Construction of a Microbial Consortium for the De Novo Synthesis of Butyl Butyrate from Renewable Resources

Butyl butyrate has shown wide applications in food, cosmetic, and biofuel sectors. Currently, biosynthesis of butyl butyrate still requires exogenous addition of precursors and lipase, which increases the production cost and limits further large-scale development. In this study, a microbial consortium was first designed to realize direct butyl butyrate production from lignocellulose. The highest butyl butyrate concentration of 34.42 g/L was detected in the solvent phase from 60 g/L glucose using a microbial coculture system composed of Clostridium acetobutylicum NJ4 and Clostridium tyrobutyricum LD with the elimination of butyric acid supplementation. Meanwhile, 13.52 g/L butyl butyrate was synthesized from 60 g/L glucose using a microbial consortium composed of three strains including strain NJ4, strain LD, and Escherichia coli BL21- pET-29a(+)-LE without the addition of any exogenous precursors and lipase. In addition, 2.94 g/L butyl butyrate could be directly produced from 60 g/L microcrystalline cellulose when Trichoderma asperellum was added to the above-mentioned three-strain microbial consortium. This four-strain microbial consortium represents the first study regarding the direct butyl butyrate production from lignocellulose without the supplementation of exogenous precursors and lipase, which may be extended to the biosynthesis of other short-chain esters, such as ethyl acetate and butyl lactate.