ИСЭГ ЦАГААН ИДЭЭНЭЭС ЯЛГАСАН СҮҮН ХҮЧЛИЙН БАКТЕРИЙН ШИНЖ ЧАНАРЫН СУДАЛГАА

Abstract

We isolated lactic acid bacteria from fermented dairy products, fermented mare’s milk and cow yogurt, which are traditionally produced by Mongolian herders, and carried out in vitro study of their probiotic properties. Culture 44c is 100% identical to species Lactobacillus helveticus (Lhelveticus) or a strain KT368987, isolated from Mongolian airag, while culture 65b is 99% identical to Lactobacillus delbreuckii subsp. bulgaricus (L.bulgaricus) or strain CP016393 isolated from camel fermented milk in Gobi-Altai aimag and characteristics of both cultures were the best among all cultures obtained in the present study. Isolated lactic acid rods completely inhibited the growth of gastro-intestinal pathogens which spread among livestock (E.coli 09, E.coli 026, S.abortusovis 0068) and Mongolian population (S.aureus 5695, S.aureus 5068, S.aureus SA27, E.coli 10963, E.coli 10977). As well as, we determined the properties, including resistance to the acidic environment of digestive tract and activity when using with common antibiotics, which are the basic requirements for bacterial strains used in functional food production. According to the result, when pH of the environment reached 3.5 or 4.0, growth rate of the strains was over 80 percent and the lactic acid strains were variably resistant to 10 antibiotics of 5 classes (penicillin, aminoglycoside, cephalosporin and macrolide). For example; Formation of 8.9±0.87 mm zone around all antibiotic discs for culture 44c of L.helveticus demonstrates the culture can be used in combination with these antibiotics for therapeutic purposes. Besides of these characteristics, CFU per ml was determined by growing on MRS nutrient medium under anaerobic condition. Moreover, CFU/ml was determined because its spectrum of activity depends on the number of bacteria per 1ml. L.helveticus 44c reached its highest volume (2503х1010) at 48th hour of growth, while L.bulgaricus 65b reached its highest volume (2503х1010) at 72th hour of growth. After they reached their highest volume, both of them tended to decrease. For this reason, these strains, especially L.helveticus 44c and L.bulgaricus 65b strains, are possible to be used as a source material for probiotics or functional food products.

Keywords

• Lactic acid bacteria, probiotic, antagonist activity, L. helveticus, L. delbrueckiis ssp.bulgaricus