Studies On Extraction And Antibacterial Biochemical Characterization Of Lactic Acid Bacteria In The Koumiss

In this study, the antibacterial characterization of forty-seven strains of lactic acid bacteria which isolated from ten samples of koumiss collected from the heardsman's home in Inner Mongolia-XiLinGuoLe region were studied.The total of forty-seven strains of lactic acid bacteria were not screened for antagonistic activities to Staphylococcus aureus and Escherichia coli.The bodies of only ten Lactobacilli were shown to inhibit the growth of indicator organism-Listeria monocytogenes or Bacillus subtilis among twenty-six Lactobacilli.Nine Lactocilli also exhibited inhibitory activity against indicator organism.Among them there are seven strains which not only the supernatants but also the bodies exhibited inhibitory activity against indicator organism- Listeria monocytogenes or Bacillus subtilis and six of seven Lactocilli were Enterococcus faecalis.Two of the seven Lactocilli,3-3-2 and 4-3-2,which have higher inhibitory activity were chosen for further study.There was a rapid increase of bacteriocin activity after the start of the exponential phase.The maximal level did not decline over thirty hours coinciding with the low pH reached at the time.The antibacterial substances extracted from cell culture liquor were proteins,which activity spectrums was narrow.The activity were not changed more under a wide pH range,but appeared to be heat labile.Some surfactants had no effect on the inhibitory activity. The antibacterial substances of 3-3-2 did not sensitivity to the proteolytic and a -amylase.