Fabrication, characterization and application of laccase–nylon 6,6/Fe3+ composite nanofibrous membrane for 3,3′-dimethoxybenzidine detoxification

In this study, laccase was immobilized on nylon 6,6/Fe3+ composite (NFC) nanofibrous membrane and used for the detoxification of 3,3′-dimethoxybenzidine (DMOB). The average size and tensile strength of the NFC membrane were found to be 60–80 nm (diameter) and 2.70 MPa, respectively. The FTIR results confirm that the amine (N–H) group of laccase was attached with Fe3+ particles and the carbonyl (C=O) group of NFC membrane via hydrogen bonding. The half-life of the laccase–NFC membrane storage stability was increased from 6 to 11 weeks and the reusability was significantly extended up to 43 cycles against ABTS oxidation. Enhanced electro-oxidation of DMOB by laccase was observed at 0.33 V and the catalytic current was found to be 30 µA. The DMOB-treated mouse fibroblast 3T3-L1 preadipocytes showed maximum (97 %) cell inhibition at 75 µM L−1 within 24 h. The cytotoxicity of DMOB was significantly decreased to 78 % after laccase treatment. This study suggests that laccase–NFC membrane might be a good candidate for emerging pollutant detoxification.