Determination of some functional properties of lactic acid bacteria and yeasts isolated from traditional kefir grains

In this study, Lactic Acid Bacteria (LAB) and yeast species were isolated and identified from Kefir grains following the activation of the kefir grains collected from different regions of Turkey (İstanbul, İzmir, Bursa, Erzurum, Erzincan) and the functional characteristics of kefir isolate LAB species were determined. For the discrimation of LAB and yeast isolates RAPD-PCR analysis was applied followed by the genotypic identification of the distinct isolates and in this study Lactobacillus kefiri, Lactobacillus kefiranofaciens subsp, kefirgranum, Lactobacillus diolivorans, Lactobacillus kefiranofaciens, Lactobacillus otakiensis, Lactococcus lactis subsp. cremoris, Lactococcus lactis, Lactococcus lactis subsp. hordniae, Acetobacter fabarum, Enterococcus durans, Acetobacter okinawensis, Lactobacillus paracasei subsp. tolerans, Lactobacillus paracasei and Acetobacter orientalis were isolated as bacterial species and Pichia kudriavzevii, Kazachstania unispora, Saccharomyces cerevisiae ve Kluyveromyces marxianus were the yeast isolates. The functional characteristics of LAB species in terms of antifungal and antibacterial activity, antibiotic resistances and the level of exopolysaccharide (EPS) production and the EPS production characteristics were determined. Important levels of antibacterial and antifungal activities were observed in kefir isolates (L. diolivorans, L. lactis, L. kefiranofaciens, L. otakiensis, L. paracasei, L.kefiri) and these functions were altered depending on strain specific conditions. All LAB species tested produced a heteropolymeric EPS containing glucose and galactose and some strains produced a fructan type EPS. The level of EPS production among the kefir isolates were observed to be similar (p>0.05). In conclusion, this study revealed the rich microflora of kefir grains and the functional characteristics of the isolates in which theri presence results in the functional roles of kefir.