Characterization and Culture Optimization of an Glucosidase Inhibitor-producing Bacteria, Gluconobactor oxydans CK-2165

Abstract Miglitol, a well-known therapeutic intervention agents for diabetes, exhibits competitive inhibitory activityagainst α-glucosidase and it is usually produced through three sequential steps including chemical and bioconversionprocesses. Gluconobactor oxydans ( G. oxydans ) belonging to acetic acid bacteria biologically, converts 1-deoxy-1 -(2-hydroxyethylamino)-D-glucitol (P1) into a key intermidiate, 6-(2-hydroxyetyl) amino-6-deoxy-α-L-sorbofuranose (P2) by incomplete oxidation. In this study, we identified and optimized fermentation conditions of CK-2165, that was selected in soil samples by comparing the bioconversion yield. CK-2165 strain was found to be closely relatedto G. oxydans based on the result of phylogenetic analysis using 16S rDNA sequence. Utilization of API 20 kits revealed that this strain could use glucose, mannose, inositol, sorbitol, rhamnose, sucrose, melibiose, amygdalin andarabinose as carbon sources. The culture conditions were optimized for industrial production and several important factors affecting bioconversion rate were also tested using mycelial cake. Cell harvested at the late-stationary phaseshowed the highest bioconversion yield and MgSO