Research On Metabolites Of Deep-Sea Bacteria Which Can Prevent And Control Mycotoxigenic Fungi

Due to the impact of global warming, drought and other factors, pollution of edible and forage agricultural products caused by mycotoxins has become a more and more serious problem. Reports on mycotoxigenic fungi are increasing worldwide. The ocean contains abundant biological resource. Researchers have found several bioactive substances from metabolites of marine microorganisms with unique chemical structure, no cross reaction with toxic fungi and rich antibacterial mechanism, which could be used to prepare various biopesticides and antagonistic agents. Deep-sea bacteria is a kind of marine microorganisms with great research value which metabolites have great application prospects in research on preventing and controlling mycotoxigenic fungi.In order to obtain high-activity strains which could prevent and control toxogenic fungi and acquiring efficient and harmfulless fermentation through spray drying or freeze drying.In this experiment, 139 stains from South Atlantic deep-sea with high activity have been found through visualizing screening plate method in previous work in our laboratory. Tip-culture method was used to screening deep-sea bacteria which can effectively inhibit the growth of Fusarium graminearum, Aspergillus parasiticus NFRI-95 and aflatoxin production. Result shows that there were 38 strains could effectively inhibit the growth of Fusarium graminearum, 8 strains could effectively inhibit the growth of Aspergillus parasiticus NFRI-95 and 23 strains could effectively inhibit aflatoxin production. Among these high-activity strains, 16-2T, 15-3T, 12-80-1M, 16-40-11 F, 3-2T and 21-40-5F showed efficient inhibition of Fusarium graminearum, Aspergillus parasiticus NFRI-95 and aflatoxin.18 strains were selected from high-activity strains which obtained from second screen.18 spray-drying powder samples and 7 freeze-dying powder samples was produced by spray drying and free drying of zymotic fluid. The tip-culture method was used to detect the inhibitory activity of Aspergillus parasiticus NFRI-95 and. aflatoxin production, result shows that there were 17 samples had the similar inhibition rate of their zymotic fluid,the IC50 of spray-drying powder samples FF3、13-6T、ZC4H、8-5E4、4-7E4、FA13 and freeze-dying powder samples 8-5E4, 4-7E4, 12-2E4, FA13, ZL4, 9-9E to the growth of Aspergillus parasiticus NFRI-95 and. aflatoxin production is lower than Sodium Diacetate.In order to evaluate its application value, Researchers continued to study Biological safety of dry powder samples with high bioactivity. We carried out tests on antibacterial activity of spray-drying and freeze-drying samples against 5 kinds of bacteria, Escherichia coli, Staphylococcus aureus, Enterobacter aerogenes, bacillus coli, Candida albicans, hematotoxicity and cytotoxicity of 9 spray-drying samples. The results show that no powder samples has inhibitory function on 5 kinds of bacteria, compared to the control drug Sodium Diacetate, the spray-drying samples ZL4、MM6、MHE12 showed a lower hemolysis rate, the spray-drying samples FA13, 9-9E, ZL4, 4-7E4, FF3, 8-5E4, 12-2E4, ZC4 H and 13-6T on cytotoxicity of human lung fibroblast HFL1 and normal hepatocytes L-02 are lower.The metabolites of deep-sea bacteria have great potential in the prevention and control of mycotoxigenic fungi.