Size dependent impacts of a model microplastic on nitrification induced by interaction with nitrifying bacteria

Jongkeun Lee; Seulki Jeong; Chenghua Long; Kartik Chandran

doi:10.1016/j.jhazmat.2021.127363

Size dependent impacts of a model microplastic on nitrification induced by interaction with nitrifying bacteria

J Hazard Mater. 2022 Feb 15;424(Pt B):127363. doi: 10.1016/j.jhazmat.2021.127363. Epub 2021 Sep 28.

Authors

Jongkeun Lee¹, Seulki Jeong², Chenghua Long³, Kartik Chandran⁴

Affiliations

¹ Department of Earth and Environmental Engineering, Columbia University in the City of New York, 500 West 120th Street, New York, NY 10027, USA; Department of Civil and Environmental Engineering, College of Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, South Korea.
² Department of Earth and Environmental Engineering, Columbia University in the City of New York, 500 West 120th Street, New York, NY 10027, USA; Seoul center, Korea Basic Science Institute, 6-7, Inchon-ro 22-gil, Seongbuk-gu, Seoul 02855, South Korea. Electronic address: sjeong85@kbsi.re.kr.
³ Department of Earth and Environmental Engineering, Columbia University in the City of New York, 500 West 120th Street, New York, NY 10027, USA.
⁴ Department of Earth and Environmental Engineering, Columbia University in the City of New York, 500 West 120th Street, New York, NY 10027, USA. Electronic address: kc2288@columbia.edu.

PMID: 34634706
DOI: 10.1016/j.jhazmat.2021.127363

Abstract

Two sizes of polystyrene (PS) were compared to investigate their impact on nitrification. The smaller PS (50 nm) had a higher impact than the larger PS (500 nm). Lower NO₂^- and NO₃^- accumulation was observed in the 50 nm PS treatment. There was no significant difference in DIN concentration between the control and 500 nm PS treatments. PS treatment did not have a significant influence on the specific ammonia oxidation rate, but the specific nitrite utilization rate was the lowest in the 50 nm PS treatment. The changes in transcript levels of amoA gene did not correspond well with the observed changes in DIN concentrations, suggesting that the effects of 50 nm PS treatment might be unrelated to biological phenomena, for which an actual uptake of PS is needed. The fluorescent images revealed that the smaller PS can easily access bacterial cells, which corroborated the results of inhibition of nitrification by the smaller PS. Notably, most of the PS particles did not penetrate bacterial cells, suggesting that the observed effects of 50 nm PS on nitrification might be due to disruption of the membrane potential of the cells.

Keywords: Microplastic; Nitrification; Nitrifying bacteria; Polystyrene; amoA expression.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Ammonia
Bacteria / genetics
Microplastics*
Nitrification*
Oxidation-Reduction
Plastics

Substances

Microplastics
Plastics
Ammonia