Construction of a “nutrition supply–detoxification” coculture consortium for medium-chain-length polyhydroxyalkanoate production with a glucose–xylose mixture

Abstract

Abstract In this study, we constructed a coculture consortium comprising engineered Pseudomonas putida KT2440 and Escherichia coli MG1655. Provision of “related” carbon sources and synthesis of medium-chain-length polyhydroxyalkanoates (mcl-PHAs) were separately assigned to these strains via a modular construction strategy. To avoid growth competition, a preference for the use of a carbon source was constructed. Further, the main intermediate metabolite acetate played an important role in constructing the expected “nutrition supply–detoxification” relationship between these strains. The coculture consortium showed a remarkable increase in the mcl-PHA titer (0.541 g/L) with a glucose–xylose mixture (1:1). Subsequently, the titer of mcl-PHA produced by the coculture consortium when tested with actual lignocellulosic hydrolysate (0.434 g/L) was similar to that achieved with laboratory sugars’ mixture (0.469 g/L). These results indicate a competitive potential of the engineered E. coli–P. putida coculture consortium for mcl-PHA production with lignocellulosic hydrolysate.