Abstract
Modular co-culture engineering is an emerging approach for biosynthesis of complex natural products. In this study, we constructed microbial co-cultures composed of two and three E. coli strains, respectively, for de novo biosynthesis of flavonoid acacetin, a value-added natural compound possessing numerous demonstrated biological activities, from simple carbon substrate glucose. To this end, the heterologous biosynthetic pathway was divided into different modules, each of which was accommodated in a dedicated E. coli strain for functional expression. After the optimization of the inoculation ratio between the constituent strains, the engineered cocultures showed a 4.83-fold improvement in production comparing to the mono-culture controls. Importantly, cultivation of the three-strain co-culture in shake flasks resulted in the production of 20.3 mg/L acacetin after 48 h. To our knowledge, this is the first report on acacetin de novo biosynthesis in a heterologous microbial host. The results of this work confirm the effectiveness of modular co-culture engineering for complex flavonoid biosynthesis.