Biotransformation of organic micropollutants by anaerobic sludge enzymes. (1st April 2019)

• Record Type: Journal Article
• Authors: Gonzalez-Gil, Lorena; Krah, Daniel; Ghattas, Ann-Kathrin; Carballa, Marta; Wick, Arne; Helmholz, Lissa; Lema, Juan M.; Ternes, Thomas A.
• Is Part Of: Water research. Volume 152(2019)
• Page Start: 202
• Page End: 214
• Publication Date: 2019-04-01
• Subjects: Anaerobic digestion -- Degradation -- Enzymatic transformation -- Enzymatic pathways -- Pharmaceuticals -- Sewage treatment plant; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2018.12.064
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Biotransformation of organic micropollutants (OMPs) in wastewater treatment plants ultimately depends on the enzymatic activities developed in each biological process. However, few research efforts have been made to clarify and identify the role of enzymes on the removal of OMPs, which is an essential knowledge to determine the biotransformation potential of treatment technologies. Therefore, the purpose of the present study was to investigate the enzymatic transformation of 35 OMPs under anaerobic conditions, which have been even less studied than aerobic systems. Initially, 13 OMPs were identified to be significantly biotransformed (>20%) by anaerobic sludge obtained from a full-scale anaerobic digester, predestining them as potential targets of anaerobic enzymes. Native enzymes were extracted from this anaerobic sludge to perform transformation assays with the OMPs. In addition, the effect of detergents to recover membrane enzymes, as well as the effects of cofactors and inhibitors to promote and suppress specific enzymatic activities were evaluated. In total, it was possible to recover enzymatic activities towards 10 out of these 13 target OMPs (acetyl-sulfamethoxazole and its transformation product sulfamethoxazole, acetaminophen, atenolol, clarithromycin, citalopram, climbazole, erythromycin, and terbutryn, venlafaxine) as well as towards 8 non-target OMPs (diclofenac, iopamidol, acyclovir, acesulfame, and 4 different hydroxylated metabolites of carbamazepine). Some enzymatic activities likely involved in the anaerobic biotransformation of these OMPs were identified. Thereby, this study is a starting point to unravel the still enigmatic biotransformation of OMPs in wastewater treatment systems. Graphical abstract: Image 1 Highlights: Understanding the biotransformation of micropollutants is key for their removal. 13 out of 35 micropollutants were significantly biotransformed by anaerobic sludge. Several micropollutants were transformed in a cell-free lysate of sludge enzymes. Some enzymes likely involved in the transformation of micropollutants were identified. The use of detergents, cofactors and inhibitors helps to identify responsible enzymes.