Comparing E. coli mono-cultures and co-cultures for biosynthesis of protocatechuic acid and hydroquinone

Protocatechuic acid (PCA) and hydroquinone (HQ) are two important phenolic molecules with recognized biological activities and industrial values. In the present study, we constructed a series of E. coli mono-cultures and co-cultures for the PCA and HQ biosynthesis from simple carbon substrate glucose. Metabolic engineering strategies, include over-expression of key pathway enzymes and utilization of biosensor-assisted cell selection, were adapted to improve the pathway intermediate supply and the overall biosynthesis. The comparative analysis showed that the adapted strategies had different degrees of impacts on the biosynthesis performance of the constructed mono-cultures and co-cultures. The highest PCA and HQ bioproduction (641 and 303 mg/L, respectively) was achieved using the optimized co-culture. Our findings show that, compared with mono-cultures, rationally designed co-cultures provide a new perspective for application of advanced metabolic engineering strategies.