Research On Diversity And Biological Activity Of The Cultural Fungi In South Atlantic Deep-sea Sediments

With the increasingly advancement of technology and better understanding of the earth, researchers turn their eyes from the land to the ocean. Biological resources are excavated, especially the deep sea with peculiar ecological environment. Fungi, an important member of the deep-sea microbial family, has become the emerging resourcein marine organism exploration. Compared with terrestrial breeds, complex deep-sea environment breeds more diverse fungi, meanwhile whose metabolites’ bioactivity has also became one of the current research hotspots.In this study, 29 strains of fungi which were sampled in 15 deep sea sediments from the South Atlantic had been separated and cultured by plate method. Followed with bioassay by using ITS r DNA gene sequence analysis method, they belonged to four genera, which were Cladosporium, Aspergillus, Alternaria and Penicillium respectively. As to the rich diversity of species, Penicillium had been identified as dominant genus.By using oxford cup method, Tip-culture method, and MTT method, the anti-bacterial, anti-yeast, anti fungal activity and cytotoxic activity per strain had been tested, and the results were indicated as follows:For strain supernatant fermented by sea water PDA, there were 6, 3, 2, 1, 1 strains fungi fermented supernatant had anti-bacterial effect which could inhibite Saccharomyces cerevisiae, Enterobacter aerogenes, Bacillus Subtilis, Escherichia coli, Staphylococcus aureus respectively. 8, 14 strains fungi fermented supernatant had been showed to inhibite Aspergillus parasiticus mutant NFRI-95, and its toxin separately, for which including 4 strains completely suppress NFRI-95, 8 strains completely suppress aflatoxin. Pathogenic Fungi Fusarium of wheat had been restrained by 10 strains fungi fermented supernatant, including 1 strain absolutely restraint. There were 8, 2 strains mycelium extracts of organic reagents had anti-bacterial effect which could inhibite Bacillus Subtilis, Enterobacter aerogenes respectively. 3, 17 strains mycelium extracts of organic reagents had been showed to inhibite Aspergillus parasiticus mutant NFRI-95 with its toxin, and only inhibited its toxin separately, Pathogenic Fungi Fusarium of wheat had been restrained by 5 strains mycelium extracts of organic reagents.On the other hand, for strain supernatant fermented by fresh water PDA, there were 3, 1 strain fungi fermented supernatant had anti-bacterial effect which could inhibite Enterobacter aerogenes, Bacillus Subtilis respectively. 8, 15 strains fungi fermented supernatant had been showed to inhibite Aspergillus parasiticus mutant NFRI-95, and its toxin separately, including 1 strains completely suppress NFRI-95, 5 strains completely suppress aflatoxin. Pathogenic Fungi Fusarium of wheat had been restrained by 15 strains fungi fermented supernatant, including 1 stra in absolutely restraint. There were 1, 2 strains mycelium extracts of organic reagents had anti-bacterial effect which could inhibite Bacillus Subtilis, Enterobacter aerogenes respectively. 1, 6 strains mycelium extracts of organic reagents had been showed to inhibite Aspergillus parasiticus mutant NFRI-95 with its toxin, and only inhibited its toxin separately.A special strain which named MIE14 had been identified as having cytotoxic activity on Hela cell, no cytotoxic activity on human normal cells.Finally, highly active strains 13-3T and MHE23 had been applied to the optimization of fermentation by homogeneous design, in order to give full play to their antibacterial activity. Results indicated that, starch A medium was proven to be the optimum fermentation medium for strain 13-3T, and starch B medium was confirmed to be the optimum fermentation medium for strain MHE2 3, and their preliminary optimization of fermentation conditions were confirmed as culture temperature 21 ℃, culture time 4.12-6.57 d, inoculation quantity 7.05-8.61%, seawater quantity 50.89-100%, p H 7.7-8.2 for 13-3T, and culture temperature 21℃, culture time 10.83 d, inoculation quantity 5.35%, seawater quantity 9.87%, p H 8.2 for MHE23 respectively.