Isolation and characterization of acetic acid bacteria for producing “makgeolli seed-vinegar”

Acetic acid bacteria strains were isolated from commercial natural vinegar. Ten isolated strains were identified using 16S rRNA gene sequencing data after evaluating the ethanol- and sulfur-tolerance. Eight of the strains isolated were identified as Acetobacter pasteurianus. A. pasteurianus JAC002, JAC005, and JAC008 strains, which showed a high ethanol tolerance, were selected for making “Makgeolli seed-vinegar”. Rice wine vinegars were manufactured with the selected strains through fermentation, and their physicochemical properties and antimicrobial activities were evaluated. A. pasteurianus JAC002 strain showed the highest oxidation ability to acetic acid from ethanol on the twentieth day of fermentation, resulting in 4.21% total acidity, 3,791.77 mg% acetic acid content, and 2,931.78 mg% ethanol consumption content. Rice wine vinegar manufactured with the A. pasteurianus JAC002 strain showed increased antimicrobial activities against Staphylococcus aureus (KACC1927) and Escherichia coli (KACC10115). As a result, A. pasteurianus JAC002 strain was found to be the most suitable strain for “Makgeolli seed-vinegar”.