Application of mutated recombinant horseradish peroxidase (HRP) for phenol removal from refinery effluents is reported. Recombinant HRP produced in Escherichia coli suffers from the disadvantage of lacking glycosylation, which affects its catalytic efficiency and stability toward inactivating parameters such as increased temperature and enhanced amounts of hydrogen peroxide. In the present study, the previously reported variant (in which Asn268 was substituted with Asp, N268D) with improved stability characteristics and catalytic efficiency was used to remove phenol from a petroleum refinery effluent. The presence and removal of phenol was studied by high-performance liquid chromatography; the precipitated oxidized phenol was also observed and removed from the sample by centrifugation. Results showed that the N268D variant can remove 61%, 67%, and 81% of phenol from effluent in 1, 2, and 16 H, respectively. By exploiting the N268D mutant, removal of 50% phenol could be achieved in 42 Min, which was more than 22 times less than the treatment time required by native recombinant enzyme.
Keywords: phenol removal; recombinant horseradish peroxidase; site-directed mutagenesis; wastewater treatment.
© 2013 International Union of Biochemistry and Molecular Biology, Inc.