Production of 1,4‐Butanediol from Succinic Acid Using Escherichia Coli Whole‐Cell Catalysis

Abstract The widespread attention towards 1,4‐butanediol (BDO) as a key chemical raw material stems from its potential in producing biodegradable plastics. However, the efficiency of its biosynthesis via current bioprocesses is limited. In this study, a dual‐pathway approach for 1,4‐BDO production from succinic acid was developed. Specifically, a double‐enzyme catalytic pathway involving carboxylic acid reductase and ethanol dehydrogenase was proposed. Optimization of the expression levels of the pathway enzymes led to a significant 318 % increase in 1,4‐BDO titer. Additionally, the rate‐limiting enzyme Mm CAR was engineered to enhance the k cat /K M values by 50 % and increase 1,4‐BDO titer by 46.7 %. To address cofactor supply limitations, an NADPH and ATP cycling system was established, resulting in a 48.9 % increase in 1,4‐BDO production. Ultimately, after 48 hours, 1,4‐BDO titers reached 201 mg/L and 1555 mg/L in shake flask and 5 L fermenter, respectively. This work represents a significant advancement in 1,4‐BDO synthesis from succinic acid, with potential applications in the organic chemical and food industries.