Biosynthesis of High Molecular Weight Poly(3-hydroxybutyrate) by Wild-Type Cupriavidus necator H16 Using Sugar Acids as the Carbon Source

This study investigated whether pectin-derived sugar acids can serve as effective carbon sources for poly(3-hydroxybutyrate) [P(3HB)] production in Cupriavidus necator H16. We attempted to utilize sugar acids, including glucuronic, galacturonic, and gluconic acids, as the carbon sources for the biosynthesis of polyhydroxyalkanoate (PHA) by wild-type Cupriavidus necator H16. Among the three types of sugar acids tested, only gluconic acid was used as the carbon source for PHA production. When cultivated on gluconic acid at a controlled pH, C. necator produced significantly higher biomass, increased P(3HB) accumulation, and elevated polymer molecular weight compared with fructose-grown cultures. The resulting P(3HB) exhibited enhanced mechanical strength and crystallinity, demonstrating the material advantages of utilizing gluconic acid. These findings demonstrate the potential of gluconic acid as a viable substrate for the production of high-quality P(3HB).