Microbial Diversity And Fermentation Identification Of Active Substances In Indian Ocean Sediments

The development and utilization of various resources are indispensable to the accelerated development of economic activities of human society and the industrial process with rapid development momentum.Today,when the resources of land are gradually exhausted,people turn their eyes to the ocean.Deep sea is one of the important strategic resources which has not been fully recognized and exploited by human beings.The deep sea area is characterized by perennial darkness,high salinity,high pressure,and wide range of water temperature(deepsea hydrothermal and submarine cold springs),which generates a variety of marine microorganisms.Marine microorganisms live in such a complex marine environment,so the metabolites are also of great research value.Samples in this study were collected from sulfide and sediments in the southwest Indian Ocean by Jiaolong.Bioinformatics method was used to analyze the sediment samples to explore the microbial diversity and to predict the 16 S function.After the four samples were cultured,separated and purified,the strain resources were obtained.Strains with good inhibitory effect on the growth and production of Aspergillus parasiticus were screened by plate confrontation,tip-culture and other experimental methods.The isolated strains were identified,and the strains with good inhibitory effect were fermented to extract active metabolites and verify their antibacterial effect.The main conclusions are as follows: Culture-free diversity analysis of deepsea sediment samples was conducted.JS5 samples had the highest OTU abundance and the richest species composition.JS6 samples had the lowest OTU abundance and the lowest species composition richness.Compared with the three samples,the species are quite different.The dominant species in JS1 is OTU2670(uncultured Bacteroidales F082),while the dominant species in JS5 is OTU99(Marinobacter?vinifirmus),The dominant species of JS6 was OTU 1554(Sulfitobacter sp.).The bacterial AS-11 was screened by plate test on deep sea sediment samples,which had good inhibition effect on the growth of Aspergillus parasitica NFRI 95.The inhibition effect of AS-11 was up to 100 %,and the fermentation product had high temperature stability.Through uniform design,the optimal fermentation conditions of AS-11 strain were determined AS follows: seawater content of 20 %,p H of 6,3.5 g/L yeast extract,8 g/L glucose,inoculation amount of 2 %,culture at 20 ?,150 rpm for 3 days.The results of UPLC-MS analysis showed that there were Cyclo(L-leucyl-Lprolyl)and Indole in AS-11 fermentation broth,which could inhibit the growth and toxicity of Aspergillus parasiticus Speare NFRI 95.