Metabolic Engineering of Zymomonas mobilis for Acetoin Production by Carbon Redistribution and Cofactor Balance

Biorefinery to produce value-added biochemicals offers a promising alternative meet our sustainable energy and environmental goals. Acetoin is widely used in the food cosmetic industries as taste fragrance enhancer. The generally regarded safe (GRAS) bacterium Zymomonas mobilis produces acetoin an extracellular product under aerobic conditions. In this study, metabolic engineering strategies were applied including redistributing carbon flux manipulating NADH levels. To improve level, heterologous pathway was first introduced into Z. mobilis, which contained genes encoding acetolactate synthase (Als) decarboxylase (AldC) driven by strong native promoter Pgap. Then gene water-forming oxidase (NoxE) for cofactor balance. recombinant strain containing both artificial operon noxE greatly enhanced production with maximum titer reaching 8.8 g/L productivity of 0.34 g∙L−1∙h−1. addition, delete ndh redox balance I-F CRISPR-Cas system redirect from ethanol biosynthesis through dcas12a-based CRISPRi targeting pdc laid foundation help construct producer future. This study thus provides informative strategy method harness levels biorefinery synthetic biology studies mobilis.