Sulfamethoxazole and isoproturon degradation and detoxification by a laccase-mediator system: Influence of treatment conditions and mechanistic aspects

Abstract

a b s t r a c tThe potential of laccase-mediator systems (LMS) for the removal and detoxification of two wastewater micropollutants, the antibiotic sulfamethoxazole (SMX) and the herbicide isoproturon (IPN), was assessed. The influence of various parameters on micropollutant oxidation rates, such as pH, mediator, enzyme and pollutant concentrations, was investigated with three mediators: 2,2 -azinobis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), syringaldehyde (SA) and acetosyringone (AS). Both pollutants were completely transformed within a few hours in presence of laccase and ABTS, as well as, for SMX, in presence of AS or SA. The three mediators were consumed during the reaction (no catalytic reactions observed), at a ratio mediator/pollutant between 1.1 and 16 mol/mol. Faster oxidation kinetics were observed at lower pH values, but also higher mediator/pollutant ratios were required. Several transformation products were formed, including cross-coupled products. Product mixtures were always less toxic to algae than untreated pollutants. Finally, a kinetic model that could explain the experimental observations was established. Based on the findings in this study LMS appears to be a promising option to treat concentrated and potentially toxic industrial effluents.

Biocatalytic properties of cell surface display laccase for degradation of emerging contaminant acetaminophen in water reclamation

“…Laccases (EC 1.10.3.2) are a promising group of oxidoreductases that have high activity in oxidizing phenolic compounds and arylamine, including phenols, polyphenols, methoxy‐substituted phenols, aromatic and aliphatic amines, by using molecular oxygen as the electron acceptor without the need for cofactors (Strong & Claus, ; Thakur, Patel, Gupte, & Gupte, ). Prior studies have demonstrated the use of laccases for effective degradation of emerging contaminants, such as endocrine disruptors (bisphenol A [Zdarta, Antecka et al, ] and triclosan [Le et al, ]), pharmaceuticals (sulfamethoxazole [Margot, Copin, von Gunten, Barry, & Holliger, ] and naproxen [Tran, Urase, & Kusakabe, ]), and pesticides (bromofenoxim [Torres‐Duarte, Roman, Tinoco, & Vazquez‐Duhalt, ] and carbofuran [Wang, Liu, Yao, Zhang, & Bao, ]). However, using free enzymes faces challenges including short enzyme lifetimes, time‐consuming and expensive purification processes, and nonreusability (Sheldon & van Pelt, ).…”

Laccase–syringaldehyde-mediated degradation of trace organic contaminants in an enzymatic membrane reactor: Removal efficiency and effluent toxicity

“…Highly reactive phenoxyl radicals are produced due to oxidation of SA by laccase. These radical species can be consumed as they react with TrOCs (Margot et al, 2015). However, due to continuous addition of SA in excess, copious amount of reactive radical species are likely to be produced.…”

Degradation of Pharmaceuticals and Personal Care Products by White-Rot Fungi—a Critical Review

“…Numbers within parenthesis indicates number of data points. Data was collected from the following studies:[82,83,84,85,103,104,105,106,107,108].…”