Fabrication of thermostable and reusable nanobiocatalyst for dye decolourization by immobilization of lignin peroxidase on graphene oxide functionalized MnFe₂O₄ superparamagnetic nanoparticles

In view of the potential applications of immobilized enzymes, partially purified Lignin Peroxidase (LiP) from Pseudomonas fluorescens LiP-RL5 was immobilized on Graphene Oxide functionalized MnFe₂O₄ nanoparticles (10 nm, synthesized by sol-gel auto-combustion) to fabricate a new hyperactive and thermostable nanobiocatalyst and thereafter characterized by using standard techniques. Immobilized LiP was quite stable at 50 °C with the half-life of 14 h and showed higher tolerance towards various metal ions and solvents than free LiP. Immobilized LiP retained 50% of enzyme activity even after nine consecutive runs. When tested against various textile dyes, the immobilized LiP was found quite effective with higher dye decolourization efficiency (up to 88%) within 1 h of incubation at 30 °C. The results of this research effort confirmed that the immobilization of LiP and fabrication of nanobiocatalyst increase the efficacy, stability, and reusability of the enzyme which could be efficiently utilized under harsh industrial conditions.