Probiotic importance of conjugated linoleic acid production from different strains of Lactobacillus, Propionibacterium and Bifidobacterium genus

In this study, 32 propionibacteria were isolated from 78 hand-made cheeses obtained from different regions of Turkey having a porous structure. Classical and molecular identification results of the isolates demonstrate that the most dominant propionibacteria species in the cheese was Propionibacterium freudenreichii (88%); in addition P. acidipropionici, P. jensenii and P. thoenii species were also present. Conjugated linoleic acid (CLA) synthesis capabilities of the isolated propionibacteria and lactobacilli and bifidibacteria selected from the culture collection of Gazi University Biotechnology Laboratory were scanned. All strains were determined to synthesis CLA and synthesized more CLA from linoleic acid (LA) than sunflower seed oil. The highest CLA synthesis was observed in the B. breve A28 strain in LA 30% and sunflower oil 14%. Among propionibacteria, the P. freudenreichii spp. shermanii S28 (28% in LA, 12% in sunflower oil) and P. thoenii S72 strains stand out. The ideal temperature, pH, LA concentrations and incubation period for CLA synthesis were determined and the studies were conducted under these conditions. A total of 72 hours incubation at pH 6.8, 30oC, 100 µg/ml LA concentration was determined to be ideal in propionibacteria, and 48 hours incubation at pH 6.8, 37oC, 100 µg/ml LA concentration was determined to be ideal in bifidobacteria. Aim of this study, CLA synthesis of the highly capable strains under optimal conditions and the cholesterol lowering, anti-oxidant, adherence to human intestine epithelium cell lines and anti-carcinogenic activity of this CLA were examined, and discovering new probiotic strains that can be used in the fields of food and health was targeted. The highest cholesterol relief was 33% in P. freudenreichii ssp. shermanii S28 strain having high CLA synthesis, and this value was found to be 47% when CLA synthesis is present. While this increase in ratio was approximately 14%, it was observed to be 3-6% in strains that synthesize CLA to a lower extent. The strains were found to possess antioxidant effect. It was determined that anti-oxidant effect increased in various proportions with CLA synthesis and the highest increase in iron chelating activity was found to be in the P. thoenii S72 strain (from 26% to 45%). The strains were determined to have the ability to adhere to Caco-2 and CCL-221 cell lines. The highest adherence in Caco-2 cell line of 58% was found to be in B. breve A28 and was 65% when CLA synthesis was present. While the strains demonstrated anti-carcinogenic effect on two cell lines in relation to adherence capability, the highest anti-carcinogenic effect was seen in Caco-2 cell line. While CLA synthesis increased the lethal effect of the strains on the cancer cell lines, approximately 8-25%, it was found not to be lethal in healthy fibroblast cell line and it even decreased the lethal effect of the strains to 3-4% from 9-14%. The results of the study show that S28, S72 and A28 strains were highly capable in CLA synthesis and associated anti-oxidant, anti-carcinogenic, cholesterol relief, and adhesion studies.Key words : Conjugated linoleic acid (CLA), Probiotic, Antioxidant, Anticancerogen, Cholesterol,