CO₃²⁻ enhanced electron transfer and enzyme stabilization overcome the ion inhibition paradigm in aerobic denitrification

i

This article has been updated. A Correction to this article was published on .

i

The Original Article was published on

i

The Original Article was published on

i

This article has been updated

i

This article was retracted on

i

This article has been updated

Abstract

Aerobic denitrifying bacteria are often inhibited by inorganic ions during wastewater treatment, and elucidating their regulatory mechanisms is crucial for enhancing nitrogen removal efficiency. In this study, we systematically investigated the effects of varying concentrations of inorganic ions (0–200 mg/L) on the growth, denitrification performance, and metabolic activity of Pseudomonas mosselii H6. Based on enzyme kinetics, energy metabolism indicators, and measurements of electron transport chain activity, CO₃²⁻ was found to significantly enhance denitrification capacity. At 200 mg/L, electron transport system activity (ETSA) increased by 26.42%, ATP synthesis peaked at 1.25 μmol/mg prot, and the NADH/NAD⁺ ratio rose to 22.69. Nitrate reductase (NR) and nitrite reductase (NiR) activities reached 28.37 and 17.76 U/mg prot, respectively. In contrast, Cl⁻ and NO₃⁻ at 200 mg/L markedly suppressed cellular metabolism, reducing NH₄⁺-N removal efficiency to 21.41% and 16.42%, respectively. These findings revealed a concentration-dependent and ion-specific regulatory mechanism. CO₃²⁻ enhances nitrogen removal by optimizing electron transfer and improving enzyme stability. This study provides a theoretical foundation for optimizing the biological treatment of high-salinity wastewater.

Keywords

aerobic denitrification / Pseudomonas mosselii H6 / CO₃²⁻ / electron transport / enzyme stability

CHANGE HISTORY

A Correction to this paper has been published:
https://doi.org

The Retraction Note was updated to reflect reception of statements of disagreement from all authors.

This article has been retracted.Please see the Retraction Notice for more detail:
https://doi.org

References

[1] Li X, Jin Y X, He YY, et al. (2025) Mechanisms of N₂O production in salinity-adapted partial nitritation systems for high-ammonia wastewater treatment . Water Res X 27: 100311. https://doi.org/10.1016/J.WROA.2025.100311

[2] Wei R, Hui C, Zhang YP, et al. (2020) Nitrogen removal characteristics and predicted conversion pathways of a heterotrophic nitrification-aerobic denitrification bacterium, Pseudomonas aeruginosa P-1. Environ Sci Pollut R 28: 7503-7514. https://doi.org/10.1007/s11356-020-11066-7

[3] Chen JL, Xu J, Zhang SN, et al. (2021) Nitrogen removal characteristics of a novel heterotrophic nitrification and aerobic denitrification bacteria, Alcaligenes faecalis strain WT14. J Environ Manag 282: 111961. https://doi.org/10.1016/J.JENVMAN.2021.111961

[4] Song T, Zhang XL, Li J, et al. (2021) A review of research progress of heterotrophic nitrification and aerobic denitrification microorganisms (HNADMs). Sci Total Environ 801: 149319. https://doi.org/10.1016/J.SCITOTENV.2021.149319

[5] Huang MQ, Cui YW, Huang JL, et al. (2022) A novel Pseudomonas aeruginosa strain performs simultaneous heterotrophic nitrification-aerobic denitrification and aerobic phosphate removal. Water Res 221: 118823. https://doi.org/10.1016/J.WATRES.2022.118823

[6] Xi HP, Zhou XT, Arslan M, et al. (2022) Heterotrophic nitrification and aerobic denitrification process: Promising but a long way to go in the wastewater treatment. Sci Total Environ 805: 150212. https://doi.org/10.1016/J.SCITOTENV.2021.150212

[7] Hou M, Li W, Li H, et al. (2019) Performance and bacterial characteristics of aerobic granular sludge in response to alternating salinity. Int Biodeter Biodegr 142: 211-217. https://doi.org/10.1016/j.ibiod.2019.05.007

[8] Chen AL, Su X, Xing ZL, et al. (2022) Effect mechanism of individual and combined salinity on the nitrogen removal yield of heterotrophic nitrification-aerobic denitrification bacteria. Environ Res 214: 113834. https://doi.org/10.1016/J.ENVRES.2022.113834

[9] Ma TF, Ma HX, Xing CY, et al. (2025) Physiological and proteomic insights into silver nanoparticle-induced stress responses and resistance mechanisms in aerobic denitrifying Enterobacter cloacae HNR. J Environ Chem Eng 13: 115934. https://doi.org/10.1016/J.JECE.2025.115934

[10] Yin C, Li Y, Zhang TY, et al. (2020) Effects of exposure to anionic surfactants (SDBS and SDS) on nitrogen removal of aerobic denitrifier. Water Environ Res 92: 2129-2139. https://doi.org/10.1002/wer.1384

[11] Shi CY, Gou F, Chen LA, et al. (2024) Influence and mechanism of typical transition metal ions on the denitrification performance of heterotrophic nitrification-aerobic denitrification bacteria. Environ Res 258: 119460. https://doi.org/10.1016/J.ENVRES.2024.119460

[12] Fang JK, Liao SA, Zhang SS, et al. (2021) Characteristics of a novel heterotrophic nitrification-aerobic denitrification yeast, Barnettozyma californica K1. Bioresource Technol 339: 125665. https://doi.org/10.1016/J.BIORTECH.2021.125665

[13] Wu GY, Yang GF, Sun XR, et al. (2023) Simultaneous denitrification and organics removal by denitrifying bacteria inoculum in a multistage biofilm process for treating desulfuration and denitration wastewater. Bioresource Technol 388: 129757. https://doi.org/10.1016/J.BIORTECH.2023.129757

[14] Gao J, Duan XD, O’Shea K, et al. (2019) Degradation and transformation of bisphenol A in UV/Sodium percarbonate: Dual role of carbonate radical anion. Water Res 171: 115394. https://doi.org/10.1016/j.watres.2019.115394

[15] Keykha HA, Zangani A, Romiani HM, et al. (2023) Characterizing microbial and CO₂-induced carbonate minerals: Implications for soil stabilization in sandy environments. Minerals 13: 976. https://doi.org/10.3390/MIN13070976

[16] Shi LD, Gao TY, Wei XW, et al. (2022) pH-dependent hydrogenotrophic denitratation based on self-alkalization. Environ Sci Technol 57: 685-696. https://doi.org/10.1021/ACS.EST.2C05559

[17] Fernández AR, Areias C, Daffonchio D, et al. (2022) The role of microorganisms in the nucleation of crbonates, environmental implications and applications. Minerals 12: 1562. https://doi.org/10.3390/MIN12121562

[18] Yue X, You A, Liu Y, et al. (2023) Low-concentration methanol effect on the microorganisms, nitrogen removal, and recovery of the completely autotrophic nitrogen removal over nitrite. Water Sci Technol 87: 130-143. https://doi.org/10.2166/WST.2022.417

[19] Hu T, Wei JT, Ding YH, et al. (2024) Characterisation of Pseudomonas mosselii H6 for aerobic denitrification: Stoichiometry and reaction kinetics. Biotechnol Biotec Eq 38. https://doi.org/10.1080/13102818.2024.2402445

[20] Zhang Y, Bao JG, Du JK, et al. (2023) Comprehensive metagenomic and enzyme activity analysis reveals the inhibitory effects and potential toxic mechanism of tetracycline on denitrification in groundwater. Water Res 247: 120803. https://doi.org/10.1016/J.WATRES.2023.120803

[21] Chen JH, Xue Y, Yang DL, et al. (2023) Optimizing waste molasses utilization to enhance electron transfer via micromagnetic carriers: Mechanisms and high-nitrate wastewater denitrification performance. Environ Res 242: 117709. https://doi.org/10.1016/J.ENVRES.2023.117709

[22] Yang G, Luo YD, Bian YH, et al. (2024) Electro-mediated cathodic oxygen drives respiration chain electron transfer of electroactive bacteria to enhance refractory organic biological oxidation. Water Res 268: 122585. https://doi.org/10.1016/J.WATRES.2024.122585

[23] Feng J, Shaik SS, Wang BJ (2021) Spin-regulated electron transfer and exchange-enhanced reactivity in Fe₄S₄-mediated redox reaction of the Dph₂ enzyme during the biosynthesis of Diphthamide . Angew Chem Int Edit 60: 20430-20436. https://doi.org/10.1002/anie.202107008

[24] Huang JE, Li FW, Ozden A, et al. (2021) CO₂ electrolysis to multicarbon products in strong acid. Science 372: 1074-1078. https://doi.org/10.1126/SCIENCE.ABG6582

[25] Zhang ZS, Gao PT, Guo L, et al. (2020) Elucidating temperature on mixotrophic cultivation of a Chlorella vulgaris strain: Different carbon source application and enzyme activity revelation. Bioresource Technol 314: 123721. https://doi.org/10.1016/j.biortech.2020.123721

[26] Marcandalli G, Boterman K, Koper M (2022) Understanding hydrogen evolution reaction in bicarbonate buffer. J Catal 405: 346-354. https://doi.org/10.1016/J.JCAT.2021.12.012

[27] Lan QF, Yang YM, Xie ZY, et al. (2023) Molecular dynamics calculation of the coordination behavior of Yb (III) in Sodium Carbonate solution. Processes 11: 2624. https://doi.org/10.3390/PR11092624

[28] Jentsch TJ, Pusch M (2018) CLC Chloride channels and transporters: Structure, function, physiology, and disease. Physiol Rev 98: 1493-1590. https://doi.org/10.1152/physrev.00047.2017

[29] Yoshinori M (2023) Physiological roles of chloride ions in bodily and cellular function. J Physiol Sci 73: 31. https://doi.org/10.1186/S12576-023-00889-X

[30] Wang H, Lu HG, Xu L, et al. (2021) Molybdate transporter ModABC contributes to Klebsiella pneumoniae muscle infection and new insight into its treatment. Microbiology 48: 2784-2800. https://doi.org/10.13344/j.microbiol.china.201103

[31] Peters K, Staehlke S, Rebl H, et al. (2024) Impact of metal ions on Cellular functions: A focus on mesenchymal stem/stromal cell differentiation. Int J Mol Sci 25: 10127. https://doi.org/10.3390/IJMS251810127