The promotion of iron redox cycle on anaerobic degradation of 3, 5, 6-trichloro-2-pyridinol in Pseudomonas aeruginosa D-2 by accelerating energy metabolism

• Published in: Journal of environmental chemical engineering Vol. 13; no. 3; p. 117041
• Main Authors: Lv, Xueru, Zhang, Lingping, Gao, Xijun, Zhang, Lele, Ding, Xiaoke, Wang, Xueting, Jia, Nan, Li, Wei, Li, Jie, Song, Caihong, Zhang, Chen, Wang, Shenghui
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2025
• Subjects: 3, 5, 6-trichloro-2-pyridinol; Anaerobic degradation; Iron ion redox cycle; Metabolic mechanisms; Pseudomonas aeruginosa; Anaerobic degradation; Metabolic mechanisms; Pseudomonas aeruginosa; Iron ion redox cycle; 3, 5, 6-trichloro-2-pyridinol
• ISSN: 2213-3437
• DOI: 10.1016/j.jece.2025.117041

The sluggish metabolism of 3,5,6-trichloro-2-pyridinol (TCP) in anoxic or anaerobic environments poses a significant bioremediation challenge. Herein, the soluble Fe(II) was firstly incorporated into the anaerobic biodegradation of TCP by Pseudomonas aeruginosa D-2 and the biochemical role of iron ions in enhancing TCP metabolism were investigated. The Fe(II) ion significantly enhanced the anaerobic biodegradation of TCP (50 mg/L) with the removal efficiency increasing from 50.24 % to 80.32 % within 72 h, along with noticeable cellular proliferation. Interestingly, this process was accompanied by a dynamic equilibrium transformation between Fe(II) and Fe(III). Further study revealed TCP's dechlorination metabolite was substantially degraded by strain D-2 concurrently with the reduction of Fe(III) to Fe(II), suggesting the iron ions redox cycle significantly promoted the anaerobic biodegradation of TCP. Moreover, metabolomics analysis conformed strain D-2 could perform anaerobic reductive dechlorination of TCP. More importantly, genomic and transcriptomic analyses firstly revealed Fe(II) markedly enriched energy metabolism pathways, such as TCA cycle and oxidative phosphorylation, and obviously up-regulated some iron-dependent enzymes crucial for ring-cleaving and energy metabolism. These up-regulation may provide ATP and reducing power for the cell growth and the initiation of reductive dechlorination of TCP. This study would facilitate the development of effective biological or chemical remediation techniques to promote the anaerobic biodegradation of halogenated aromatic contaminants. •Fe(II) enhanced the anaerobic degradation of TCP by P. aeruginosa D-2, along with noticeable cellular proliferation.•This process was accompanied by a dynamic equilibrium transformation between Fe(II) and Fe(III).•Fe(II) enriched the energy metabolism pathways and up-regulated some iron-dependent enzymes.•The iron ions redox cycle may act as an 'energy buffer,' promoting the anaerobic biodegradation of TCP.