添加表面活性剂改善丁醇萃取发酵性能

Improvement of extractive fermentation performance of butanol by adding surfactacts into fermentation medium

研究了各种表面活性剂对丁醇萃取发酵的影响。丁醇发酵中有大量H2、CO2气体生成,生成的气泡携带发酵溶剂产物(丁醇、丙酮)进入萃取液相,促进了水相中发酵毒性产物向萃取液相的移动。研究发现,表面活性剂可以降低气-液膜的表面张力,促使大气泡破碎,从而使发酵产气以较小气泡的形式穿过萃取液相。添加表面活性剂可以强化发酵溶剂产物从水相到萃取相的移除速度,缩短发酵产物在油水两相中达到平衡的时间,有利于提高发酵生产强度。以地沟生物柴油为萃取剂,吐温-80的添加量为质量分数0.140%时,与对照相比(无表面活性剂的萃取发酵),相同发酵时间内萃取相中丁醇体积分数提高了21.2%,总溶剂生产强度也提高了16.5%。

The effect of surfactants on extractive fermentation of butanol was investigated. A large quantity of gas, such as hydrogen and carbon dioxide, was released in the process of butanol fermentation. The produced butanol and acetone were brought into the extractant phase by the releasing gas. As a result, the transfer of toxic products from aqueous phase to extractant phase was facilitated. Surfactants decreased the tension of gas - liquid interface and made the large bubble break down; Therefore, the releasing gas passed through the extractant phase in the form of small bubble. The mass transfer rate of products from the aqueous phase to the extractant phase was enhanced and the balance time was shortened accordingly by the addition of surfactants, consequently, the fermentation productivity was improved. Using waste cooking oil derived biodiesel as the extractant, the butanol concentration in extractant phase was increased by 21.2% contrasted with that of the control, in which no surfactant was added, while the concentration of surfactant（Tween-80） in culture medium was 0. 140% （w/v）. Under these conditions, gross solvent productivity was increased by 16.5%.