profitable, showing promise in future industrialization. [ABSTRACT FROM AUTHOR]

• Fed-batch SSF-membrane integration process was performed for LA production. • Cellulase was recycled by the integrated process and reused in following operations. • Nutrients and wastewater discharge were significantly reduced in the process. • LA yield of 0.389 g g−1 was obtained using the recycling the waste streams. • Wastewater and cellulase cost were reduced by 73.7 % and 47.4 %. In order to overcome bottlenecks of the high amount of cellulase consumption in lignocellulosic l -Lactic acid (LA) production, a non-sterilized fed-batch simultaneous saccharification and fermentation (SSF) -membrane separation integration process was established in this current work. During the process, residual cellulase that remaining in the waste aqueous solution and solid residuals of corn stover (CS) were recycled and reused in subsequent fermentations. A total 6 rounds of operation were performed. Averagely, LA yield of 0.389 g g−1 (pretreated CS) was achieved, which was 1.20 times higher than that of the conventional process without waste stream recycling. Moreover, the wastewater discharge and the cost of nutrients for fermentation can also hugely decrease. Results indicated that cellulase, wastewater discharge and nutrients consumption of the process reduced by 47.4 %, 73.7 % and 86.1 %, respectively. This study opens a promising way for the reduction of second-generation LA production cost, which could significantly change the economic feasibility of the LA biorefineries. [ABSTRACT FROM AUTHOR]