Optimization of cultural conditions for production of antifungal metabolites by Streptomyces gougeroti

Use of antagonist microorganisms against fungal plant pathogens is an attractive and ecologically alternative to the use of chemical pesticides. Streptomyces spp. are beneficial soil bacteria and potential candidates for biocontrol agents. Different Streptomyces species were isolated from different sources sites from soil in Damietta. During primary and secondary screening, some actinomyctes isolates showed antifungal activity against tested phyto pathogenic fungi (Penicillium italicum, Macrophomina phaseolina, Fusarium oxysporium, F. solani, Alternaria alternata, Sclerotina sclerotiorum and Rhizoctonia solani ). The results showed that the most active isolate against tested phyto pathogenic fungi Macrophomina phaseolina and Alternaria alternata was identified as Streptomyces gougeroti. Streptomyces gougeroti showed maximum antifungal activity against Alternaria alternata and Macrophomina phaseolina at 35°C ± 2, pH 6.5. Glycerol and beef extract were the best carbon and nitrogen sources used respectively.