Decolorization of Azo and Anthraquinone Dyes Using Recombinant Horseradish Peroxidase A2A Isoenzyme Produced by Komagataella phaffii.

Water pollution is a significant issue due to industrialization and population growth, and one of the main sources of wastewater is synthetic dyes. The textile sector is particularly affected by dyes like azo and anthraquinone dyes, which are difficult to degrade and produce toxic organic waste. Currently, synthetic dyes are processed through physical and chemical methods, which have financial and methodological disadvantages. Horseradish peroxidase (HRP) is a widely studied enzyme for purifying pollutants like dyes and phenols in wastewater. However, their high cost makes them a costly option. Recombinant protein production is suitable for the mass production of stable and resistant enzymes. In this study, the decolorization potential of recombinant HRP A2A (rHRP A2A) isoenzyme secreted by Komagataella phaffii and purified by affinity technique in a single step on Acid blue 113, Alizarin red, and Remazol brilliant blue R was presented for the first time, and the optimal conditions for the highest decolorization rate were determined. Fe²⁺ and Mn²⁺ metal ions increased enzyme activity by 158.62% and 79.54%, respectively. Color removal with 0.006 EU/mL rHRP A2A for Acid blue 113, Alizarin red, and Remazol brilliant blue R was observed at 71.27, 62.26, and 31.22%, respectively. ABTS served as a redox mediator, significantly increasing the rate of dye decolorization in a shorter period at the specified concentration.