Isolation and Characterization of Acetobacter Species from a Traditionally Prepared Vinegar

Abstract

Acetic acid bacteria (AAB) were isolated from vinegar fermented through traditional methods in Namhae county, Gyeongnam, the Republic of Korea. The isolated strains were Gram negative, non-motile, and short-rods. Three selected strains were identified as either Acetobacter pasteurianus or Acetobacter aceti by 16S rRNA gene sequencing. A. pasteurianus NH2 and A. pasteurianus NH6 utilized ethanol, glycerol, D-fructose, D-glucose, D-mannitol, D-sorbitol, L-glutamic acid and Na-acetate. A. aceti NH12 utilized ethanol, n-propanol, glycerol, D-mannitol and Na-acetate. These strains grew best at 30 o C and an initial pH of 3.4. They were tolerant against acetic acid at up to 3% of initial concentration (v/v). The optimum conditions for acetic acid production were 30 o C and pH 3.4, with an initial ethanol concentration of 5%, resulting in an acetic acid concentration of 7.3�7.7%.