Biodiversity Of Acetic Acid Bacteira In The Vinegar Pei Of Zhenjiang Aromatic Vinegar And The Propetries Of Gluconacetobacter Intermedius

Zhenjiang aromatic vinegar is known as one of the four famous Chinese vinegars, whichtaking the traditional spontaneous mixed-culture solid state fermentation process. Zhenjiangaromatic vinegar fermentation includes three steps: alcohol fermentation, acetic acidfermentation and later processing, the acetic acid fermentation process is a key step for thesuccess of vinegar fermentation. In our previous works, we have used PCR-DGGE, clonelibrary analysis, and pure-culture method to study the biodiversity of the microbial during theacetic acid fermentation stage, and found that acetic acid bacteria (AAB), lactic acid bacterial,Bacillus, and Paenibacillus co-present in the vinegar Pei, and found that AAB are the mainfunctional microbes during the fermentation process, which can convert ethanol and smallmolecule carbohydrate into acetic acid, thus forming the main vinegar flavor. While, thegenus diversity of AAB in the vinegar Pei of Zhenjiang aromatic vinegar currently lacksresearch. In this study, pure culture method was used to study the diversity of AAB in thevinegar Pei of Zhenjiang aromatic vinegar, and the metabolic characteristics ofGluconacetobacter intermedius were studied.A total of75presumed AAB strains were isolated from the vinegar Pei, and according tophysiological and biochemical tests and ERIC-PCR study, we found that those AAB strainsshown great diversity both in phenotype and genotype.35presumed AAB strains were selectto identify to species level by16S rDNA sequencing based on a combination of phenotypicand genotypic approaches including ERIC-PCR, restriction fragment length polymorphism(RFLP) analysis, they belong to genus Acetobacter and genus Gluconacetobacter, a total offour kinds of species:22strains A. pasteuriansu,5strains A. pomorum,5strains G.intermedius, and3strains G. xylinus. Among those AAB strains, G. intermedius was isolatedfrom the vinegar Pei of Zhenjiang aromatic vinegar for the first time.In this work, the shake-flask metabolic characteristics of G. intermedius were studied, thestrains were able to produce large amount of acetic acid, gluconic acid, and some flavorsubstances like acetoin, G. intermedius was a functional microorganism during the acetic acidfermentation of Zhenjiang aromatic vinegar. Furthermore, G. intermedius has better ability toproduce bacterial cellulose, which has potential research and application value. The effects oftemperature, culture time, carbon source, nitrogen source, and initial pH on the synthesis ofbacterial cellulose were studied using single factor experiments, the yield of bacteria cellulosewas improved from initial3.90±0.08g L-1to8.10±0.19g L-1under the optimal conditions.Real-time quantity PCR (RT-qPCR) was used to study the biomass and dynamic changesof G. intermedius during the acetic acid fermentation and sealed vinegar Pei process. Thebiomass of G. intermedius reached the higest at the5th day, which was2.91×105copies g-1dry Pei. While, a rapid increase at the seald vinegar Pei stage, and at the7th day, the biomassreached6.95×106copies g-1dry Pei.