The Medium Optimization And Microcapsule Preparation Of Bifidobacterium With Cholesterol-reducing Ability From Guizhou Xiang Pigs

With rising living conditions,the incidence of cardiovascular disease is becoming higher and higher.The main reason is that ingesting high cholesterol will lead the serum cholesterol levels to rise.A large number studies from the world have shown that bifidobacterium is a kind of probiotic which has good ability of reducing cholesterol.In this study,we select the intestinal soluble content and faeces of Guizhou Xiang pigs from special resource of Gui Zhou province as the screening source.A strain of bifidobacterium with high cholesterol-reducing ability and with good acid-resisting and bile salt-resisting ability was obtained by screening.Then the optimum medium composition was found by optimizing the medium composition.At last,the bifidobacterium microcapsule was prepared by embedding the bifidobacterium with sodium alginate materials.There are the following main conclusions:1.In this work,the Xiang pigs from the special resource of Guizhou province was used as the screening resource.We screened primarily by the MRS culture medium with Mupirocin lithium salt and PTYG agar plate medium with X-gal.70 strains bifidobacteria were obtained by combining the specific colonial morphology and morphology of bifidobacteria strains.2.With the cholesterol removal rate as the target,the cholesterol-reducing ability of the 70 strains from preliminary screening experiment were tested by OPA.And then the acid-resisting and bile salt-resisting ability of the bifidobacterium with high cholesterol-reducing ability were tested by simulating gastrointestinal tract environment of human.At last,a strain bifidobacterium BZ11 which has the high cholesterol-reducing ability and with high acid-resisting and bile salt-resisting ability was obtained.The cholesterol removal rate had reached 38.52%.It was identified asbifidobacteria animalis subsp. Lactis by analyzing the strain morphological and 16 S rRNA sequence analysis.3.The medium components of the bifidobacteria animalis subsp. lactis BZ11(CGMCC NO.10224)which we obtained was optimized.On the base of single factor experiment,three key factors were obtained by designing PB experiment to study seven kinds of medium components.And then we confirmed the optimum concentration of these key factors for improving the bifidobacterium growth mass by Steepest Ascent Design and Box-Behnken Response surface optimization design.The results showed that the optimum medium components are 1.08%maltose,0.89%glucose,0.51% tryptone,0.89% soya peptone,0.89% yeast extract,14.33% carrot juice and 17.78% cabbage juice.The maximum light absorption value of bifidobacterium growth mass in OD600 is 1.714 and the viable count reaches 1011 order of magnitudes.The viable count had been increased an order of magnitude and the cholesterol-reducing ability had been increased up 8.26% than before optimizing.4.The bifidobacterium microcapsule was prepared by embedding the bifidobacteria animalis subsp. lactis BZ11( CGMCC NO.10224) with sodium alginatel materials.The microcapsule with high acid-resisting and bile salt-resisting ability were obtained by Artificial simulated gastric juice,Artificial simulation intestinal juice and Artificial simulated conditions of the gastrointestinal tract experiments and so on.The study showed that the embedding rate had reached 87.89%and the enteric release rate reached 90.8%.