High strength vinegar fermentation by Acetobacter pasteurianus via enhancing alcohol respiratory chain

Seeking high strength vinegar fermentation by acetic acid bacteria (AAB) is still the mission of vinegar producers. AAB alcohol respiratory chain, located on intracellular membrane, is directly responsible for vinegar fermentation. In the semi-continuous vinegar fermentation by Acetobacter pasteurianus CICIM B7003, acetification rate showed positive correlation with the activity of the enzymes in alcohol respiratory chain. Aiming at achieving high strength fermentation process, a series of trials were designed to raise the activity of AAB alcohol respiratory chain. Finally, acetification was enhanced by adding some precursors (ferrous ions and beta-hydroxybenzoic acid) of alcohol respiration associated factors and increasing aeration rate (0.14 vvm). As final result, average acetification rate has been raised to 2.29 +/- 0.02 g/L/h, which was 28.7% higher than the original level. Simultaneously, it was found that the oxidization of alcohol into acetic acid in AAB cells was improved by well balancing of three factors: enzyme activity in alcohol respiratory chain, precursor of ubiquinone biosynthesis, and aeration rate.