Studies On Fermentation, Isolation And Characterization Of A Novel Antifungal-antibiotic

Systemic fungal infection threatens sufferers' health and lives more heavily than ever. A Streptomyces strain which can produce a novel kind of antifungal-antibiotic was screened.The fermentation conditions were optimized as follows under conical beaker culture: initial pH 6.5, 30°C, inoculum percentage 10%, fermentation time 72h. However, the activity of antibiotic productivity was highest after 52h culture in the reversed jet loop reactor (JLR), and with the same K_La, JLR was more fit for antifungal-antibiotic fermentation than continuous stirred tank reactor (CSTR), because the potency of fermentation liquor and the morphology of mycelium with JLR were much higher than those with CSTR.The physical and chemical properties of the antibiotics were also investigated. The results showed the antibiotic was stable in hot and acid conditions, but not stable in an alkaline one, and had polarity. By UV scanning, its absorption peak was observed at 270nm.After pretreatment of fermentation liquor, solvent extraction, ion-exchange chromatography and macroporous resin adsorption chromatography were used one by one to purify the antibiotic primarily. Then, the operating conditions for ion-exchange chromatography were optimized as follows: initial pH 2.0, flow rate 2BV/h for adsorption, 1BV/h for desorption, 0. 6mol/L NH₃H₂O solution as the mobile phase.