Screening Of GinkgolideB-Producing Endophytic Fungi And Optimization Of Cultivation Conditions

Flavonoids and ginkgolides, the main effective constituents, can aggrandize the blood vessel, increase the outflow of blood, decrease the resisting force of cerebrovascular, and surppress thrombisis. GinkgolideB especially is the most effective agonist of platelet activating factor (PAF) and now become a hot research issue in the medicine field of the world.There exists symbiosis between endophytic fungi of plants and their hosts, now that endophytic fungi live in botanical tissues for a long period of time, and evolve together with their hosts. Many endophytic fungi can produce some compounds with novel structure and specific bioactivity.In this paper, endophytic fungi of Ginkgo biloba L. were studied, from which the ginkgolideB-producing strains were screened orientationally, by means of analyzing their cellular metabolites from trial-strains, and its cultivation conditions were optimized. The results of this study were as follows:1. 109strains endophytic fungi were isolated from the different part of Ginkgo biloba tree, among which, 33strains were isolated from foot, 15 from bark, 57 from leaf and 4 from fruit.2. 16 strains of the isolated endophytic fungi were found having the same mobility rate with standard substance of GinkgolideB, further HPLC analysis showed that only 3 of the 16 have the same retain time with standard substance of GinkgolideB, strain G10 was confirmed its capacity of producing GinkgolideB.3. The 3 strains (G10, Y30 and Y40) of the isolated endophytic fungi were respectively identified as Oospora wallr., sirodesmium de Not and Penicillium LK.ex Fries based on morphological study.4. The fermentation medium for G10 was confirmed. The medium components were sugar 40g/L, NaNO₃1.73g/L, K₂HPO₄0.91g/L, MgSO₄.7H₂O 0.5g/L, KCl 0.5g/L, FeSO₄.7H₂O 0.01g/L. Using this fermentation medium, the biomass of G10 can reach 14.8g/L.5. The fermentation conditions for G10 were confirmed. The fermentation conditions were inoculum amount 7%, rotation speed 180r/min, temperature 24.5℃, initial pH7.5and medium volume 72ml/250ml. Under this fermentation conditions, the biomass of G10 can reach to 17.2g/L.