Targeting metabolic driving and minimization of by-products synthesis for high-yield production of D-pantothenate in Escherichia coli.

Abstract

d-Pantothenate (DPA) is an important functional chemical that has been widely applied in healthcare, cosmetics, animal food, and feed industries. In this study, a high-yield DPA-producing strain was constructed by metabolic engineering strategies with targeting metabolic driving and by-products minimization. The metabolic driving force of push and pull was firstly obtained to improve the production of DPA via enrichment of precursor pool and synthetic pathway, accumulating 4.29gL-1 DPA in shake flask fermentation. To eliminate the metabolic pressure on DPA production, an amino throttling system was proposed and successfully attenuated the synthesis of four competitive amino acids by a single-step regulation of gdhA. Further minimization of acetate was carried out by pta deletion, and utilization of β-alanine was improved via enhancing its uptake system with producing 5.78gL-1 DPA. Finally, the engineered strain produced 66.39gL-1 DPA with β-alanine addition in fermentor under fed-batch fermentation. This study paved a foundation for the industrial production of DPA.