ORP调控对葡萄糖和果糖混合底物丁醇发酵的影响

Butanol production from mixture of glucose and fructose with ORP control

采用氧化还原电位(oxidoreduction potential,ORP)调控以模拟菊芋块茎酸解液(葡萄糖和果糖混合糖)为底物进行的丙酮丁醇发酵过程,能够有效控制"酸崩溃"现象的发生。已通过实验确定最佳调控策略为控制整个发酵过程的ORP不低于-460mV。本研究在最佳调控策略下,发酵终点丁醇浓度从3.39g/L提高到11.65g/L,残糖浓度从30.82g/L降低到1.38g/L。对比ORP调控组和对照组发现,ORP调控能够改变发酵过程中细胞内还原力水平,能量状态和代谢流向,因此ORP调控能有效防止"酸崩溃"现象发生,调节菌体生长和溶剂产量。ORP调控策略应用于以葡萄糖和果糖混合糖为底物的丁醇发酵具有操作可行性,是一种简便而有效的工艺优化手段。

The effects of oxidoreduction potential （ORP） control on batch acetone butanol ethanol （ABE） fermentation by Clostridium acetobutylicum L7 from the mixture of glucose and fructose to stimulate the hydrolysate of Jerusalem artichoke tuber were investigated.It was found that ORP control significantly contributed to the relief of ‘acid crash’ phenomenon existing in the uncontrolled fermentation process.ORP control could facilitate the transition from acidogenesis to solventogenesis effectively.Controlling ORP level above-460mV was proven to be the best ORP control strategy.Under this condition,butanol titer increased from 3.39g/L to 11.65g/L with residual sugars decreasing from 30.82g/L to 1.38g/L.Comparative analysis showed that under the optimized ORP control condition,the intracellular reducing equivalents,energy state and metabolic flux were significantly redistributed,which thus resulted in no ‘acid crash’ and enhanced cell growth as well as solvents titers.The optimized ORP control strategy was demonstrated to be cost effective.