Systematic metabolic engineering of Klebsiella oxytoca for production of 1,3-propanediol from glucose

The rising demand for the three-carbon diol 1,3-propanediol (1,3-PDO) in various industrial applications, including food, lubricants, drugs, and new polyester polymer materials, has spurred notable interest in development of environmentally sustainable processes. These processes aim to fulfill the increasing demand for 1,3-PDO while simultaneously addressing the climate and environmental issues linked to fossil-based chemical production. In this study, we successfully synthesized 1,3-PDO directly from glucose using a well-established safety strain Klebsiella oxytoca. We employed a systematic metabolic engineering strategy to enhance 1,3-PDO production, including screening glycerol synthesis pathways, blocking competing by-product biosynthetic pathways, increasing carbon flux towards 1,3-PDO synthesis, and replacing the glucose transport system. As a result, the engineered strain achieved a flask fermentation titer of 6.2 g L-1 1,3-PDO. These findings hold significant implications for future research on utilizing this strain for efficient bioconversion of glucose to 1,3-PDO.