Exogenous Fe2+ alleviated the toxicity of CuO nanoparticles on Pseudomonas tolaasii Y-11 under different nitrogen sources

Yuran Yang; Can Zhang; Xuejiao Huang; Xuwei Gui; Yifang Luo; Zhenlun Li

doi:10.7717/peerj.10351

Exogenous Fe²⁺ alleviated the toxicity of CuO nanoparticles on Pseudomonas tolaasii Y-11 under different nitrogen sources

PeerJ. 2020 Nov 10:8:e10351. doi: 10.7717/peerj.10351. eCollection 2020.

Authors

Yuran Yang¹, Can Zhang¹, Xuejiao Huang¹, Xuwei Gui¹, Yifang Luo², Zhenlun Li¹

Affiliations

¹ Chongqing Key Laboratory of Soil Multi-Scale Interfacial Process, College of Resources and Environment, Southwest University, Chongqing, China.
² Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, China.

Abstract

Extensive use of CuO nanoparticles (CuO-NPs ) inevitably leads to their accumulation in wastewater and toxicity to microorganisms that effectively treat nitrogen pollution. Due to the effects of different mediums, the sources of CuO-NPs-induced toxicity to microorganisms and methods to mitigating the toxicity are still unclear. In this study, CuO-NPs were found to impact the nitrate reduction of Pseudomonas tolaasii Y-11 mainly through the action of NPs themselves while inhibiting the ammonium transformation of strain Y-11 through releasing Cu²⁺. As the content of CuO-NPs increased from 0 to 20 mg/L, the removal efficiency of NO₃ ^- and NH₄ ⁺ decreased from 42.29% and 29.83% to 2.05% and 2.33%, respectively. Exogenous Fe²⁺ significantly promoted the aggregation of CuO-NPs, reduced the possibility of contact with bacteria, and slowed down the damage of CuO-NPs to strain Y-11. When 0.01 mol/L Fe²⁺ was added to 0, 1, 5, 10 and 20 mg/L CuO-NPs treatment, the removal efficiencies of NO₃ ^- were 69.77%, 88.93%, 80.51%, 36.17% and 2.47%, respectively; the removal efficiencies of NH₄ ⁺ were 55.95%, 96.71%, 38.11%, 20.71% and 7.43%, respectively. This study provides a method for mitigating the toxicity of CuO-NPs on functional microorganisms.

Keywords: CuO-NPs; Detoxify; Ferrous ion; Functional microorganisms; Nitrogen removal.

Grants and funding

This work was supported by the National Key Research and Developmental Program of China (2017YFC0404705). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.