Identified And Phylogenetic Studies Of Lactic Acid Bacteria Isolated From Raw Milk Of Yili Area In Xinjiang

Objective: Animal raw milk and various dairy products have became favorite nutritious food for human in thousands of years as well as provided the ideal habitat for different exogenous microbes,which formed a complex microbial groups(microbiota).microorganisms in raw milk are not only play an important role on processing of dairy products quality,but also closely related to the health of consumers.Wild lactic acid bacteria in raw milk are mainly from the forage of farmed animal habitats,feed and feces.Relatived to the dairy fermentation strains which have been developed for the commercialization,the physiological characteristics of wild LAB are more complicated and varied.It is pivotal for the formation of the characteristics of dairy products.Thus understanding the composition of microorganisms in raw milk is very important.Method :The original milk in this research are from six areas of YiLi in xinjiang.We extracted the suspected LAB from raw milk using MRS,M17 and ball medium.The traditional physiological and biochemical,primer amplification,repetitive genomic fingerprinting(rep PCR)fingerprint and 16 s rRNA gene sequence analysis method were adopted to study the genetic diversity of the original milk in lactic acid bacteria.Conclusion:1.The number of lactic acid bacteria in raw milk is 7.5-8.2×105 CFU ml-1.Sixty-nine LAB were extracted from the raw milk using MRS,M17 and ball medium.Results have been purified from MRS culture medium,52 strains colony morphology for white.light yellow strains have 4 strains.gray have 7 strains.The remaining 6 strains were ivory.Most strains(62 strains)colony form smaller volume,about 1 mm below,the remaining 7 strains of bacteria were about 1 ~ 2 mm.2.Using Lactococcus ? Lactobacillus and Enterococcus genera primers for PCR amplification,banding results showed that 13 isolates belong to Lactococcus,PCR products of about 700 bp;Results 20 strains belongs to Enterococcus,and PCR products of 112 bp;Gram's staining of rods with Lactobacillus SPP.,primer amplification,purpose stripe in about 250 bp.So the 7 strains as Lactobacillus.3.The calculation intergeneric PCR,rep PCR fingerprint and 16 S rRNA gene sequence analysis of 69 strains isolated strains identification to species level.16 S rRNA gene sequence alignment results show that the sequencing strain and database known strains similarity were greater than 98%.All strains belong to 6genera of 10 species and subspecies,respectively is: Lactococcus(19%),Lactobacillus(10.1%),Leuconostoc(27.5%),Pediococcus(7.2%),Streptococcus(7.2%)and Enterococcus(29%).Enterococcus faecium(20 strains)accounted for 28.9% of isolates is the dominant species in Yili region of the original milk,Followed by Leuconostoc lactis and Lactococcus lactis,accounting for 20.2% of the total isolates and20.2% respectively.In addition,there are bound to the small number of 7 strains of strains of Streptococcus respectively equinus,Pediococcus pentosaceus,Lactobacillus pentosus,Lactobacillus reuteri and Leuconostoc garlicum,Leuconostoc citreum and Leuconostoc mesenteroides.Lactic acid bacteria distribution differences among different samples,among which a total of 14 strains of lactic acid bacteria was isolated ZS19,including 1 Streptococcus,five Enterococcus,2 Lactococcus and Lactobacillus and 5Leuconostoc.ZS22 number four genera of lactic acid bacteria was isolated,respectively is: Streptococcus(3),Enterococcus(1),Lactococcus(3)and Lactobacillus(1).TKS57 most abundant diversity of lactic acid bacteria,a total of five genera(Streptococcus,Enterococcus,Lactococcus,Pediococcus and Leuconostoc).ZS25 samples containing four genera,Lactobacillus advantage bacterium group,for this sample and sample number ZS30 advantage is for Leuconostoc(8).In addition to ZS26 samples contain only Enterococcus(9),the kinds of lactic acid bacteria is more for most of the samples.It is worth noting that theEnterococcus and Lactococcus were detected in the five samples.Thirty-five strains after 16 S rRNA gene sequencing result has been uploaded to the GenBank database.the serial number were KX583568 ~KX583575,KX583577 ~ KX583580.The results show that Yili region rich in resources,lactic acid bacteria species in the original milk is various,which has great development value.