Development And Characterization Of Cross-Linked Laccase Aggregates (Lac-Cleas) From Trametes Versicolor Ibl-04 As Ecofriendly Biocatalyst For Degradation Of Dye-Based Environmental Pollutants

Extracellular laccase from Trametes versicolor IBL-04 was insolubilized in the form of cross-linked enzyme aggregates (CLEAs) for degradation of different recalcitrant dyes. Among various precipitants, polyethylene glycol (PEG) ensured the best activity recovery (72.85%) of laccase-immobilized cross-linked enzyme aggregates (Lac-CLEAs) following ammonium sulfate (63.24%), n-propanol (46.98%), tert-butanol (22.94%), and acetone (14.5%). Lac-CLEAs were catalytically more active and stable over a broader pH range as compared to the free counterpart. Free enzyme lost 70% of its relative activity at 75 degrees C, whereas the immobilized derivatives, i.e. propanol-Lac-CLEAs, AS-Lac-CLEAs, and PEG-Lac-CLEAs retained 62.69%, 68.48%, and 86.29% of their relative activities, respectively, at this temperature. Though Lac-CLEAs exhibited a reduced affinity towards its substrate, Vmax values were markedly increased compared to the free enzyme. Lac-CLEAs catalyzed 94.57%, 90.63%, and 78.72% degradation of Remazol Brilliant Blue R, crystal violet, and Reactive Black 5, respectively. A dramatic decline in the peaks after treatment confirms the Lac-CLEAs potential to remove dyes. Interestingly, the immobilized system retained more than 60% of degradation efficiency even after eight successive uses. In conclusion, the present findings suggest the potential of Lac-CLEAs to mitigate a wide range of dyes and emerging contaminants. (C) 2021 Elsevier B.V. All rights reserved.