Efficient biostimulation of microbial dechlorination of polychlorinated biphenyls by acetate and lactate under nitrate reducing conditions: Insights into dechlorination pathways and functional genes.

Autor: Xu Y; Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu 210096, China. Electronic address: xuxucalmm@seu.edu.cn., Wang Y; Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu 210096, China., Zheng A; Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu 210096, China., Yuan Y; Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu 210096, China., Xu L; Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu 210096, China., Tang Y; Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu 210096, China., Qin Q; Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu 210096, China.
Jazyk: angličtina
Zdroj: Journal of hazardous materials [J Hazard Mater] 2024 Apr 15; Vol. 468, pp. 133775. Date of Electronic Publication: 2024 Feb 11.
DOI: 10.1016/j.jhazmat.2024.133775
Abstrakt: Microbial-catalyzed reductive dechlorination of polychlorinated biphenyls (PCBs) is largely affected by the indigenous sediment geochemical properties. In this study, the effects of nitrate on PCB dechlorination and microbial community structures were first investigated in Taihu Lake sediment microcosms. And biostimulation study was attempted supplementing acetate/lactate. PCB dechlorination was apparently inhibited under nitrate-reducing conditions. Lower PCB dechlorination rate and less PCB dechlorination extent were observed in nitrate amended sediment microcosms (T-N) than those in non-nitrate amended microcosms (T-1) during 66 weeks of incubation. The total PCB mass reduction in T-N was 17.6% lower than that in T-1. The flanked-para dechlorination was completely inhibited, while the ortho-flanked meta dechlorination was only partially inhibited in T-N. The 7.5 mM of acetate/lactate supplementation recovered PCB dechlorination by resuming ortho-flanked meta dechlorination. Repeated additions of lactate showed more effective biostimulation than acetate. Phylum Chloroflexi, containing most known PCB dechlorinators, was found to play a vital role on stability of the network structures. In T-N, putative dechlorinating Chloroflexi, Dehalococcoides and RDase genes rdh12, pcbA4, pcbA5 all declined. With acetate/lactate supplementation, Dehalococcoides grew by 1-2 orders of magnitude and rdh12, pcbA4, pcbA5 increased by 1-3 orders of magnitude. At Week 66, parent PCBs declined by 86.4% and 80.9% respectively in T-N-LA and T-N-AC compared to 69.9% in T-N. These findings provide insights into acetate/lactate biostimulation as a cost-effective approach for treating PCB contaminated sediments undergoing nitrate inhibition.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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