Abstract:The polymerase chain reaction/denaturing gradient gel electrophoresis (PCR-DGGE) was used to explore the diversity and change in dynamics of the bacterial communities during AAF of TDMV. In particular, the bacterial communities in the vinegar pei from the top and bottom layers were compared. Thirteen genera of bacteria were detected in the vinegar pei of the two layers. Although only the vinegar pei in the upper layer was stirred manually every day during the production process, the two layers of pei still belonged to the same system and the bacterial compositions were consistent, but there were differences in the diversity of the bacterial communities in the two layers. Using cluster analysis, the bacterial compositions were divided into two groups: the first stage and the second stage. According to the Shannon index, the diversity of bacteria from the first stage was higher than that of the second stage, and the diversity of bacteria in the upper layer was slightly higher than that of the bottom layer. The abundance of Acetobacter pasteurianus, the main microorganism converting ethanol to acetic acid in the AFF, increased gradually during the fermentation process and reached a peak value at the end of the fermentation. The abundance of some lactic acid bacteria (LAB), including Lactobacillus plantarum and Lactobacillus acetotolerans, increased gradually over the fermentation time, likely as a result of their high acid tolerance.
