Screening And Identification Of Scleractinia Funguswith Antibacterial Activity And Research On The Active Products

The metabolites of coral have more types and also produce lots of novel structure products.Meanwhile,marine natural products were all isolated from coral sponge and marine microbes.Some marine active products were isolated from marine organism hosts.In order to screen fungus which produce natural products,in this dissertation,we focused particularly on studies on the active isolate screening,identification,active products and optimization of fermentation conditions.The main results are as follows:(1)Screening of antimicrobial bioactivity.Sixty coral fungus strains were used to assay antimicrobial bioactivity using agar diffusion assay.Three isolates,named XWC21-10?XWC21-23 and XWC14-13,exhibited stronger and broad-spectral activities against all the six indicator bacteria.(2)Identification of 3 isolates.According to the morphological,cultural and r DNA ITS sequence analysis,active strains XWC21-10 was identified as Aspergillus terreus;active strains XWC21-23 was not identified;and active strains XWC14-13 was identified as a potential new species belonging to Arthrinium sp..According to the growth of colony diameter and hypha weight,the optimum temperature of strains XWC21-23 and XWC14-13 were 25 °C and 30 °C,respectively;optimum p H of strains XWC21-23 and XWC14-13 were p H 8.0 and p H 8.0,respectively.(3)Activities of the metabolites of 3 isolates.According to the scavenging rates of the metabolites of 3 isolates against DPPH?hydroxyl and superoxide anion free radicals,it is showed that the antioxidant activity of XWC21-10 was higher than XWC21-23 and XWC14-13.In the enzymes inhibitory experiment,there was only crude extract of strain XWC21-10 had inhibiting effect on Ach E.Bioassay of stability of active products of isolates XWC21-10?XWC21-23 and XWC14-13 against S.a and SL1.The active products from strain XWC21-10 exhibited stability on p H treatment,high temperature and ultraviolet radiation.(4)The fermentation conditions of strain XWC21-10.The experiment indicated that the optimum fermentation condition of strain XWC21-10 for producing the most active products was cultured in: optimum fermentation culture medium: maltose of 1%,soluble starch of 2%,Na H2PO4 of 0.02%,K2HPO4 of 0.06%;optimum fermentation condition: p H of 7.0-7.5,fermentation temperature of 28 °C,inoculation amount of 8%,fermentation time of 9d.It is concluded that coral fungi are variety,and are potential new microorganism resources.Meanwhile,coral fungus showed stronger bioactivities and were deserved for further study.