GLUCOSE TOLERANCE AS DISTINCTIVE TRAITS OF ACETIC ACID BACTERIA

Vinegar production as well other fermented foods and beverages is based on the use of starter cultures which permit a higher degree of control and standardisation of the final product compared to spontaneous fermentation. The first task to optimise fermented foods process is the knowledge of microorganism physiological and metabolic traits. Acetic acid bacteria species occurring in vinegar production are well known, but species monitoring and strains selection are not common procedures. Then there are not extensive studies on significant traits of strains involved in vinegar oxidation process. Concerning to traditional balsamic vinegars few researches are available about occurring species and their physiological traits. In this study strains isolated from traditional balsamic vinegar samples were investigated by enzymatic digestion of ITS1 regions using RsaI and HaeIII restriction endonucleases and by sequencing of 16S rDNA and ITS1 rDNA. Since elevated sugar concentration resistance and growing is an important trait for traditional balsamic vinegar acetic acid bacteria, the isolated strains were tested for glucose tolerance. On the basis of technological results glucose concentration is an acetic acid bacteria limiting-factor and Acetobacter malorum species is more resistant to high glucose concentration than other species occurred in balsamic vinegar.Keywords: acetic acid bacteria, glucose tolerance, strains selection