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Lactobacillus ubiquitous in nature, is an important human and animal physiology bacteria. So it's flora species and quantities directly affect human health. Study found that probiotic bacteria have a good effect, regulation of intestinal metabolism, improve the internal environment pH, due to many different types of lactic acid bacteria, different strains of functions and mechanism needs further study. This issue through in vivo and in vitro tests, including the separation and identification of lactic acid bacteria, physiological characteristics, biological antagonism against pathogens, in vitro and in vivo studies of cholesterol-lowering, the system explains the separation of the functions of lactic acid bacteria and possible mechanism of action. Test uses MRS solid medium, respectively, from the natural fermentation of fresh sauerkraut juice and yogurt commercially isolated 20 Gram-positive lactic acid bacteria, initially identified as lactic acid bacteria. Screened according to the amount of acid produced six high-yielding strains of lactic acid and a series of physiological and morphological characteristics, biochemical identification, determination were plantarum, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus brevis. Strains of acid, salt test results show that the six lactic acid bacteria and acid, salt properties. 6 bacteria are slow growing, the growth cycle is longer. In which the growth rate of strain S2 than the other five lactic acid bacteria to be fast, and the lag is short. The growth rate of other strains are relatively slow, and long lag phase, OD values ??less stable. Acid, salt resistance test showed that lactic acid bacteria strains of the six initial pH value of the medium at 6 to 7, the number of viable cells decreased with the increase of concentration. Antibacterial test results by the lactic acid bacteria, that the separation of lactic acid bacteria E. coli, P. aeruginosa, Staphylococcus aureus bacteria have indicated significant inhibitory effect, combined with the acid production of each strain can be seen, production The higher the amount of acid strains, antibacterial effects are the best. Application of MRS medium containing cholesterol respectively, from sauerkraut, yogurt lactic acid bacteria in vitro extract cholesterol screening highest strains in animal experiments. Study found that two lactic acid bacteria have lipid-lowering effect, in which the effect of mixed fermentation strains of bacteria is superior to plant. Based on the above test results, can be found isolated from naturally fermented sauerkraut juice and commercially available lactic acid bacteria in yogurt have good biological antagonism and cholesterol-lowering effects, there is great potential for development and application.
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