Transformation of atenolol by a laccase-mediator system: Efficiencies, effect of water constituents, and transformation pathways

Yiping Feng; Mengyao Shen; Zhu Wang; Guoguang Liu

doi:10.1016/j.ecoenv.2019.109555

Transformation of atenolol by a laccase-mediator system: Efficiencies, effect of water constituents, and transformation pathways

Ecotoxicol Environ Saf. 2019 Nov 15:183:109555. doi: 10.1016/j.ecoenv.2019.109555. Epub 2019 Aug 13.

Authors

Yiping Feng¹, Mengyao Shen², Zhu Wang³, Guoguang Liu²

Affiliations

¹ Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China. Electronic address: ypfeng@gdut.edu.cn.
² Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China.
³ Research Institute of Environmental Studies at Greater Bay, Rural Non-point Source Pollution Comprehensive Management Technology Center of Guangdong Province, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China.

PMID: 31419699
DOI: 10.1016/j.ecoenv.2019.109555

Abstract

In this study, we investigated the transformation of atenolol (ATL) by the naturally occurring laccase from Trametes versicolor in aqueous solution. Removal efficiency of ATL via laccase-catalyzed reaction in the presence of various laccase mediators was examined, and found that only the mediator 2, 2, 6, 6-tetramethyl-1-piperidinyloxy (TEMPO) was able to greatly promote ATL transformation. The influences of TEMPO concentration, laccase dosage, as well as solution pH and temperature on ATL transformation efficiency were tested. As TEMPO concentrations was increased from 0 to 2000 μM, ATL transformation efficiency first increased and then decreased, and the optimal TEMPO concentration was determined as 500 μM. ATL transformation efficiency was gradually increased with increasing laccase dosage. ATL transformation was highly pH-dependent with an optimum pH of 7.0, and it was almost constant over a temperature range of 25-50 °C. Humic acid inhibited ATL transformation through competition reaction with laccase. The presence of anions HCO₃^- and CO₃^2- reduced ATL transformation due to both anions enhanced solution pHs, while Cl^-, SO₄^2-, and NO₃^- at 10 mM showed no obvious influence. The main transformation products were identified, and the potential transformation pathways were proposed. After enzymatic treatment, the toxicity of ATL and TEMPO mixtures was greatly reduced. The results of this study might present an alternative clean strategy for the remediation of ATL contaminated water matrix.

Keywords: Atenolol; Laccase-catalyzed reaction; Mediator; Transformation pathways; Transformation products.

MeSH terms

Atenolol / analysis*
Atenolol / metabolism
Catalysis
Cyclic N-Oxides / chemistry*
Humic Substances / analysis
Laccase / metabolism*
Oxidation-Reduction
Temperature
Trametes / enzymology
Water Pollutants, Chemical / analysis*
Water Pollutants, Chemical / metabolism
Water Purification / methods*

Substances

Cyclic N-Oxides
Humic Substances
Water Pollutants, Chemical
Atenolol
Laccase
TEMPO