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Twenty fructophilic isolates from the stomachs of honeybee Apis mellifera ligustica from the region of Plovdiv, Bulgaria were obtained. Fructophilic isolates H3 and H25 showed formation of mucous colonies during cultivation on medium with sucrose, suggesting exopolysaccharide synthesis. The sequencing analysis of 16S rRNA identified isolates H3 and H25 as fructophilic lactic acid bacteria Lactobacillus kunkeei. The in situ analysis and periodic acid-Schiff's staining, showed that Lb. kunkeei H3 and H25 produce extracellular glucansucrases with molecular weight of about 300 kDa. In the cell-associated fractions, additional glucansucrase is detected with molecular weight of about 180 kDa. The content of α-(1 → 6) linkages in the glucans synthesized with extracellular glucansucrases from H3 and H25 after dextranase hydrolysis was significantly lower than this one of the classical dextran - about 35 and 62%, respectively. These results suggest a more branched structure of the studied polymers. [ABSTRACT FROM AUTHOR]

The article reports on a study of identifying and describing Lactobacillus plantarum strains from white brined Bulgarian home-made cheeses. It evaluates the antimicrobial activity, antibiotic susceptibility, and transit tolerance of the Lactobacillus plantarum strains. It demonstrates that Gram-negative bacteria including human pathogens are independent on organic acids or hydrogen peroxide. It shows that all lactobacillus strains were responsive to amoxicillin and sulfamethoxazole/trimethoprim and resisted lactame antibiotics, nalidixic acid, ciprofloxacin, streptomycin, and vancomycin. It also manifests that the strains' tolerance to low pH, bile salts, pepsin, and pancreatin which were the same in the gastrointestinal tract was strain-dependent.