Studies On Lactobacillus Acidophilus For Feed-Using And Enumeration Assay Of Lactic Acid Bacteria

Lactobacillus acidophilus is an important probiotic bacteria in the familly of Lactobacillus. Lactobacillus acidophilus has its important function on the people,s health ,and keeping animal gastro intestinal envitronment, so that it is a focus subject in the field of microbial research . In this subject,the biology characteristic of Lactobacillus acidophilus and the svmbiosis with Streptococcus lactis acidi were studied.The incubating conditions and character such as biomass , acid production,rejecting acid and salt were studied, As a result, the optimum growth temperature of Lactobacillus acidophilus was 360C to 380C and the initial pH was 5.5 to 6.2。The no shaking was better than shaking. The highest biomass would be up to 1010CFU/mL,and the highest acid degree would be 2190T。however Lactobacillus acidophilus had a stronger acid and salt resistance, and antagonistic activity on the Escherichia coli and salmonella sp。The present study showed that fructose had a significant effect on growth of Lactobacillus acidophilus .The incubation of MRS which has been added inulin promoted the counts of Lactobacillus acidophilus and the degrees of lactic acid .After 48h incubation at 37oC,the cell counts and lactic acid degrees of LA in test groups were higher up to 1010CFU/mL and 100T than that in contral groups。The antagonistic character of Lactobacillus acicdophilus growth out of the body were studied, The result should that the metabolite products of Lactobacillus acicdophilus had differential antagonistic activity on the Escherichia coli and salmonella sp. with changing of the time of inculation.But it did not keep back the Lactobacillus bacterium growth。The micro-ecological relationship between Streptococcus lactis acidi and Lactobacillus acidophilus were studied in way of co-cultivation in terms of acid production and bacterium fermental inhibition, The maximum inhibition against Staphylococcus aureus ATCC25923 was reached when co-cultivation were run at 33oC for 48 hours。The biomass and total organic acid production by were much higher than that of any one of their individual pure cultination, in which lactate reached 23.175mg/L at 24 hours, and acetate was kept at adout 12mg/L during the entire cultivation。The mixture inoculation ratio of Lactobacillus acidophilus and Streptococcus lactis acidi was ranked as 1:1, 2:1 and 1:2 on purpose of inhibition against bacteria. The results showed that their co-cultivation could increase organic acid production. The bacterium inhibition activity of fermentation liquid was strengthen. The Streptococcus lactis acidi and Lactobacillus acidophilus could live together in a harmony way in the mixed culture resulting from their good micro-ecological relationship。An assay of enumeration on Lactobacillus plantarum and Pediococcus pentosaceus was established from one product of silage inoculant bacteria. The reproductive ability and survivial ability of the latter were much higher than that of the former。An assay on enumeration of Streptococcus faecalis was established and its identification protocol was described。...