Heterologous expression and characterization of the carveol dehydrogenase from Klebsiella sp. O852

Abstract

Carvone has been widely used in pharmaceutical, food, cosmetic, and chemical industries due to its pleasant odor with high economic value and pharmacological activities. Carveol dehydrogenase is an enzyme that catalyzes the oxidation of carveol into carvone in the presence of NAD(P)+. In this study, two dehydrogenase genes from Klebsiella sp. O852 (KlebADH1 and KlebADH2) were cloned and expressed in Escherichia coli BL21(DE3), and the purified enzymes were characterized for their biocatalytic properties. KlebADH1 and KlebADH2 displayed optimal catalytic activity at 40 °C and 30 °C, respectively, at pH 9. In addition to carveol, KlebADH1 had the potential to catalyze the oxidation of perillyl alcohol, nerol and geraniol, while borneol and geraniol could serve as potential substrates for KlebADH2. The substrate kinetic parameters of enzymes were performed by changing the concentration of carveol, and the results indicated that KlebADH2 exhibited a high affinity for carveol. Additionally, KlebADH1 and KlebADH2 were confirmed to possess carveol dehydrogenase activity through a double-enzyme-coupled (DEC) biotransformation system. The investigation of the biocatalytic properties of KlebADH1 and KlebADH2 laid a solid foundation for further study of carvone sustainable synthesis.