Study On Culture Conditions And Antifungal Activity Of Marine Endophytic Fungi A44

The marine microorganisms are the important members of the marine organism. They are capable of producing a lot of bioactive substance that are different from that produced by terrestrial organisms and constitute a new biomedical resource .The bioactive substances produced by the marine microorganisms include new antibiotics, antitumour agents, unsaturated fatty acids, enzymes, enzyme inhibitors, vitamins, toxins etc. The marine microorganisms are becoming a hot research field of marine drug.An strain (A44) that is antagonistic against fungi was isolated from coastal Arundo donax in the Yellow Sea of China..Culture conditions and culture medium were investigated to obtain their effects on cell growth and metabolites anfifungul activity of A44 strain., in hope that a high-potency bioactive substances could be found. The results showed that the strongest antifungul activity from A44 strains was obtained when it was cultured in the improved liquid medium based on PDA (liquid medium based on 20% PDA, 3%glucose and 0.3% peptone and 4%NaCl and 0.002%FeSO4) with initial pH 6.0 and the size of 100ml in 500ml Erlenmeyer flask at 165rpm and 28℃ for 72h..It was found that the form rate of metabolic product was related partly with the grow rate, their equation was γ p =50.05 γ x+0.00034Cx:this paper was activity study on the fermentation liquid from A44 by antifungal spectrum, inhibitory to mycelium growth, fermentation liquid on spore germination, the dual culture. The results showed that the fermentation liquid from A44 showed strong inhibitory effect on mycelium growth and on spore germination with tower germination rate against pathogenic funguses (Alternarina.alternate . Fusarium oxysporium .f. .sp.cucumerium, Fusarium oxysporium.f.sp.niveun , et al). The effects still reserved even if the fermentation liquid from A44 was diluted with 160 of dilution rate. The experiments carried out by pairing culture demonstrated that theantagonistic mechanism appeared to be competitive growth, and antibiosis.