Separation Of Biologically Active Components Of Non-hygroscopic Streptomyces

A strain of Streptomyces ahygroscopicus was isolated from soil.We have detected its antimicrobial activity before this project.The results of antimicrobial activity tests showed it had strong antimicrobial activity.Meanwhile preliminary chemical analysis and test indicated the chemical structure of its active compound was different to other compounds from Streptomyces.In this study,several chromatographic techniques and spectroscopic methods were used to investigate the separation and structure identification of antimicrobial compounds from the strain.Several chromatographic techniques were used to study the separation and purification of antimicrobial compound.Fermentation broth of S.ahygroscopicus was adsorbed by AB-8 macroporous resin,eluted with H2O-Ethanol(1:0,1:3,2:2,3:1,0:1).Five fractions were obtained.The fractions eluted by 75%ethanol and 100%ethanol were combined as a separation objective.Then it was separated by column chromatography of silica gel,Sephadex LH-20 column chromatography,Preparative thin layer chromatography and high performance liquid chromatography.Five compounds were obtained.The active compound from S.ahygroscopicus was identified by spectroscopic techniques,such as mass spectrometry,Hydrogen nuclear magnetic resonance spectrum(H-NMR),Carbon nuclear magnetic resonaofnce spectrum(C-NMR).Its molecular weight was 353.13341 and its molecular formula was C20H19NO5.Antibacterial activities were evaluated for compound 5 by 96-well plate serial dilutions combined with MTT bioautography.Bacillus subtilis and Pseudomonas solanacearum were as test strains.The results showed that minimum inhibitory concentration(MIC)of the compound 5 against P.solanacearum was 16μg/ml and MIC value of compound 5 against B.subtilis was 64μg/ml.Streptomycin sulfate was chosen as positive control.MIC values against both P.solanacearum and B.subtilis were 16μg/ml.