[Biodiversity of culturable halotolerant and halophilic bacteria isolated from saline-alkaline soils in Songnen Plain].

OBJECTIVE

To analyze the biodiversity of halotolerant and halophilic bacteria the bacteria in saline-alkaline soils in Songnen Plain, we isolated and purified bacteria samples in the area.

METHODS

Halotolerant and halophilic bacteria were isolated from the enriched cultures of the saline-alkline soil samples through the traditional culture method, and 16S rRNA sequences were amplified and analyzed for the determination of phylogenetic relationships.

RESULTS

Forty strains were obtained and classified into 34 species, 16 genera, 8 families, 3 phylum (Firmicutes, gamma-Proteobacteria and Actinobacteria) in the Domain Bacteria. The genus Staphylococcus is the predominant group, followed by Halomonas, Oceanbacillus, Bacillus, Kocuria and Pseudomonas. The 16S rRNA sequences of 9 strains showed 97.2 to 99.0% similarities with their closest type strains, suggesting that they may be the potential novel species. The salt tolerance of the strains is mainly concentrated on the 5% - 10% NaCl while alkaline pH resistance of the strains is between pH 9 and 12. Based on the NaCl dependence, 62.5% of the strains were grouped into the halotolerant bacteria, and the rest into the moderate halophiles.

CONCLUSION

The halotolerant and halophilic bacteria are very rich in the saline-alkaline soils in Songnen Plain, and the genera Staphylococcus and Halomonas are the predominant groups. Almost all the bacteria from this area could tolerate not only at the high concentration of NaCl, but also at high alkaline pH. More importantly, a number of novel species may be included in this area.