Production of butyl butyrate from lignocellulosic biomass through Escherichia coli-Clostridium beijerinckii G117 co-culture
Yonghao Cui, Xiaoqiang Ma, Song Han Lee, Jianzhong He, Kun‐Lin Yang, Kang Zhou
Abstract
Butanol toxicity, oxygen sensitivity, and high substrate cost limit wider applications of the traditional Clostridium acetone-butanol-ethanol (ABE) fermentation. In this study, a wild-type Clostridium beijerinckii strain was partnered with an engineered Escherichia coli strain to improve the ABE fermentation through a co-culture. Butanol and butyrate produced by C. beijerinckii were converted into butyl butyrate – a product that can be in situ removed to reduce product toxicity – by expressing a CoA transferase and an alcohol acyltransferase in E. coli. When integrated with a pretreatment technology and using commercial cellulase, the co-culture produced 1,280 mg/L butyl butyrate from rice straw in bioreactors, without the need of maintaining a strict anaerobic condition. As a process harnessing both the genetic tractability of E. coli and the superior acid- and alcohol-producing ability of Clostridium, this co-culture fermentation will be useful in producing valuable esters from low-cost waste streams.