Simultaneous utilization of glucose and xylose by metabolically engineered Pseudomonas putida for the production of 3-hydroxypropionic acid

Pseudomonas putida, a robust candidate for lignocellulosic biomass-based biorefineries, encounters challenges in metabolizing xylose. In this study, Weimberg pathway was introduced into P. putida EM42 under a xyloseinducible promoter, resulting in slow cell growth (0.05 h-1) on xylose. Through adaptive laboratory evolution, an evolved strain exhibited highly enhanced growth on xylose (0.36 h-1), comparable to that on glucose (0.39 h-1). Whole genome sequencing identified four mutations, with two key mutations located in PP3380 and PP2219. Reverse-engineered strain 8EM42_Xyl, harboring these two mutations, showed enhanced growth on xylose but co-utilizing glucose and xylose at a rate of 0.3 g/L/h. Furthermore, 8EM42_Xyl was employed for 3-hydroxypropionic acid (3HP) production from glucose and xylose by expressing malonyl-CoA reductase and acetyl-CoA carboxylase, yielding 29 g/L in fed-batch fermentation. Moreover, the engineered strain exhibited promising performance in 3HP production from empty palm fruit bunch hydrolysate, demonstrating its potential as a promising cell factory for biorefineries.