Parallel metabolic pathway engineering for aerobic 1,2‐propanediol production in Escherichia coli

Abstract

The demand for the essential commodity chemical 1,2‐propanediol (1,2‐PDO) is on the rise, as its microbial production has emerged as a promising method for a sustainable chemical supply. However, the reliance of 1,2‐PDO production in Escherichia coli on anaerobic conditions, as enhancing cell growth to augment precursor availability remains a substantial challenge. This study presents glucose‐based aerobic production of 1,2‐PDO, with xylose utilization facilitating cell growth. An engineered strain was constructed capable of exclusively producing 1,2‐PDO from glucose while utilizing xylose to support cell growth. This was accomplished by deleting the gloA, eno, eda, sdaA, sdaB, and tdcG genes for 1,2‐PDO production from glucose and introducing the Weimberg pathway for cell growth using xylose. Enhanced 1,2‐PDO production was achieved via yagF overexpression and disruption of the ghrA gene involved in the 1,2‐PDO‐competing pathway. The resultant strain, PD72, produced 2.48 ± 0.15 g L−1 1,2‐PDO with a 0.27 ± 0.02 g g−1‐glucose yield after 72 h cultivation. Overall, this study demonstrates aerobic 1,2‐PDO synthesis through the isolation of the 1,2‐PDO synthetic pathway from the tricarboxylic acid cycle.