Microbiological Aspects of Acetate Oxidation by Acetic Acid Bacteria, Unfavorable Phenomena in Vinegar Fermentation

Abstract

Several strains of acetic acid bacteria belonging to the genus Acetobacter, showing strong acetate oxidation, were screened and their microbiological aspects in acetate oxidation were investigated. When all available carbon and energy sources were exhausted and only acetic acid remained in the late stationary phase, the bacteria started to consume the acetic acid that had been accumulated in the culture medium for vinegar fermentation. They grew rapidly, showing the second stationary phase and a typical biphasic growth curve was observed. The cells from the first growth phase were acid tolerant, while the cells from the second growth phase turned over to become acid sensitive. However, no distinct acetate oxidation took place when oxidizable ethanol and other available carbon sources still remained in the culture medium. Moreover, no apparent acetate oxidation was observed in vinegar mash in which more than 4.5% of acetic acid was allowed to accumulate. There was a threshold in acetate concentration since...