Study On Isolation And Purification Of A Novel Antifungal Antibiotic SN06

The antibiotic SN06 from the strain MY02 showed strong activity against plant pathogenic fungi such as Botrytis cintrea, F.oxysporium fsp pumpkin, Fusarium oxysporium f.sp. cucumerinum and so on. The physico-chemical characteristics of antibiotic SN06 were reported in this paper. Antibiotic SN06 was purified by solvent extraction, silica column chromatography and high performance liquid chromatography methods.The physico-chemical characteristics of antibiotic SN06 showed that it was stable in hot and alkaline conditions, but not stable in acid conditions. The bioactive compounds from the culture of the strain MY02 were extracted with different solvents at different pH. The result showed that butanol was the optimal extraction for bioactive component at pH9.0 for 3 times. The UV spectrum of the metabolite SN06 corresponded to tetraene macrolide antibiotics, which had a characteristic pentaene-type pattern with absorption maxima at 291, 304 and 318nm.After the culture of SN06 was pretreated, the antibiotic SN06 was purified by silica gel column chromatography. The concentrated residue was passed through a silica gel column. A linear gradient elution was carried out using chloroform-methanol (3:1) and chloroform-methanol-ethyl acetate: water (1:7: 0.5: 0.1), detection was done at 304nm, flow rate 1.2mlï¹’min-1, the active fractions in suitable eluent time was concentrated to dried powder by rotary vacuum evaporation and then the methanol solution of this dried powder was fractionatedby high-performance liquid chromatography (HPLC) (SHIMADZU 8810 system) with a diode array detector using a Sinochrom ODS-BP-C18 column. Analysis conditions were as follows: solvent system methanol - water (80:20 v v-1) at a flow rate of 0.4 mLï¹’min-1, with a UV detector at 304 nm. The antibiotic SN06 was composed of two components.