Modular pathway engineering for enhanced production of para-aminobenzoic acid and 4-amino-phenylalanine in Escherichia coli via glucose/xylose co-utilization

The modularization of biosynthetic pathways is a promising approach for enhancing microbial chemical production. We have developed a co-utilization method with glucose and xylose substrates to divide metabolic pathways into distinct production and energy modules to enhance the biosynthesis of para-aminobenzoic acid (pABA) in Escherichia coli. Optimizing initial glucose/xylose concentrations and eliminating carbon leakage resulted in a pABA titer of 8.22 g/L (yield: 0.23 g/g glucose). This strategy was then applied to the biosynthesis of 4APhe, a compound synthesized from chorismate without pyruvate (PYR) release. Utilizing glucose and xylose as co-substrates resulted in the production of 4.90 g/L 4APhe. Although 4APhe production did not benefit from PYR-driven energy generation as pABA production did, high titer was still achieved. This study highlights the effectiveness of modular metabolic pathway division for enhancing the production of key aromatic compounds and provides valuable insight into microbial production of chemicals that require specific biosynthetic donors such as amino groups.