Screening of Dominant Acetic Acid Bacteria in Raw Material Vinegar and Acid-production Characteristics

Acid-producing bacteria were screened from raw vinegar. The isolate and purified strain was identified as Acetobacter pasteurianus by morphological and 16S rDNA. Based on the number of colonies calculated by the colony counter and the type and amount of acid produced by high-performance liquid chromatography,the growth curve and acid production curve were drawn. The results showed that the biomass of A. pasteurians reached its maximum at 16 h. Among the organic acids produced in the fermentation process,the mass concentration of lactic acid was the highest,reached 2.1 mg/mL,and the acetic acid content reached 1.8 mg/mL during 116 h of fermentation. The mass concentration of oxalic acid was the lowest,range from 0.4 to 1.23 mg/100 mL.There was no significant change in the mass concentration of citric acid,which remained between 0.08 and 0.11 mg/mL.During the fermentation,the mass concentration of succinic acid increased from 0.04 mg/mL to 0.31 mg/mL,which mainly played a role in regulating the taste. The purpose of this study was to provide data reference for the quality evaluation of raw vinegar.