Evidences of extracellular abiotic degradation of hexadecane through free radical mechanism induced by the secreted phenazine compounds of P. aeruginosa NY3. (1st August 2018)

• Record Type: Journal Article
• Authors: Nie, Hongyun; Nie, Maiqian; Wang, Lei; Diwu, Zhenjun; Xiao, Ting; Qiao, Qi; Wang, Yan; Jiang, Xin
• Is Part Of: Water research. Volume 139(2018)
• Page Start: 434
• Page End: 441
• Publication Date: 2018-08-01
• Subjects: P. aeruginosa NY3 -- Hexadecane -- Phenazine compounds -- Degradation -- Free radical; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2018.02.053
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: The aim of this work was to investigate the effects of secreted extracellular phenazine compounds (PHCs) on the degradation efficiency of alkanes by P. aeruginosa NY3. Under aerobic conditions, the PHCs secreted by P. aeruginosa NY3 initiate the oxidation of alkanes outside cells, in coupling with some reducing agents, such as β-Nicotinamide adenine dinucleotide, reduced disodium salt (NADH) or reduced glutathione (GSH). This reaction might be via free radical reactions similar to Fenton Oxidation Reaction (FOR). P. aeruginosa NY3 secretes pyocyanin (Pyo), 1-hydroxyphenazine (HPE), phenazine-1-carboxylic acid (PCA), and phenazine-1-amide (PCN) simultaneously. The cell-free extracellular fluid containing these four PHCs degrades hexadecane effectively. The observation of Electron Spin Resonance (EPR) signals of superoxide anion radical ( O2 − ), hydroxyl radical (OH) and/or carbon free radicals (R) both in vivo and in vitro suggested the degradation of hexadecane could be via a free radical pathway. Secretion of PHCs has been found to be characteristic of Pseudomonas which is often involved in or related to the degradation of organic pollutants. Our work suggested that certain organic contaminants may be oxidized through ubiquitously extracellular abiotic degradation by the free radicals produced during bio-remediation and bio-treatment. Graphical abstract: Highlights: Strain NY3 could simultaneously secrete Pyo, HPE, PCA and PCN during growing on alkanes. Reactions of PHCs with NADH or GSH could degrade alkanes by free radical pathways. Degradation of alkanes by extracellular PHCs and NADH or GSH existed in culture medium of strain NY3.