Enzymes Responsible for Acetate Oxidation by Acetic Acid Bacteria

Several acetic acid bacteria of the genus Acetobacter oxidize much acetate oxidation, which is not desired in vinegar manufacturing. Acetobacter rancens SKU 1111, a strong acetate oxidant, grew rapidly with a biphasic growth curve while consuming acetate in the second growth phase. Acetobacter aceti IFO 3284 did not show extensive acetate oxidation. Addition of glycerol to the culture medium of Acetobacter rancens SKU 1111 increased acetate oxidation and resulted in more biomass in the second growth phase than when glycerol was not added. Enzyme activities of acetyl-CoA synthetase and phosphotransacetylase in the organism were high during acetate oxidation. The activity of phosphoenolpyruvate carboxylase was most stimulated by a trace amount of acetyl-CoA among the enzymes of glycerol catabolism. Phosphoenolpyruvate carboxylase in A. rancens SKU 1111 showed a sigmoidal saturation curve with acetyl-CoA. This finding suggested that strong acetate oxidation caused by acetyl-CoA synthetase or phosphotransacetylase activity, together with phosphoenolpyruvate carboxylase, increased the biomass.