Improving hydrogen peroxide stability of a dye-decolorising peroxidase from Irpex lacteus F17 by site-directed mutagenesis

Abstract

Il-DyP4, a dye-decolorizing peroxidase (DyP) from Irpex lacteus F17, has a strong ability to oxidise harmful aromatic compounds, implying application potential in the field of environmental protection. However, the low H₂O₂ stability of Il-DyP4 hinders its practical application. To improve the H₂O₂ stability of Il-DyP4, oxidation-sensitive amino acids including three Met, one Cys and ten Tyr residues were mutated to less easily oxidizable residues such as Leu, Val and Phe by site-specific mutagenesis. Mutation of the M207 site, located on the surface of the enzyme and far away from the haem group, improved H₂O₂ stability by 5.3-fold or more. In addition, Y234, also on the enzyme surface, was replaced with Phe and the Y234F mutant displayed 7.3-fold increased H₂O₂ stability. Furthermore, mutants M207V and Y234F were selected for the decolorization of various types of synthetic dyes, revealing high decolorization activities, especially for M207V with enhanced catalytic activity. The stable DyP mutant M207V has the potential for decolorization of industrial dye wastewater.

Keywords:

• Aromatic oxidation
• dye-decolorizing peroxidase
• enzymatic activity
• H₂O₂ stability
• Irpex lacteus
• site-directed mutagenesis

Author contributions

All authors contributed the conception and design of the study. Wenhan Huang and Jingjing He performed the experimental work and wrote the paper; Liuqing Li helped to revise the manuscript; Rong Jia conceived of the study, and participated in its design and helped to revise the manuscript. All authors read and approved the final manuscript. Wenhan Huang and Jingjing He contributed equally to this work.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The study was supported by the National Natural Science Foundation of China (31970100).