Immobilization of Laccase on Magnetic Carriers and Its Use in Decolorization of Dyes

Abstract

Laccase from Trametes versicolor was immobilized on magnetic (Fe 3 O 4 ) nanoparticles and microparticles. Free and immobilized laccase had activities 163 and about 4.6 nkat mg -1 respectively. Immobilized was 125.8 µg enzyme mg -1 of nanoparticles and 13 µg enzyme mg -1 of microparticles. The K m were 10.55, 9.02 and 11.14 mmol L -1 for free laccase, immobilized on nanoparticles and immobilized on microparticles. The pH optimum after immobilization was about 0.5 pH less than before immobilization. Immobilized laccase retained 55 % (nano) and 47 % (micro) of initial activity after nine repetitions. Values of T 50 were calculated respectively for free laccase, immobilized on nanoparticles and microparticles at 54.5 °C, 57.5 °C and 46 °C. Dyes Direct Blue 78, Acid Blue 225, Reactive Red 195, Acid Blue 74, and Phenol Red were used for decolorization by free and immobilized laccase. Laccase was able to decolorize most of the dyes well.

Applications and immobilization strategies of the copper-centred laccase enzyme; a review

“…Decolourisation using physical or chemical methods such as adsorption, precipitation, chemical degradation, and photo-degradation has financial and methodological disadvantages, is time-consuming, and mostly ineffective [ 238 ]. With the stringent regulations and restrictions established for effluent discharge into the ecosystem, a number of studies have focused on microorganisms, which are able to decolourise and biodegrade these dyes [ 239 , 240 , 241 , 242 ]. Enzymatic treatment of dye effluents has gained attention because of the mild reaction conditions involved without generating any secondary pollution like toxic sludge [ 243 , 244 ].…”

Enzymatic decolourization of water using loofa sponge as cellular carrier: Immobilization and dye degradation performance

“…RBBR is a typical anthraquinone dye used in the textile industry. In order to identify the proper operating conditions, the central composite design À response surface methodology (CCS-RSM) [41,49] was applied to assess the functionalities between the adjustable variables dye concentration (10-50 mg/L), mixing time (1-5 h), mixing velocity (60-240 rpm), and degradation rate D. It is important to note that the ranges for the parameters selected for the dye removal (low dye concentration and short reaction time) coincide with typical treatment conditions at which many other treatment methods are not applicable. The tree variables were tested at five levels (À1.735, À1, 0, þ1, and þ1.735), which results in the quadratic polynomial equation according to…”

“…In addition, immobilization of enzyme is also an appropriate way to reach high bio‐catalytic activity since this will shift the enzyme kinetic parameters and strengthen the protein structure . Several studies were performed immobilizing enzymes on solid supports . Beyond the efficient contact between enzyme and reaction medium, prevention of mixing, and the enzyme replacement, the immobilization was also found to improve lifetime, catalytic stability, and storage ability …”

“…A variety of materials were used as solid carriers to immobilize laccase, e.g. ceramic honeycombs, spherical alumina pellets, polymer fibres, porous glass beads, magnetic hydrazide bead cellulose, mesostructured cellular foams, activated polyvinyl alcohol carriers, as well as cellulose nanofibre . An important geometric feature of a proper enzyme carrier is providing a high specific surface area to ensure a high enzyme loading capacity as well as a high porosity.…”

“…[5] Several studies were performed immobilizing enzymes on solid supports. [19,21,[41][42][43][44] Beyond the efficient contact between enzyme and reaction medium, prevention of mixing, and the enzyme replacement, the immobilization was also found to improve lifetime, catalytic stability, and storage ability. [45,46] A variety of materials were used as solid carriers to immobilize laccase, e.g.…”