Local Streptomyces strains chemical screening of bioactive secondary metabolites

New microbial metabolites are permanently needed due to the increasein resistant pathogens and evolution of novel disease. Microbial secondarymetabolites represent a large source of compounds endowed with ingeniousstructure and potent biological activities. Streptomyces strains which arebelonging to the order Actinomycetales are suprerior to other actinomycetestrains in their ability to produce large number and varieties of bioactivemetabolites. The main compounds of these secondary metabolites areantibacterial, antifungal and antitümor agents. To explore new bioactive drug,the main strategy is to search for new compounds from well known andtalented microorganism, such as StreptomycesFor this purpose, 12 local strains were isolated from rhizospheric soils ofthree endemic plants. 16S rRNA genes of isolates were amplified. According to16S rDNA sequence analyses, we conclude that these local strains belong tomember of Streptomyces genus. Nine isolates were found to have antimicrobialactivity.In this study, our aim is to describe the bioactive secondary metabolitesproduced by Streptomyces sp. CAH29 using chemical screening methodology. Theısolate was grown at five different culture medium to determine the bestantimicrobial metabolite production. Culture supernatants were extracted withorganic solvents which have different polarity. The in vitro antimicrobial activitiesof the extracts were applied to a panel of bacteria and C. albicans. Then,Streptomyces sp. CAH29 was grown in large scale in the Benett + Glucosemedium which was the best for antimicrobial metabolite production. It wasdetermined that antimicrobial metabolites of CAH29 isolate were best obtained byethylacetat. Also, The compounds produced by isolates were separated usingdichloromethane-methanol (9:1) solvent system.Compounds separated with TLC were applied to agar to test the inhibitioneffects of spots to microorganisms by using bioautography methods. The spot withRf value about 0.69 have both antibacterial and antifungal activity. To purify thiscompound, extracts loaded on columns and elution was carried out with differentcombinations of solvents such as hexane-ethylacetate, ethylacetate and methanol.Active fractions obtained from first column were combined and loaded to secondcolumn. Active fractions eluted from second column were applied to highperformance thin layer choromatography (HPTLC) plates to purify target compound.2 mg pure compound was obtained from the last step of prurification. Compoundwas treated with different chemical reagents to highligths its possible functionalgroups Pure compound was showed maximum absorbance at 270 nm. Finally, itwas determined that the compound have antimicrobial activity againistStaphylococcus aureus, Streptococcus pyogenes and Candida albicans. Thestudies on structure elucidation of pure compound are on going.