Culture and function-related characteristics of six acetic acid bacterial strains isolated from farm-made fermented vinegars

Abstract

The present study evaluated the cultural and functional characteristics of six strains of acetic-acid bacteria (AAB), namely, GHUR-A11-2, SR-A24, GY-A26, GHF-A37, JS-B7, and JS-C1, which were isolated from farm-made fermented vinegars. The six bacterial strains exhibited high acetic acid production capability via the decomposition of CaCO3, and they were identified as Acetobacter pasteurianus based on the 16S rDNA sequences. The initial pH and optimal growth temperature for acetic acid production were determined to be 4.0 and 30℃, respectively; however, some strains of AAB presented reasonable growth even at 40℃. Four bacterial strains (except SR-A24 and GHF-A37) exhibited alcohol degradation activities of more than 90%. Bacillus cereus presented high susceptibility to the antibacterial activity of the six strains of AAB. The antioxidant activity evaluated using DPPH and ABTS was 5–15 times and 4–5 times higher for the six strains of AAB than that for the control group, respectively. GHUR-A11-2, SR-A24, and JS-C1 exhibited higher ACE activities, with inhibition rates of 154%-175%, as compared to those exhibited by the positive control of 0.1% captopril (inhibition rate of 138%). Furthermore, the fibrinolysis activity of SR-A24 (93.3%) was markedly higher than that of 0.5 U plasmin. Four bacterial strains (except GHF-A37 (75.3%) and JS-B7 (68.0%)), exhibited α-glucosidase inhibition activities of more than 100%. It was concluded that the six strains of AAB exhibited excellent physiologically active characteristics, which facilitated their use as seed strains for the synthesis of high-efficiency functional vinegar by harnessing the functional characteristics that fit the scientific basis.