The oxidation of anthraquinone dye using HRP immobilized as a cross-linked enzyme aggregates

Abstract

Finding a sustainable and ecofriendly methods for recalcitrant synthetic dyes removal is a researchers major challenge. A carrier-free technique for commercial HRP immobilization is a focus of the present study. The immobilized biocatalyst, HRP-CLEAs with 580 U g-1 of the activity was obtained under the following immobilization conditions: precipitation reagent 80% ammonium sulphate, cross-linking reagent 1% of glutaraldehyde and protein-fedder, bovine serum albumin (BSA) concentration 5 mg ml-1. The obtained HRP-CLEAs showed great affinity towards model anthraquinone dye, C. I. Acid Violet 109. 88.4% of the dye was oxidized under the reaction conditions: pH 4, dye concentration 40 mg l-1, H2O2 concentration 1 mM and 0.1 U of HRP-CLEAs. The possibility of the immobilized biocatalyst application in five and eight oxidation cycles of the dye and pyrogallol (retained activity 80%), respectively, indicates that HRP-CLEAs is an efficient and environmentally friendly biocatalyst with great potential in aromatic compounds removal from wastewater. This paper is a continuation of our earlier research related to HRP from horseradish extract immobilization in the form of CLEAs and the application in the wastewater colored with a synthetic anthraquinone dye treatment.

Pronalazak održivih i ekološki prihvatljivih metoda za uklanjanje sintetičkih boja je jedan od vodećih izazova za istraživače. U ovom radu akcenat je na metodi imobilizacije bez primene nosača. Imobilisani preparat peroksidaze iz rena, aktivnosti 580 U g-1 dobijen je pod sledećim uslovima imobilizacije: taložni reagens 80% amonijum-sulfat, umrežavajući reagens 1% glutaraldehid i goveđi serum albumin koncentracije 5 mg ml-1. Dobijeni umreženi agregat peroksidaze iz rena pokazao je veliki afinitet prema model antrahinonskoj boji, C. I. AV 109. Pod optimalnim uslovima: pH 4, koncentracja boje 40 mg-1, koncentracija H2O2 i 0,1 U enzimske aktivnosti oksidovano je 88,4% ispitivane boje. Mogućnost primene imobilisanog enzima kroz pet i osam uzastopnih ciklusa oksidacije boje i pirogalola (zadržana aktivnost 80%) pokazuje da je imobilisani enzim efikasan i ekološki prihvatljiv biokatalizator koji se može koristiti u oksidaciji aromatičnih jedinjenja iz otpadnih voda. Ovaj rad predstavlja nastavak istraživanja vezanog za umrežavanje peroksidaze iz svežeg ekstrakta rena, koja se takođe pokazala kao imobilisani biokatalizator sa velikim potencijalom primene u tretmanu obojenih otpadnih voda.