Identification And Biological Activity Evaluation Of Three Microbial Strains Isolated From Deep-sea Sediments

Deep-sea sediments cover more than 50% of the Earth's surface. Deep-sea microorganisms live in the high-pressure, low temperature (some regions in high-temperature such as hydrothermal mouth), anaerobic, extreme pH, high salt concentration, high metal concentrations, no light, oligotrophic, high-halogen and other special extreme enviroment. Because of its particularity of the ecological environment, deep-sea microbes have some specific metabolic pathways and genetic background; their secondary metabolites have peculiar, novel chemical structures, and diverse characteristics.In our study, 31 deep sea sedimental samples collected by the 20th voyage of Chinese Ocean No.1 ship were used to isolate and identify selectively actinomycetes and fungus originated from deep sea, in addition, anti-tumor and anti-pathogenic activity detection were then carried on. 4 strains of bacterias of actinomycetes and 19 strains of fungus have been obtained, in which there were one novel strain---a bacteria of actinomycete YLB-01~T, two potential novel fungi Eu4 and Eu17, respectively.Modern Polyphasic taxonomy research methods were used to identify the novel strain YLB-01~T from morphological, physiological, biochemical characteristics and molecular classification. The strain YLB-01~T was named Microbacterium sediminis sp.nov. Through morphological and phylogenetic analysis, Eu4 was indentified as Ascomycetes Eurotiales Trichocomaceae Emericellopsis sp., with optimal growth at 28℃on PDA, and tolerant under high pressure 80MPa; while, Eu17 was indetified as Ascomycetes Hypocreales Tuberculariaceae Fusarium sp., with optimal growth at 20℃on YM, and had poor pressure tolerant under 40MPa. The isolate showed less than 98% ITS gene sequence similarity with respect to all of the published species. Eu4 and Eu17 were potential novel species, and need further analysis on physiological and biochemical characteristics analyses were needed to identify.The ethyl acetate extracts from the supernatant of fermented media of the 3 strains were used to test the antitumor and antibacterial activities. The result showed that, the extracts of YLB-01~T had antitumor and anti-pathogenic activity weakly, the extracts of Eu4 had anti-pathogenic activity and no antitumor activity, the extracts of Eu17 had antitumor and anti-pathogenic activity strongly.