Analysis of alcohol dehydrogenase activity and fermentation characteristics of Acetobacter pasteurianus JST-S strain

Alcohol dehydrogenase activity (ADH), acetic acid yield, and tolerance to temperature and acid-induced stress are important bacterial strain parameters for the industrial production of acetic acid or vinegar. In this study, we evaluated and compared multiple features between A. pasteurianus JST-S strain, screened in the laboratory, and A. pasteurianus CICC 20001, a commonly used industrial strain. The ADH enzyme activity peaked at 8.22 U mg⁻¹ for JST-S compared with the 7.62 U mg⁻¹ for CICC 20001. Further, the ADH protein level was higher in JST-S than in the CICC 20001 strain. Comparative analysis of growth and cell morphology of the two strains indicated that the acetic acid tolerance of JST-S is superior to that of CICC 20001. Further, when the two strains were used for semi-continuous fermentation in 4 batches, the total acid production in fermentation broth with the JST-S peaked at 62.96 ± 1.42 g L⁻¹ compared with 56.83 ± 1.12 g L⁻¹ for the CICC 20001 strain. Thus, the JST-S strain seems to have better fermentation characteristics than the commonly used industrial strain. Based on all our observations, we propose that A. pasteurianus JST-S may be applied for cost-effective industrial production to obtain a high concentration of acetic acid.