非离子表面活性剂对生物丁醇发酵的影响

Effect of non-ionic surfactants on butanol production with Clostridium acetobutylicum ATCC 824

摘要:

传统的丙酮-丁醇发酵的产物浓度过低 (丁醇终浓度约为1.3 wt%)，导致后期分离成本过高，从而影响了该过程的经济性，限制了其工业化进程。本文研究了高添加量的小分子非离子表面活性剂对生物丁醇发酵的影响。以吐温80为例，实验表明，当表面活性剂添加量超过其临界胶束浓度后，丁醇发酵的终浓度会随着表面活性剂添加量的增加而增加。当添加量达到5 wt%时，丁醇终浓度可以达到1.6 wt%，远高于该菌种的抑制浓度 (0.8 wt%)。为阐明表面活性剂的作用机理，实验考察了吐温80对丁醇的增溶效应以及对发酵菌体表面亲疏水性的影响。结果表明，吐温80对丁醇的增溶效果很小，而对菌体表面的亲疏水性有较明显的影响。

Abstract:

The uneconomical product recovery caused by the low butanol concentration in acetone-butanol-ethanol (ABE) fermentation has been received much attention by researchers. In this work, the effect of small molecule non-ionic surfactants on biobutanol fermentation was evaluated, using laboratory stocks of Clostridium acetobutylicum ATCC 824. It was found that non-ionic surfactants caused a substantial increase in butanol production when additive amount was higher than 1 wt%. The butanol concentration reached up to 16.9 g/L with 5 wt% Tween 80 and 100 g/L glucose in feed in a 5 L fermenter, which was about twice higher than the inhibition limit concentration (8.3 g/L for laboratory stocks used in the experiment). The surfactants micelle solubilization and surfactants adsorption to cell surface was investigated. It showed that surfactants micelle solubilization capacity to butanol was limited and cell surface hydrophobicity was alternated due to surfactants adsorption.