Enhanced catalytic potentiality of Ganoderma lucidum IBL-05 manganese peroxidase immobilized on sol-gel matrix

Sol-gel immobilization is an efficient approach to improve the catalytic and life-time properties of biocatalyst. A monomeric 43 kDa manganese peroxidase (MnP) from Ganoderma lucidum IBL-05 was immobilized using hydrophobic sol-gel matrix of tetramethoxysilane and propyltrimethoxysilane. The method led to very effective MnP immobilization (91.0%), and imparted remarkable stability to the enzyme (82.7 +/- 0.9% after 2 months of storage at 4 degrees C). The optimum pH was 5.0 and 4.0 for soluble and sol-gel immobilized MnP, respectively. Sol-gel encapsulated MnP exhibited 43% residual activity at 50 degrees C, whereas the free enzyme lost its activity completely after 72 h. After 5 h reaction time, textile wastewater effluents were decolorized to different extents (with a maximum of 93.92%) by immobilized MnP. Operational stability of the entrapped MnP was significantly improved after immobilization, and it retained more than 70% of original activity after three repeated uses for the tested effluents. The chemical oxygen demand (COD) and total organic carbon (TOC) of maximally decolorized effluents were below the permissible limits. The cytotoxicity evaluated through Allium cepa and brine shrimp lethality tests was considerably reduced after treatment with immobilized MnP. The broader pH stability, better thermo- and storage stability, and high catalytic activity are the attractive features of immobilized MnP that make it a promising candidate for environmental biotechnology. (C) 2016 Elsevier B.V. All rights reserved.