Screening And Fermentation Of Probiotics From Human Milk

Probiotics refer to the living bacteria with probiotic function to the host after proper dosage intake.Human milk contains a large number of probiotics,and its diversity has been proved by domestic and foreign studies.Researchers screened out a variety of probiotics from healthy breast milk,such as lactic acid bacteria,bifidobacteria and so on.Probiotics in breast milk have the advantages of adapting to the low p H environment in the stomach and high bile salt environment in the intestine.However,different probiotics have different probiotics.Specific physiological and biochemical experiments are needed to determine the tolerance of probiotics in high acid and high bile salts.Only living bacteria entering the gastrointestinal tract can play a probiotic role.In this paper,18 probiotics were isolated from 50 human milk samples in Beijing and identified by 16S r DNA.Among them,12 strains were Lactobacillus plantarum,3 strains were Lactobacillus Grignard and 3 strains were Lactobacillus reuteri.The acid resistance,bile salt tolerance and adhesion properties of 18 selected probiotics were studied.It was found that the acid resistance,bile salt tolerance and adhesion properties of Lactobacillus reuteri B1-27 were the best.The growth characteristics,acid resistance,bile salt tolerance and fermentation characteristics of B1-27 were systematically studied.The results showed that Lactobacillus reuteri B1-27 had strong tolerance when cultured in p H 3.0 environment for 24 h and bile salt concentration of 4.5%for 6 h,and the number of viable bacteria was above 10~6 CFU/m L.The whole genome sequencing results showed that the genome size of Lactobacillus reuteri B1-27 was 2017551 b P,GC content of 39%,in line with the characteristics of Lactobacillus reuteri:GO,KEGG,COG,NR gene library for annotation,the results showed that Lactobacillus reuteri B1-27 contains genes involved in metabolism,translation,ribosome structure and biosynthesis,indicating that the strain has strong biosynthesis ability.The results showed that Lactobacillus reuteri B1-27 could be used in fermented milk.In conclusion,Lactobacillus reuteri B1-27 from human milk has excellent acid and bile salt resistance,strong adhesion,and can be fermented to produce fermented milk with good sensory evaluation.It can be used as a potential probiotic candidate strain,and can be used to develop new fermentation products and improve product quality.