Isolation and Characterization of Novel Metal Accumulating Extracellular Protease Secreting Bacteria from Marine Coastal Region of Digha in West Bengal, India

Abstract

Problem statement: The objective of the present piece of work was to explore the existing biodiversity of protease secreting microbes in a marine ecosystem, the site selected being the coastal region of West Bengal (Digha), India. Approach: The culture dependent method was used for isolation and characterization of novel microbes from the point of biotechnological application. The isolate obtained was characterized on basis of its morphological, biochemical, physiological properties and finally its molecular identity was revealed through 16S rDNA analysis. The complete characterization would ease the application of this isolate for various purposes which would require the understanding of the detailed properties. Results: The isolation was done on milk medium while further characterization was done in Luria Bertani broth as well as Carbon Minimal Salt medium. The isolate was found to be DNase & protease positive, spore forming, Gram-positive bacilli and exhibited growth in wide range of substrates, temperature [20⁰C-40⁰C] & pH [5.5-10]. The Scanning Electron Micrograph revealed a unique pililike bridge between every 3-4 bacterial cells, which indicates the characteristic stacking pattern of growth found in certain groups of bacteria. Moreover it was found to grow in presence of a wide range of metals namely iron, lead, mercury, zinc, aluminum, copper, nickel, cadmium and silver. Energy dispersive X Ray Fluorescence analysis conducted for two of the metals, chromium and copper indicated the intracellular accumulation of these metals. Conclusion: This property provides potential for its application in remediation as well as recovery of heavy metals. The isolate with this property can be a potential candidate to carry out bioaugmentation.