Diversity and antibacterial activity of culturable actinobacteria in karst cave soil in Xingyi, Guizhou

Abstract:

[Objective] To investigate the diversity of culturable actinobacteria of samples from karst cave in Xingyi county of Guizhou province and analyze their ability of production of secondary metabolites. [Methods] The spread plate method was used to obtain the diversity of culturable actinobacteria from different type karst cave samples (sediment and rock) with many kinds of media. Three ferments media were selected to detect the production of secondary metabolite compounds of these culturable actinobacteria. [Results] Through the comparative analysis based on 16S rRNA gene sequences similarities, we obtained a total of 251 isolates belonging to 44 genera, among of which the genera Streptomyces, Micromonospora, Rhodococcus, Microbacterium and Nocardia were the dominant actinobacterial group, and the proportion of them were 24.30%, 11.95%, 9.16%, 7.17% and 6.37%, respectively. During the analysis of production of bioactivity of secondary metabolite compounds, 35 isolates showed the bioactivity to the indicator pathogen bacteria, among of which were main from the genera Streptomyces and Micromonospora. [Conclusion] The results indicated that there were richness actinobacterial resources in the karst cave niche in southwest of Guizhou, and much more isolates had the ability to produce secondary metabolite compounds, which would become potential species for the pharmaceutical industry, and hence it had the most value for further exploration and research.