Tyrosinase from <i>Penicillium chrysogenum</i>: Characterization and application in phenol removal from aqueous solution

Abstract

The tyrosinase of Penicillium chrysogenum strain AUMC 14100 Accession No. MN219732 was purified to homogeneity and chemically modified by N-ethylmaleimide (NEM) and 5-(dimethylamino)naphthalene-1-sulfonyl chloride (dansyl chloride, DC). The inactivation of the purified enzyme obeyed pseudo-first-order reaction kinetics in the presence of NEM and DC (1-5 mM).The rate constants of the enzyme inactivation by NEM and DC were calculated to be 0.083 mol/min and 0.0013 mol/min, respectively. The recovery of enzyme activity by the protective effect of substrate indicates a non-specific modification of the active center. The order of tyrosinase inactivation kinetics and the substrate protection revealed the essentiality of sulfhydryl and lysyl residues in the enzyme active site and its role in the enzyme catalysis. The immobilized tyrosinase on alginate showed a gradual increase in residual activity over the immobilization time until the fourth hour. The desorptivity of tyrosinase was gradually raised with higher sodium dodecyl sulfate (SDS) concentrations. The immobilized enzyme retained about 70% of its original activity after 8 repeated cycles. Thus, immobilized tyrosinase of Penicillium chrysogenum removed 75% of phenol after 8 cycles and thus seems likely to be a good candidate for phenol removal in aqueous solution.

Thiolation of Myco-Synthesized Fe3O4-NPs: A Novel Promising Tool for Penicillium expansium Laccase Immobilization to Decolorize Textile Dyes and as an Application for Anticancer Agent

“…The fungal isolates used in this work were freshly isolated from different soil samples (Benha, Egypt), and their ability to produce laccase was detected using a modified medium (MM) containing 2.0 g/L corn steep liquor; 0.07 g/L KCl; 1.2 g/L NH 4 H 2 PO 4 ; 0.5 g/L MgSO 4 •7H 2 O; 0.1 g/L FeSO 4 •7H 2 O supplemented with 0.5 mM (ABTS) on a rotary shaker (120 rpm) for 5 days at 28 • C. The mycelial pellets were excluded, washed, and homogenized in phosphate buffer (pH 5.0, 50 mM) for 30 min. Subsequently, the homogenate was centrifuged for 20 min at 10,000× g and 4 • C. The clear supernatant represented crude extract of laccase and the enzyme activity was measured according to [6].…”

“…Then, the sequences were then aligned for the multiple sequence alignment with the ClustalW muscle algorithm. The phylogenetic tree was generated using the Neighbor-Joining method with a confidence level of 1000 bootstrap replication [6,14].…”

“…The cosmetic, food, pharmaceutical, textile, printing, and leather industries are discharging recalcitrant pollutants into natural water bodies. However, water pollution produced through the discharge of untreated toxic/recalcitrant textile dyes into water bodies has severe harmful effects on the continuation of life in the specific biosphere [6,7].…”

“…The above methods mentioned for wastewater clean-up are quite expensive, limiting their actual application at large industrial scales [6,10]. In recent decades, nanocomposite, nanoparticles, and biosorbents have been widely employed for textile dyes adsorption.…”

“…Laccases catalyze the oxidation of the target pollutant coupled to the molecular oxygen reduction to water [5,13,14]. The oxidation rate of pollutants by laccase is improved through the performance of small molecular weight redox mediators [6].…”