Efficient degradation of various emerging pollutants by wild type and evolved fungal DyP4 peroxidases

Abstract

The accumulation of emerging pollutants in the environment remains a major concern as evidenced by the increasing number of reports citing their potential risk on environment and health. Hence, removal strategies of such pollutants remain an active area of investigation. One way through which emerging pollutants can be eliminated from the environment is by enzyme-mediated bioremediation. Enzyme-based degradation can be further enhanced via advanced protein engineering approaches. In the present study a sensitive and robust bioanalytical liquid chromatography-tandem mass spectrometry (LCMSMS)-based approach was used to investigate the ability of a fungal dye decolorizing peroxidase 4 (DyP4) and two of its evolved variants—that were previously shown to be H2O2 tolerant—to degrade a panel of 15 different emerging pollutants. Additionally, the role of a redox mediator was examined in these enzymatic degradation reactions. Our results show that three emerging pollutants (2-mercaptobenzothiazole (MBT), paracetamol, and furosemide) were efficiently degraded by DyP4. Addition of the redox mediator had a synergistic effect as it enabled complete degradation of three more emerging pollutants (methyl paraben, sulfamethoxazole and salicylic acid) and dramatically reduced the time needed for the complete degradation of MBT, paracetamol, and furosemide. Further investigation was carried out using pure MBT to study its degradation by DyP4. Five potential transformation products were generated during the enzymatic degradation of MBT, which were previously reported to be produced during different bioremediation approaches. The current study provides the first instance of the application of fungal DyP4 peroxidases in bioremediation of emerging pollutants.

A project‐oriented biochemistry laboratory for protein engineering and structure–function using small laccase enzyme from Streptomyces coelicolor

“…The scope of mutational exploration can further be expanded by including protein engineering techniques like multiple mutations at the same time and by directed evolution 23 . The experimental exercise can also be extended to examine other physical properties, such as pH optima and thermal stability, that are attributed due to protein mutations 24 . Extreme thermal stability, versatility, and ease of characterization made SLAC an ideal enzyme to use in an undergraduate laboratory setting for various experimental purposes 25 .…”

Citrus limon peroxidase-assisted biocatalytic approach for biodegradation of reactive 1847 colfax blue P3R and 621 colfax blue R dyes

“…The process of dye decolorization with Citrus limon peroxides was used in different experiments to determine the varying effect of reaction variables within ideal reaction mixtures. The first pH was optimized, ranging from pH (2)(3)(4)(5)(6)(7)(8)(9)(10). Similar experiments were conducted to optimize temperature (25 °C-95 °C), enzyme dose (0.05-0.2), and H 2 O 2 concentration (0.05-0.2 mM).…”

“…For optimal pH, the behavior of Citrus limon peroxidase (CLP) was shown through graph Fig. 1a utilizing pH buffers raging (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). At pH 5, CLP activity was observed at its peak.…”

“…1b, pH stability trend was shown for the enzyme. The pH stability experiment revealed that the partly purified peroxide was stable throughout a wide pH range (3)(4)(5)(6)(7)(8)(9)(10)(11)(12).…”

“…Methods for detecting as well as remediation of dye contaminants are constantly being investigated. The development of several remediation methods to efficiently remove dye containments has made significant progress [6,7,8].…”