Screening On Anti-allergy And Characteristic Study Of Lactobacillus Rhamnosus

We isolated 8 strains of Lactobacillus rhamnosus which has strong acid and bile salt tolerance ability from baby stool,and it was identified as W110,W119,W120,W123,W124,W126,W127 and L22B through morphologic observation,physiological and biochemical tests as well as 16S rRNA sequence analysis.The acid and bile salt tolerance ability and probiotic properties of 8 strains of Lactobacillus rhamnosus were studied further.The results showed that the distribution of 8 strains of Lactobacillus rhamnosus were regulation,begin to enter logarithmic phase in 3-4 hour and stationary phase in 22 hours.Crude polysaccharide yields of 7 strains of Lactobacillus rhamnosus exceed 1 00?g/mL on 12hours in logarithmic phase except Lactobacillus rhamnosus W123.The milk can be curded between 24hours with pH 3.82±0.04,3.71±0.06 and titration acidity at 50.73±1.86,46.5±3.00 by Lactobacillus rhamnosus W120,L22B.The result of the viable count exceed 108 CFU/mL though the viable count of Lactobacillus rhamnosus W110,W119,W123,W124,W126 and W127 reduced one order of magnitude under the condition of pH 2.5 and maintained for 2 h in MRS fluid medium while Lactobacillus rhamnosus W120 and L22B reduced two order of magnitude;meanwhile the result of the viable count exceed 108CFU/mL though the viable count of Lactobacillus rhamnosus W110,W119,W124,W126 and W127 reduced one order of magnitude under the condition of 0.3%bile salt maintained for 2h in MRS fluid medium while Lactobacillus rhamnosus W120,W123 and L22B reduced two order of magnitude.The results showed that it was almost as L.rhamonsus GG according to these result,even more this ability provide advantage for intestinal colonization and subsistence of Lactobacillus rhamnosus.In addition,the ability of anti-allergy of 8 strains of Lactobacillus rhamnosus was study preliminarily by a screen model of in vitro anti allergic activity by method of Elson-Morgan and cell experiment.The result showed that Lactobacillus rhamnosus W110,W120 and W124 can be used in cell experiment because of the stronger inhibition ratio(IR)on hyaluronidase by the method of Elson-Morgan.The results of Lactobacillus rhamnosus W120 have the highest antiallergic activity by cell experiment in accordance with the result of the screen model of in vitro antiallergic activity.These results indicated that 8 strains of Lactobacillus rhamnosus we isolated have potential application value on development of fermented food and probiotic drink.