Clean Laccase immobilized nanobiocatalysts (graphene oxide - zeolite nanocomposites): From production to detailed biocatalytic degradation of organic pollutant

In this paper, the Laccase enzyme was covalently immobilized onto nanoparticle of zeolite (NZ)-graphene oxide (GO) composites to prepare the novel nanobiocatalysts for degrading Direct Red 23 as an organic pollutant. Graphene oxide-zeolite (GZ) nanocomposites with 0.03, 0.05, and 0.07 g amounts of GO (denoted as GZ3, GZ5, and GZ7, respectively) were synthesized. The materials were silanized for synthesizing SNZ, SGZ3, SGZ5, and SGZ7. The glutaraldehyde as a cross-linking agent was used to prepare GSNZ, GSGZ3, GSGZ5, and GSGZ7. Laccase was immobilized on them for synthesizing Laccase immobilized nanobiocatalysts including LIGSNZ, LIGSGZ3, LIGSGZ5, and LIGSGZ7. The SEM, FESEM, XRD, FTIR, TEM, HPLC, and UV–vis were used for characterizing materials and dye degradation. The effects of GO ratio, catalyst dosage, dye concentration and pH on pollutant biodegradation were evaluated and optimized. The nanobiocatalysts indicated well reusability over five cycles, high storage stability, and thermal stability.