Screening and partial purification of antifungal metabolite from Streptomyces rochei MSA14: an isolate from marine mining soil of Southwest coast of India

A total of fourteen actinobacterial strains were isolated from the mining sediment of Manavalakurichi, Southeast coast of India. Primary screening results through agar well diffusion method revealed that 28.57% actinobacterial strains had in vitro antifungal activity. Most potent actinobacterial isolate MSA14 showed strongest inhibitory activity and was identified as Streptomyces rochei through morphological, physiological, biochemical and 16S rRNA gene sequence characteristics. Crude ethyl acetate extract of S. rochei exhibited wide spectrum antifungal activity which was ranged between 12 and 17 mm. Further evaluation of Minimum inhibitory concentration (MIC) and Minimum fungicidal concentration (MFC) showed the values ranged from 50 to 200 and 100 to 200 μg/ml, respectively. Partial purification of crude extract through TLC using various gradient solvent system recorded different spots of active principles with the respective Rf values between 0.22 and 0.90. TLC autobiography assay evidenced that, spot with the Rf value of 0.54 had promising antagonistic activity.