Quantitative structure-biotransformation relationships of organic micropollutants in aerobic and anaerobic wastewater treatments

• Published in: The Science of the total environment 2024-02, Vol.912, p.169170-169170, Article 169170
• Main Authors: Wang, Lianxu, Lei, Zhen, Yun, Sining, Yang, Xiaohuan, Chen, Rong
• Format: Article
• Language: English
• Subjects: Aerobic and anaerobic conditions; Biotransformation; chemical structure; Electrophilicity index; environment; enzymes; Kinetics; Lewis acids; pollutants; prediction; QSBR; reaction kinetics; wastewater; wastewater treatment
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.169170

Biotransformation is one of the dominant processes to remove organic micropollutants (OMPs) in wastewater treatment. However, studies on the role of molecular structure in determining the biotransformation rates of OMPs are limited. We evaluated the biotransformation of 14 OMPs belonging to different chemical classes under aerobic and anaerobic conditions, and then explored the quantitative structure-biotransformation relationships (QSBRs) of the OMPs based on biotransformation rates using valid molecular structure descriptors (electrical and physicochemical parameters). Pseudo-first-order kinetic modeling was used to fit the biotransformation rate, and only 2 of the 14 OMPs showed that the biotransformation rate constant (kbio) values were higher under anaerobic conditions than aerobic conditions, indicating that aerobic conditions were more favorable for biotransformation of most OMPs. QSBRs infer that the electrophilicity index (ω) is a reliable predictor for OMPs biotransformation under aerobic conditions. ω corresponds to the interaction between OMPs and microbial enzyme active sites, this process is the rate-limiting step of biotransformation. However, under anaerobic conditions the QSBR based on ω was not significant, indicating that specific functional groups may be more critical than electrophilicity. In conclusion, QSBRs can serve as alternative tools for the prediction of the biotransformation of OMPs and provide further insights into the factors that influence biotransformation. [Display omitted] •Only 2 of the 14 OMPs of kbio values were higher under anaerobic conditions than aerobic conditions.•The QSBRs for biotransformation of OMPs were developed.•ω is a reliable predictor for OMPs biotransformation under aerobic conditions.•The QSBRs help understand the mechanisms of OMPs biotransformation.