Microbial Synthesis of Melanin by Bacillus proteolyticus MITWPUME1: Isolation, Characterization, and Potential Application

Melanin pigment has diverse chemical and biological functions, that makes this molecule vital for potential applications in various fields. Microbial synthesis of melanin offers numerous advantages over chemical methods, including sustainability and cost-effectiveness. In the presented study, Bacillus proteolyticus MITWPUME1, an isolate of the Mimosa pudica plant’s rhizospheric zone was found to be a potential producer of melanin, yielding 355 g/L with L-tyrosine supplemented media. Extracted melanin exhibited its peak absorption at wavelength 220 nm. The FTIR peaks’ spectrum confirmed the presence of biomolecule-melanin. The biomolecule showed solubility in sodium hydroxide, ammonium hydroxide, and chloroform, while found to be insoluble in water, ethanol, and methanol. It shows precipitation with hydrochloric acid and decolorization with hydrogen peroxide. On the other hand, it showed stability across a broad range of pH and temperature, indicating its compatibility with a diverse range of industrial applications. The Sun Protective Factor (SPF) was found to be 6.15 and antioxidant activity 18.95%. These two important properties highlight the applicability of the biomolecule-melanin in the field of cosmetics. Thus, Bacillus proteolyticus MITWPUME1 emerges as a promising candidate for melanin producer with desired physicochemical properties, holding promise for other diverse agricultural, and biomedical applications.