One-pot synthesis of black biopolymeric eumelanin pigment by indigenous salt-tolerant SGM-1

For the first time, a soil-isolated indigenous salt-tolerant Pseudomonas stutzeri SGM-1 mediated one-pot synthesis of extracellular eumelanin is reported using only l -DOPA as the substrate. Biophysical characterizations of the eumelanin were performed using UV-Vis, FTIR, XRD, TGA, FESEM-EDS, DLS, and zeta potential analyses, thus confirming the colloidal microparticles as eumelanin. The synthesized eumelanin was acid-resistant, alkali-soluble, and insoluble in distilled water and many organic solvents. This one-pot synthesis method can reduce the use of hazardous chemicals and harsh extraction methods in the manufacturing and purification of eumelanin. Melanin is produced in a safe, mild process and is then well-characterized through various physicochemical studies. The novel process can be used to produce eumelanin in high quantities.