Screening Of Lactobacillus For Vitamin B₁₂-producing And Studies On Biological Characteristics

16 Lactobacillus were studied in this subject,Screening the one can product vitamin B12 and analyzed vitamin B12-producing ability in difference condition.Stud- ied on temperature,bile-tolerance and acid-tolerance of Lactobacillus for vitamin B12-producing.The result show that the eight of sixteen Lactobacillus could product vitamin B12,SE7-1,SE5-1 and SE1-3 had higher quantity of the Vitamin B12 than others.According to their physiological and biochemical properities,SE7-1 was identified to Lactobacillus casei subsp.Rhamnosus , SE5-1 was Lactobacillus. acidopHilus, SE1-3 was Enterococcus faecalis, These 3 strains were evaluated to determine the bile-tolerance and low pH on the ability. At pH 2.0 in culture media the number of the 3 strains were reduced, and these 3 strains could grow well in pH 5.0 MRS culture media .Bile-tolerance concentration of the 3 strains were 0.3%.The SE7-1 demonstrated higher ability of bile-tolerance than others . And SE5-1 demonstrated higher ability of bile-tolerance than SE1-3.At the same time,The vitamin B12-producing ability of these 3 strains were influenced by pH value,Temperature , Time and Volume of bacteria.The result show that influence was difference from strain to strain.Influence of SE7-1 was pHï¹¥Temperatureï¹¥Timeï¹¥Volume of bacteria, The highest quantity of vitamin B12-producing was 90.9862mg/L .Influence of SE5-1 was pHï¹¥Volume of bacteriaï¹¥Temperatureï¹¥Time, The highest quantity of vitamin B12-producing was 28.5246mg/L.SE1-3 was pHï¹¥Temperatureï¹¥Timeï¹¥Volume of bacteria, The highest quantity of vitamin B12-producing was 58.4528mg/L.