Immobilized Cerrena sp. laccase: preparation, thermal inactivation, and operational stability in malachite green decolorization

Abstract

Laccases are polyphenol oxidases with widespread applications in various industries. In the present study, the laccase from Cerrena sp. HYB07 was immobilized with four methods, namely entrapment in alginate, covalently binding to chitosan as well as formation of cross-linked enzyme aggregates (CLEAs) and magnetic CLEAs (M-CLEAs). The activity recovery rates of the immobilized laccases ranged from 29% to 68%. Immobilization elevated the reaction temperature optimum and reduced substrate specificity, but not necessarily the turnover rate. pH stability of immobilized laccases was improved compared with that of the free laccase, especially at acidic pH values. Thermal inactivation of all laccases followed a simple first-order exponential decay model, and immobilized laccases displayed higher thermostability, as manifested by lower thermal inactivation rate constants and longer enzyme half-life time. Operational stability of the immobilized laccase was demonstrated by decolorization of the triphenylmethane dye malachite green (MG) at 60 °C. MG decolorization with free laccase was accompanied by a shift of the absorption peak and accumulation of a stable, colored intermediate tetradesmethyl MG, probably due to lower thermostability of the free laccase and premature termination of the degradation pathway. In contrast, complete decolorization of MG was achieved with laccase CLEAs at 60 °C.

Immobilization of a Laccase/2,2’-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic Acid System to Layered Double Hydroxide/Alginate Biohybrid Beads for Biodegradation of Malachite Green Dye

“…This result suggested that the Im-LMS exhibited a dye removal efficiency similar to that of the free LMS. The MG decolorization by laccase immobilized on various matrix was presented in the literature [ 36 , 37 ]. For example, the decolorization yields of MG by laccase immobilized on titanium oxide were 90% within 6 h [ 36 ].…”

“…For example, the decolorization yields of MG by laccase immobilized on titanium oxide were 90% within 6 h [ 36 ]. The decolorization yields of MG by cross-linked laccase aggregates were 95% within 6 h [ 37 ]. Moreover, the decolorization yields of MG by coimmobilized Laccase-acetylacetone system were 95% within 48 h [ 14 ].…”

3D Chitin Scaffolds from the Marine Demosponge Aplysina archeri as a Support for Laccase Immobilization and Its Use in the Removal of Pharmaceuticals

“…by adsorption using chitosan beads as a support. In their study, due to stabilization of the enzyme upon immobilization, the half-life of the immobilized laccase was found to be almost twice that of the free biocatalyst [68]. By contrast, in a study by Tavares et al in 2015 [69], commercial laccase was immobilized by adsorption using multi-walled carbon nanotubes.…”

CLEAs, Combi-CLEAs and ‘Smart’ Magnetic CLEAs: Biocatalysis in a Bio-Based Economy

“…Immobilization of these enzymes, for example as CLEAs or combi-CLEAs is necessary in order to be cost-effective in waste water treatment. Although it is difficult to achieve the very low enzyme costs required for commercial viability in waste water treatment in general there may very well be niche opportunities in the case of emerging micropollutants that are difficult to remove by other means For example, laccase-m-CLEAs [197,198] and a combi-m-CLEA of horseradish peroxidase and glucose oxidase [199] have been used for the decolorization of recalcitritant dyes in waste water and various reactor concepts have been considered. A laccase-m-CLEA was also used for removal of pharmaceuticals from waste water [200] and an acrylamidase m-CLEA was used to catalyze the biodegradation of acrylamide in industrial waste water [201].…”