The interaction between nine lactic acid bacteria (LAB) and five yeast strains isolated from airag of Inner Mongolia Autonomic Region, China was investigated. Three representative LAB and two yeasts showed symbioses were selected and incubated in 10% (w/v) reconstituted skim milk as single and mixed cultures to measure viable count, titratable acidity, ethanol and sugar content every 24 h for 1 week. LAB and yeasts showed high viable counts in the mixed cultures compared to the single cultures. Titratable acidity of the mixed cultures was obviously enhanced compared with that of the single cultures, except for the combinations of Lactobacillus reuteri 940B3 with Saccharomyces cerevisiae 4C and Lactobacillus helveticus 130B4 with Candida kefyr 2Y305. C. kefyr 2Y305 produced large amounts of ethanol (maximum 1.35 g/L), whereas non-lactose-fermenting S. cerevisiae 4C produced large amounts of ethanol only in the mixed cultures. Total glucose and galactose content increased while lactose content decreased in the single cultures of Leuconostoc mesenteroides 6B2081 and Lb. helveticus 130B4. However, both glucose and galactose were completely consumed and lactose was markedly reduced in the mixed cultures with yeasts. The result suggests that yeasts utilize glucose and galactose produced by LAB lactase to promote cell growth.

Probiotics exert additional favorable effects on gut microbiota, making them excellent potential complements to cholesterol-lowering drugs like ATO.

No abstract

Lactobacillus plantarum was not only one of the most popular probiotics, 2 but also one of the most versatile lactic acid bacteria. L. plantarum LLY-606 and L. 3 plantarum pc-26 are strains isolated from human gut that are intended to be explored 4 as probiotics. In this study, the genome sequences of LLY-606 and pc-26 were 5 sequenced, and multiple genes related to probiotic properties were analyzed. First, the 6 pathogenicity of these strains was evaluated, and antibiotic resistance genes were 7 surveyed at the whole genome level to determine their primary safety. And then, genes 8 for stress response, plantaricin (pln) biosynthesis, extracellular polysaccharide (EPS) 9 biosynthesis, and bile salt hydrolase (BSH) were analyzed to evaluate their industrial 10 utilization, adhesive capacity, and survival ability in gut, which were properties 11 fundamental for probiotic strains. The physiological features assured by these genes 12were assayed in vitro. The strains were then evaluated in vivo for their ability to lower 13 cholesterol, and they were both found to be effective in improving 14 hypercholesterolemia in golden hamsters. In this study, a genetic pre-evaluation was 15 conducted through genome analysis combined with in vitro physiological assay, and 16 the probiotic properties of these strains were verified in vivo. 17