Microbes isolated from Saline-Alkali Soil of Northern Ningxia ： insight on microbial diversity and antibacterial activity

Microbial secondary metabolites are important sources of drug lead compounds. However, due to the discovery of novel microbial resources and the blindness of traditional screening strategies, the number of drugs developed from traditional microorganisms is decreasing year by year. Microorganisms in special habitats have attracted more and more attention because of their unique growth and evolution conditions and stress-resistant genes, which can produce molecules with novel structures and unique pharmacological activities. In order to explore the diversity of microbial resources, 104 strains with certain morphological characteristics were isolated from special habitat saline-alkali soil in northern of Ningxia. The ITS and 16S rRNA sequences of those strains were sequenced and identified by genome extraction technology. Among them, 38 strains of fungi and 44 strains of bacteria were identified, including 36 strains of Streptomyces , 5 strains of Amycolatopsis , 1 strain of Cellulomonas , 1 strain of Bacillus and 1 strain of Aurysmus . Furthermore, the antibacterial activity of 44 strains of bacteria were studied. 36 strains of Actinomycetes with antibacterial activity were screened out, including 5 strains of Amycolatopsis and 31 strains of Streptomyces , with active strains accounting for 81.81%. Among the active strains, the secondary metabolites of 35 strains had significant antibacterial activity against Proteus vulgaris , 20 strains had obvious inhibitory activity against Staphylococcus aureus , and 14 strains had certain growth inhibitory activity against Candida albicans . The results showed that most of the microbial strains isolated from saline-alkali soil in northern Ningxia had strong antibacterial activity, and possess the potential for further exploring antibacterial active secondary metabolites. This study not only enriched the microbial resources in special habitats, but also laid a foundation for further isolation of antibacterial lead compounds from saline-alkali soil.