Tyrosinase enzyme purification and immobilization from Pseudomonas sp. EG22 using cellulose coated magnetic nanoparticles: characterization and application in melanin production

Melanin is a brown-black pigment with significant roles in various biological processes. The tyrosinase enzyme catalyzes the conversion of tyrosine to melanin and has promising uses in the pharmaceutical and biotechnology sectors. This research aims to purify and immobilize the tyrosinase enzyme from Pseudomonas sp. EG22 using cellulose-coated magnetic nanoparticles. Various techniques were utilized to examine the synthesized nanoparticles, which exhibited a spherical shape with an average diameter of 12 nm and a negative surface potential of - 55.7 mV with a polydispersity index (PDI) of 0.260. Comparing the immobilized magnetic tyrosinase enzyme with the free enzyme, the study's findings showed that the immobilized tyrosinase enzyme had optimal activity at a pH of 6 and a temperature of 35 °C, and its activity increased as the concentration of tyrosine increased. The study investigated the antibacterial and anticancer bioactivity of the enzyme's melanin product and found that it exhibited potential antibacterial activity against a multi-drug resistant strain including S. aureus and E. coli. The produced melanin also demonstrated the potential to decrease cell survival and induce apoptosis in initiation cells.

Tyrosinase Enzyme Purification and Immobilization from Pseudomonas sp. EG22 Using Cellulose Coated Magnetic Nanoparticles: Characterization of Bioactivity in Melanin Product.. [DOI: 10.21203/rs.3.rs-3100351/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

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 IC50 concentration, HepG2 cells showed reduced resistance to melanin pigment.

A Convenient U-Shape Microreactor for Continuous Flow Biocatalysis with Enzyme-Coated Magnetic Nanoparticles-Lipase-Catalyzed Enantiomer Selective Acylation of 4-(Morpholin-4-yl)butan-2-ol

This study implements a convenient microreactor for biocatalysis with enzymes immobilized on magnetic nanoparticles (MNPs). The enzyme immobilized onto MNPs by adsorption or by covalent bonds was lipase B from Candida antarctica (CaLB). The MNPs for adsorption were obtained by covering the magnetite core with a silica shell and later with hexadecyltrimethoxysilane, while for covalent immobilization, the silica-covered MNPs were functionalized by a layer forming from mixtures of hexadecyl- and 3-(2-aminoethylamino)propyldimethoxymethylsilanes in 16:1 molar ratio, which was further activated with neopentyl glycol diglycidyl ether (NGDE). The resulting CaLB-MNPs were tested in a convenient continuous flow system, created by 3D printing to hold six adjustable permanent magnets beneath a polytetrafluoroethylene tube (PTFE) to anchor the MNP biocatalyst inside the tube reactor. The anchored CaLB-MNPs formed reaction chambers in the tube for passing the fluid through and above the MNP biocatalysts, thus increasing the mixing during the fluid flow and resulting in enhanced activity of CaLB on MNPs. The enantiomer selective acylation of 4-(morpholin-4-yl)butan-2-ol (±)-1, being the chiral alcohol constituent of the mucolytic drug Fedrilate, was carried out by CaLB-MNPs in the U-shape reactor. The CaLB-MNPs in the U-shape reactor were compared in batch reactions to the lyophilized CaLB and to the CaLB-MNPs using the same reaction composition, and the same amounts of CaLB showed similar or higher activity in flow mode and superior activity as compared to the lyophilized powder form. The U-shape permanent magnet design represents a general and easy-to-access implementation of MNP-based flow microreactors, being useful for many biotransformations and reducing costly and time-consuming downstream processes.

Immobilization of the Aspartate Ammonia-Lyase from Pseudomonas fluorescens R124 on Magnetic Nanoparticles: Characterization and Kinetics

Aspartate ammonia-lyases (AALs) catalyze the non-oxidative elimination of ammonia from l-aspartate to give fumarate and ammonia. In this work the AAL coding gene from Pseudomonas fluorescens R124 was identified, isolated, and cloned into the pET-15b expression vector and expressed in E. coli. The purified enzyme (PfAAL) showed optimal activity at pH 8.8, Michaelis-Menten kinetics in the ammonia elimination from l-aspartate, and no strong dependence on divalent metal ions for its activity. The purified PfAAL was covalently immobilized on epoxy-functionalized magnetic nanoparticles (MNP), and effective kinetics of the immobilized PfAAL-MNP was compared to the native solution form. Glycerol addition significantly enhanced the storability of PfAAL-MNP. Inhibiting effect of the growing viscosity (modulated by addition of glycerol or glucose) on the enzymatic activity was observed for the native and immobilized form of PfAAL, as previously described for other free enzymes. The storage stability and recyclability of PfAAL-MNP is promising for further biocatalytic applications.