Achieving high strength vinegar fermentation via regulating cellular growth status and aeration strategy

Implementing of high strength vinegar fermentation is still the mission of vinegar producers. The aim of this study was to carry out high acidity vinegar fermentation efficiently based on comprehensive analysis on bacterial fermentation kinetics characteristics of Acetobacter pasteurianus CICIM B7003-02. In practice, semi-continuous vinegar fermentation was optimized with an optimal discharge/charge ratio of 34% of working volume (v/v), which resulted in a proper growth status of Acetobacter and beneficial to acetification. Then, a two-stage aeration protocol was adopted in the vinegar fermentation in line with the Acetobacter theoretical oxygen demand, by which both vinegar stoichiometric yield and acetification rate were improved effectively. As the final result, a titer of 93.09 ± 0.24 g/L acetic acid was achieved, the average acetification rate was enhanced to a level of 1.83 ± 0.01 g/L/h, and the vinegar stoichiometric yield was promoted to 93.97 ± 0.16%. The strategy and practice worked out from this study provided a valuable reference for performing large scale vinegar fermentation with higher strength.