RESUMO
The low butanol concentration of acetone-butanol-ethanol fermentation causes uneconomical product recovery. In this work, the effect of small molecule non-ionic surfactants on butanol fermentation was evaluated, using laboratory stocks of Clostridium acetobutylicum ATCC 824. Non-ionic surfactants substantially increased butanol production when additive amount was higher than 1% (W/W). Butanol concentration reached 16.9 g/L with 5% (W/W) Tween 80 and 100 g/L glucose in a 5 L fermenter. It was found that surfactants micelle solubilization capacity to butanol was very limited, indicating that butanol could hardly enter the surfactants micelle. Butanol production improvement was probably caused by cell surface hydrophobicity change due to surfactants adsorption.