关键词: 通气, 氧化还原电位, 木质纤维素, 抑制物, 发酵

Abstract:

The effect of ORP regulation on batch fermentation by Kluyveromyces marxianus 1727-5 was investigated using glucose, xylose and glucose/xylose mixture under stress conditions caused by mixture of acetic acid, formic acid, furfural and 5-HMF. Moreover, batch fermentation from corn stalk hydrolysate was further conducted with the optimized ORP control strategy. The experimental results showed that the stress tolerance of cells to multiple inhibitors above was significantly improved together with enhanced cellular metabolic activities involved in both glucose and xylose utilization. For the fermentation from glucose/xylose mixture, the significant improvements were also achieved with respects to xylose utilization under ORP control conditions. Especially, with ORP controlled at -150 mV, the glucose fermentation time was shortened about 30% with the same ethanol. The yields of xylitol was increased from 3 g·L^-1 to 10 g·L^-1 compared to the control without ORP regulation. More important, when the ORP controlled at -100 mV, fermentation from corn stalk hydrolysate was greatly facilitated in terms of inhibitors tolerance, and the glucose fermentation time was shortened about 22% with the same ethanol. More important, xylose utilization and xylitol yield were increased to 10.27 g·L^-1 and 0.48 g·g^-1, respectively, compared to those of 4.88 g·L^-1 and 0.20 g·g^-1 in the control without ORP regulation.

Key words: aeration, ORP, lignocellulose, inhibitor, fermentation