Mass production of pure gibberellin A(1) by Phaeosphaeria sp L487 and the fungal preparation of [U-C-13]gibberellin A(1)

The mass production of pure gibberellin A(1) (GA(1)) by shake-culturing Pha eosphaeria sp. L487 was investigated. Its GA(1) production was markedly inf luenced by natural nitrogen sources and NH4NO3. When the fungus was culture d in an 8% glucose-1.5% oatmeal-0.1% NH4NO3-0.5% KH2PO4-0.1% MgSO4. 7H(2)O medium for 3 weeks, the amount of GA, in the culture filtrate was up to ca. 200 mug/ml: the addition of safflower oil to the culture medium two weeks after inoculation prolonged the GA(1)-production period to produce 300 mug/ ml. Further preparation of [U-C-13]GA(1) as a tool for the analysis of a co mplex of GA(1) and its binding protein was attempted by using the fungus. T he fungal culture in a [U-C-13]glucose-oatmeal medium gave 6 mg of crystall ine C-13-enriched GA(1). Its C-13-enrichment of ca. 75% and (1)J(CC) values were determined by NMR spectrometry.