Biosynthesis, Characterization and Antagonistic Applications of Extracellular Melanin Pigment from Marine Nocardiopsis Sps

  Context: Although there is an abundance of several microbial phyla in the oceans actinobacteria have emerged as a major source for natural products. Streptomyces sps is the widely encountered actinobacteria. Lately, Streptomyces are increasingly been used for pigment extraction. Aim: The aim herein was to extract bioactive melanin pigment from rare actinobacteria, which is a not a widespread occurrence. Materials and Methods: Marine samples were collected aseptically from the waters of the Arabian Sea, Allepey, Kerala, India. Isolation was performed by serial dilution method upon dry heat treatment and pre-enrichment technique on Actinomycetes Isolation Agar. Selected potent isolates were fermented and the pigments were extracted. Thereafter the pigment was analyzed by various techniques viz., thin layer chromatography, UV-Visible spectrophotometry and Fourier Transfer Infra Red spectroscopy. Further, the pigment was evaluated for its antibacterial, anti-biofilm and anti-quorum sensing potential. Results: The isolates were designated as JN1 and JN2 and their respective extracts JN1M and JN2M. JN1M was found to be inhibiting biofilm forming clinical isolate Staphylococcus sp. showing an activity of 64.20 ± 3.33% and pigment from JN2M 65.99± 2.81%. The melanin pigment also exhibited considerable activity against various human pathogens. The isolate JN1 was identified as Nocardiopsis dassonvillei strain JN1 (accession number: KX263302) and JN2 as Nocardiopsis sp (accession number: KX263303) by conventional and molecular techniques. Conclusion: With reference to previous reports, this is one of the very few reports of marine Nocardiopsis dassonvillei exhibiting melanin production. Thus it has established the production of melanin from rare actinomycetes, N. dassonvillei in specific.