Tyrosinase Enzyme Purification and Immobilization from Pseudomonas sp. EG22 Using Cellulose Coated Magnetic Nanoparticles: Characterization of Bioactivity in Melanin Product

Melanin is a brown-black pigment produced by a variety of organisms and has significant roles in various biological processes such as insect cuticle sclerotization, wound healing, and fruit ripening. The tyrosinase enzyme catalyzes the conversion of tyrosine to melanin. Research on this enzyme and its derivatives has revealed promising uses in the pharmaceutical and biotechnology sectors. The aim of this research is to purify and immobilize the tyrosinase enzyme from Pseudomonas sp. EG22 using cellulose-coated magnetic nanoparticles. Various techniques, such as UV-visible spectroscopy, transmission electron microscopy (TEM), Zeta Sizer Nano ZS, and FTIR, were utilized to examine the synthesized nanoparticles. According to the findings, the nanoparticles exhibited a spherical shape with an average diameter of 12 nm. Furthermore, they possessed a negative surface charge, as evidenced by a polydispersity index (PDI) of 0.260 and a surface potential of -55.7 mV. The antibacterial and anticancer bioactivity of the enzyme's melanin product is also investigated. Results of the study indicated optimum tyrosinase activity at pH 6 and 35°C and increased with increasing tyrosine concentration. The results indicate that by immobilizing the tyrosinase enzyme on cellulose coated magnetic nanoparticles, its stability can be improved, enabling longer usage. Moreover, this method could prove beneficial in increasing the production of melanin. Produced melanin showed potential antibacterial activity against multi-drug resistant strain of Citrobacter freundii . The potential of melanin pigment to decrease cell survival and induce apoptosis in initiation cells was demonstrated. When treated with the IC 50 concentration, HepG2 cells showed reduced resistance to melanin pigment.