1. An efficient 2-keto-L-gulonic acid whole-cell biotransformation system built on the characterization of L-sorbose dehydrogenase.
- Author
-
Li, Fan, Wang, Cai-Yun, Zhang, Meng-Yue, and Zhang, Yi-Xuan
- Subjects
- *
BIOCONVERSION , *SORBOSE , *DEHYDROGENASES , *FERMENTATION , *VITAMIN C - Abstract
• SDH_1927 has the highest specific activity (56.72 ± 1.2 U/mg) among the eight L-sorbose dehydrogenases. • The 2-KGA production can be significantly increase by PMS under the condition of avoiding light. • The product 2-KGA could inhibit SDH activity by competing for the same hydrogen bonding sites with the substrate of L-sorbose. • The cell-recycling catalysis system is proposed to convert L-sorbose to 2-KGA, with the yield of 80.12 g/L and the productivity of 6.68 g/L/h. There are five L-sorbose dehydrogenases (SDH_2764, SDH_2744, SDH_0718, SDH_1927, SDH_0337) in Ketogulonicigenium vulgare SPU B805 and three L-sorbose dehydrogenases (SDH_02251, SDH_02271, SDH_P100164) in K. robustum SPU_B003, which play essential roles in the classical two-step fermentation for 2-keto-L-gulonic acid (2-KGA, the precursor of vitamin C) synthesis. In this work, the above eight SDH enzymes were cloned and purified, and their optimal pH values and reaction temperatures, kinetic properties (K m and K cat), thermal stabilities, substrate spectra, and effects of metal ions were determined. Eight SDH-harboring recombinant E.coli strains were verified to be capable to catalyze L-sorbose to 2-KGA. Additionally, the molecular docking results showed that the product 2-KGA could inhibit SDH activity by competing for the same hydrogen bonding sites with substrate L-sorbose. Finally, a novel and efficient whole-cell recycling catalysis system to overcome the product inhibition was proposed, the yield of 2-KGA reached up to 80.12 g/L with the productivity of 6.68 g/L/h. The results provide a promising prospect for selection and modification sorbose dehydrogenase for construction a one-step biotransformation system of 2-KGA. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF