Biotransformation of Sulfluramid (N-ethyl perfluorooctane sulfonamide) and dynamics of associated rhizospheric microbial community in microcosms of wetland plants

Tingru Yin; Shu Harn Te; Martin Reinhard; Yi Yang; Huiting Chen; Yiliang He; Karina Yew-Hoong Gin

doi:10.1016/j.chemosphere.2018.07.157

Biotransformation of Sulfluramid (N-ethyl perfluorooctane sulfonamide) and dynamics of associated rhizospheric microbial community in microcosms of wetland plants

Chemosphere. 2018 Nov:211:379-389. doi: 10.1016/j.chemosphere.2018.07.157. Epub 2018 Jul 27.

Authors

Tingru Yin¹, Shu Harn Te², Martin Reinhard³, Yi Yang², Huiting Chen², Yiliang He⁴, Karina Yew-Hoong Gin⁵

Affiliations

¹ Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore.
² NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, T-Lab Building, Singapore 117411, Singapore.
³ NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, T-Lab Building, Singapore 117411, Singapore; Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305, USA.
⁴ School of Environmental Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: ylhe@sjtu.edu.cn.
⁵ Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore; NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, T-Lab Building, Singapore 117411, Singapore. Electronic address: ceeginyh@nus.edu.sg.

PMID: 30077934
DOI: 10.1016/j.chemosphere.2018.07.157

Abstract

Although the use of Sulfluramid (N-ethyl perfluorooctane sulfonamide (N-EtFOSA)) has been restricted by the Stockholm Convention, it is still frequently detected in the environmental matrices and in use in some countries. Employing constructed wetlands as treatment systems requires understanding of the biodegradation process in the rhizosphere and the effect of contaminants on the microbes of wetlands. This study aimed to investigate the interactions between the microbial community and N-EtFOSA under aerobic and anaerobic conditions. Aerobic biotransformation of N-EtFOSA occurred with a half-life of 0.51 day and yielded 85.1 mol% PFOS of after 91 days. Kinetic modelling revealed that cleavage of the SN was the rate-limiting degradation step. Biotransformation was not observed under anaerobic and anoxic conditions, suggesting that N-EtFOSA is recalcitrant to biodegradation without dissolved oxygen. Under aerobic condition, the presence of N-EtFOSA and its biotransformation products decreased the microbial richness and diversity and exerted selective pressure on the microbial community. Enrichment of Methylocaldum was significant (49%) in the presence of N-EtFOSA compared to unexposed conditions (11%), suggesting that Methylocaldum is relatively tolerant to N-EtFOSA and potentially degrading N-EtFOSA. Under anaerobic conditions, the microbial richness and diversity were not significantly altered by the presence of N-EtFOSA. Only Methanomethylovorans increased significantly in the spiked microcosm (30% vs. 20%). These findings provide knowledge for comprehending the contribution of N-EtFOSA to other PFASs in various environmental conditions, information about microbial community changes in response to PFASs and robust microbial species which can degrade N-EtFOSA in the environment.

Keywords: Anaerobic conditions; Biotransformation; Methylocaldum; Microbial community; Sulfluramid.

MeSH terms

Biodegradation, Environmental / drug effects*
Biotransformation / genetics*
Fluorocarbons / chemistry*
Rhizosphere*
Sulfonamides / chemistry*
Wetlands*

Substances

Fluorocarbons
Sulfonamides
perfluorooctane
sulfluramid