Unveiling the enhancement mechanisms of algogenic extracellular organic matters on chlortetracycline photodegradation: Constitutive relationships of compound components and reactive oxygen species generation

Longfei Kang; Yixin Jiang; Yajun Tian; Jinru Zou; Li Feng; Yongze Liu; Qi Han; Liqiu Zhang

doi:10.1016/j.scitotenv.2023.167015

Unveiling the enhancement mechanisms of algogenic extracellular organic matters on chlortetracycline photodegradation: Constitutive relationships of compound components and reactive oxygen species generation

Sci Total Environ. 2024 Jan 1:906:167015. doi: 10.1016/j.scitotenv.2023.167015. Epub 2023 Sep 19.

Authors

Longfei Kang¹, Yixin Jiang², Yajun Tian³, Jinru Zou², Li Feng², Yongze Liu², Qi Han², Liqiu Zhang⁴

Affiliations

¹ Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China. Electronic address: kangxiaowu@bjfu.edu.cn.
² Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China.
³ College of Environment, Zhejiang University of Technology, Chaowang Road 18, Hangzhou 310014, China.
⁴ Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China. Electronic address: zhangliqiu@bjfu.edu.cn.

PMID: 37734609
DOI: 10.1016/j.scitotenv.2023.167015

Abstract

Algogenic extracellular organic matters (EOMs) have been found to play a crucial role in the photodegradation of antibiotics. However, the specific molecular structure compositions of EOMs have not been fully characterized, and the intrinsic association between the structure and the production of ROS remains unclear. In this study, EOMs from Chlorella Vulgaris were characterized using FT-ICR-MS. Based on the FT-ICR-MS results, nine representative model compounds (MCs, i.e., benzene, naphthalene, anthracene, phenanthrene, glucose, l-glutamic, triglyceride, tannic and lignin) were applied to investigate the physicochemical properties of EOMs and the ROS changes induced by the photoreaction of chlortetracycline (CTC). With the help of quenching assays, nine MCs were classified into prone-ROS and non-prone-ROS fractions. Prone-ROS compounds generate O₂^- upon electron transfer to ³O₂, which then produces ·OH after disproportionation to generate hydrogen peroxide. The formation of ¹O₂ is attributed to energy transfer from prone-ROS to ³O₂. Density functional theory revealed that prone-ROS exhibited higher reactivity compared to non-prone-ROS, this finding is as well supported by the result of steady-state photolysis measurement. Our study gives a new insight into photochemical fate of CTC in aquatic environments, providing theoretical basis for assessing antibiotics' ecological risk accurately.

Keywords: Chlortetracycline; Extracellular organic matters; Photolysis; Reactive oxygen species; Triplet excited state.

MeSH terms

Anti-Bacterial Agents
Chlorella vulgaris*
Chlortetracycline* / chemistry
Photolysis
Reactive Oxygen Species / chemistry
Water Pollutants, Chemical* / analysis

Substances

Chlortetracycline
Reactive Oxygen Species
Anti-Bacterial Agents
Water Pollutants, Chemical