Isolation and molecular characterization of antifungal metabolite producing actinomycete from mangrove soil

Abstract

The main object of the present study is to isolate and characterize the actinomycetes from Koringa mangrove soil samples near Kakinada, Andhra Pradesh, India. Isolated actinomycetes were assessed for antagonistic activity against various bacteria and fungi. The potent strain KMFA-1 having activity against dermatophytes Candida albicans and Pectinotrichum llanense was characterized. Based on physiological, morphological characteristics and 16s rRNA gene sequencing the isolated strain was identified as Streptomyces hydrogenans. Extraction was done with different solvents and the activity was evaluated for each solvent extract. The antibiotic that is responsible for activity is found to be highly water soluble. The bioactive metabolite present in crude supernatant was found to be stable at 80 °C for 1 h, 90% activity was retained after boiling at 100 °C for 1 h, but 53.4% activity was reduced after autoclaving (at 121 °C for 15 min). The activity was not lost when the crude supernatant was subjected to wide range of pH (2–10). Furthermore, analytical techniques must be employed to isolate the molecule of interest. The result of present study revealed that the Streptomyces hydrogenans produced an interesting antifungal metabolite. Keywords: Streptomyces, Dermatophytes, Antagonistic activity, 16S rRNA gene sequencing, Bioactive metabolite