Vinegar producing is one of the oldest processes of biotechnology. It consists of double fermentation, alcoholic and acetous. There are three groups of methods of acetous fermentation: surface, trickling and submerse. They are well elaborated from technological and technical points of view, but the taxonomy and methods for identification of the bacteria active in technical processes are still open. According in the results of molecular researches, the new genus Gluconacetobacter (characterised by requirement of the acetic acid for growing and lack of ability to oxidise acetic acid to CO2 and H2O - the main features of genus Acetobacter) was separated from acetic acid bacteria group. However, the results of few experiments showed that these phenotypic features (characteristic for the genus Gluconacetobacter) could be changed in to the features characteristic for genus Acetobacter by special procedure of growing. It is a question of how the differences between the same bacteria with different phenotypes would be identified by molecular methods.