Efficient 1,3-dihydroxyacetone biosynthesis in Gluconobacter oxydans using metabolic engineering and a fed-batch strategy

Abstract

Abstract 1,3-Dihydroxyacetone (DHA) is a commercially important chemical and widely used in cosmetics, pharmaceuticals, and food industries as it prevents excessive water evaporation, and provides anti-ultraviolet radiation protection and antioxidant activity. Currently, the industrial production of DHA is based on a biotechnological synthetic route using Gluconobacter oxydans. However, achieving higher production requires more improvements in the synthetic process. In this study, we compared DHA synthesis levels in five industrial wild-type Gluconobacter strains, after which the G. oxydans WSH-003 strain was selected. Then, 16 dehydrogenase genes, unrelated to DHA synthesis, were individually knocked out, with one strain significantly enhancing DHA production, reaching 89.49 g L−1 and 42.27% higher than the wild-type strain. By optimizing the culture media, including seed culture and fermentation media, DHA production was further enhanced. Finally, using an established fed-batch fermentation system, DHA production reached 198.81 g L−1 in a 5 L bioreactor, with a glycerol conversion rate of 82.84%. Graphical Abstract

Keywords

• Gluconobacter oxydans
• 1,3-Dihydroxyacetone
• Metabolic engineering
• Dehydrogenase genes
• Fed-batch fermentation