Diversity of cultivable bacteria isolated from marine sediment environments in South China Sea

Abstract:

[Objective] Investigating the diversity of the cultivable bacteria in marine sediment environments. [Methods] Twenty sediment samples collected from South China Sea were used for bacterial diversity research by using the culture dependent method and 16S rRNA gene sequencing. [Results] Total of 200 strains were obtained, which belong to 47 genera and 99 species and spread in four phyla: Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes. The predominant group is phylum Firmicutes, in which genus Bacillus takes a great proportion of 55.6%. A few strains in phyla Actinobacteria and Bacteroidetes were also obtained. Eight potential new species and 3 potential new genera were discovered in phyla Firmicutes and Actinobacteria. [Conclusion] The preliminary study indicates that genus Bacillus is the dominant group in sediment environments of South China Sea and bacterial diversity showed a decreasing trend with the increase of sampling depth. Sampling depth maybe is one of the important factors to influence the distribution of bacteria. Diversity of bacteria and novel bio-resources in the sediment environments are very abundant and need to be further researched. Isolating methods and isolation media are the crucial factors to recover the microorganisms inhabiting the sediment environments.

Key words:South China Sea, Sediment environment, Bacteria, Cultivable diversity, Potential new species