Extraction and identification of Gancidin W from Marine Streptomyces sp. VITLGK012

Abstract

The present study was aimed to screen and identify antibacterial bioactive nitrogenous secondary metabolites produced by the marine Streptomyces sp. VITLGK012. The antibacterial potential of the extracted compound was studied using agar well diffusion method. Minimal inhibitory concentration of the compound for antibacterial activity was estimated using the plate dilution method. The isolate was characterized by morphological, biochemical and molecular taxonomy using 16S rDNA sequencing. Chloroform extract was prepared and purified by silica gel column chromatography. The nitrogenous fraction was identified with Dragondorff’s reagent. The structure of the pure compound was identified by gas chromatography coupled with mass spectrometry, Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. Crude extract of VITLGK012 showed antibacterial activity with a MIC of 0.5 mg/ml against Proteus vulgaris. VITLGK012 strain was identified to be a Streptomyces species based on 16S rDNA sequencing. Gas chromatography and mass spectrometry analysis showed the presence of more than 10 molecules in the crude extract. Based on spectroscopic analysis, the extracted compound was found to be nitrogenous in nature and was identified as gancidin W. The results of the study suggested that Streptomyces sp. VITLGK012 could be a good source for nitrogenous antibacterial secondary metabolites.