Combatting multiple aromatic organohalide pollutants in sediments by bioaugmentation with a single Dehalococcoides

Guofang Xu; Hung Liang Ng; Chen Chen; Matthew J Rogers; Jianzhong He

doi:10.1016/j.watres.2024.121447

Combatting multiple aromatic organohalide pollutants in sediments by bioaugmentation with a single Dehalococcoides

Water Res. 2024 May 15:255:121447. doi: 10.1016/j.watres.2024.121447. Epub 2024 Mar 11.

Authors

Guofang Xu¹, Hung Liang Ng¹, Chen Chen¹, Matthew J Rogers¹, Jianzhong He²

Affiliations

¹ Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576.
² Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576. Electronic address: jianzhong.he@nus.edu.sg.

PMID: 38508042
DOI: 10.1016/j.watres.2024.121447

Abstract

Dehalococcoides are capable of dehalogenating various organohalide pollutants under anaerobic conditions, and they have been applied in bioremediation. However, the presence of multiple aromatic organohalides, including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and tetrabromobisphenol A (TBBPA), at contaminated sites may pose challenges to Dehalococcoides-mediated bioremediation due to the lack of knowledge about the influence of co-contamination on bioremediation. In this study, we investigated the bioremediation of aromatic organohalides present as individual and co-contaminants in sediments by bioaugmentation with a single population of Dehalococcoides. Bioaugmentation with Dehalococcoides significantly increased the dehalogenation rate of PCBs, PBDEs, and TBBPA in sediments contaminated with individual pollutants, being up to 19.7, 27.4 and 2.1 times as that in the controls not receiving bioinoculants. For sediments containing all the three classes of pollutants, bioaugmentation with Dehalococcoides also effectively enhanced dehalogenation, and the extent of enhancement depended on the bioinoculants and types of pollutants. Interestingly, in many cases co-contaminated sediments bioaugmented with Dehalococcoides mccartyi strain CG1 displayed a greater enhancement in dehalogenation rates compared to the sediments polluted with individual pollutant. For instance, when augmented with a low quantity of strain CG1, the dehalogenation rates of Aroclor1260 and PBDEs in co-contaminated sediments were approximately two times as that in sediments containing individual pollutants (0.428 and 9.03 vs. 0.195 and 4.20 × 10^-3d^-1). Additionally, D. mccartyi CG1 grew to higher abundances in co-contaminated sediments. These findings demonstrate that a single Dehalococcoides population can sustain dehalogenation of multiple aromatic organohalides in contaminated sediments, suggesting that co-contamination does not necessarily impede the use of Dehalococcoides for bioremediation. The study also underscores the significance of anaerobic organohalide respiration for effective bioremediation.

Keywords: Aromatic organohalide pollutants; Bioremediation; Co-contamination; Dehalococcoides; Microbiome; Multifunctional reductive dehalogenase.