[Phylogeny analysis and identification of two bacterial strains sourcing from human intestine and having resistance to acid and bile].

OBJECTIVE

To screen bacteria for the engineering bacteria expressing and secreting high activity beta-galactosidase, and two bacterial strains called as R92-2 and R111 with acid and bile resistances would be isolated from health human intestine to strain identification and phylogenetic analysis.

METHODS

These two strains were first been identified with phenotype characteristic analysis. Then the 16S rDNAs of these two bacterial strains were amplified and sequenced with the primers designed by the conserve sequences. DNA sequences were blasted against GenBank, and the phylogenetic trees were constructed.

RESULTS

Phenotype characteristic analysis showed that both of the bacterial strains belonged to lactic acid bacteria. Results of Blastn showed that 16S rDNAs of R92-2 and Weissella cibaria had 100% homology; 16S rDNAs of R111 and Enterococcus faecium had 100% homology too.

CONCLUSION

R92-2 belongs to Weissella cibaria strain; R111 belongs to Enterococcus faecium strain. These two stains may be used to construct the engineering bacteria expressing and secreting high activity beta-galactosidase.