Anaerobic fermentation of pretreated food waste for butanol production by co-cultures assisted with in-situ extraction

Abstract

Acetone-butanol-ethanol (ABE) fermentation is a promising technology for butanol production, while it is hampered by the high cost of substrate and low butanol titer. To improve the butanol production of food waste, the influence of three technologies including pretreatment of food waste, co-culture fermentation and in-situ extraction on ABE fermentation was investigated. Bath fermentation indicated that the enzymatic pretreatment was the preferable approach for food waste hydrolysis, and the corresponding butanol titer was 1.5 g/L. With the optimum Clostridium acetobutylicum / Clostridium pasteurianum strains’ ratio of 7:3, the butanol production of food waste was improved to 3.1 g/L. The combination of the three technologies further increased the butanol titer to 12.5 g/L in the in-situ extraction system. The alleviation of inhibitory effect caused by butanol and butyrate explained the high butanol titer. This study demonstrated that there was a great potential for the cost-effective butanol production from food waste.