Wei Xi, Gilevska Tetyana, Wetzig Felix, Dorer Conrad, Richnow Hans-Hermann, Vogt Carsten
Helmholtz Centre for Environmental Research - UFZ, Department of Isotope Biogeochemistry, Leipzig, Germany; Friedrich Schiller University Jena, Institute for Microbiology, Department of Applied and Ecological Microbiology, Jena, Germany.
Helmholtz Centre for Environmental Research - UFZ, Department of Isotope Biogeochemistry, Leipzig, Germany.
Environ Pollut. 2016 Mar;210:166-73. doi: 10.1016/j.envpol.2015.11.005. Epub 2015 Dec 21.
Microbial degradation of phenol and cresols can occur under oxic and anoxic conditions by different degradation pathways. One recent technique to take insight into reaction mechanisms is compound-specific isotope analysis (CSIA). While enzymes and reaction mechanisms of several degradation pathways have been characterized in (bio)chemical studies, associated isotope fractionation patterns have been rarely reported, possibly due to constraints in current analytical methods. In this study, carbon enrichment factors and apparent kinetic isotope effects (AKIEc) of the initial steps of different aerobic and anaerobic phenol and cresols degradation pathways were analyzed by isotope ratio mass spectrometry connected with liquid chromatography (LC-IRMS). Significant isotope fractionation was detected for aerobic ring hydroxylation, anoxic side chain hydroxylation, and anoxic fumarate addition, while anoxic carboxylation reactions produced small and inconsistent fractionation. The results suggest that several microbial degradation pathways of phenol and cresols are detectable in the environment by CSIA.
苯酚和甲酚的微生物降解可通过不同的降解途径在有氧和无氧条件下发生。一种用于深入了解反应机制的最新技术是化合物特异性同位素分析（CSIA）。虽然几种降解途径的酶和反应机制已在（生物）化学研究中得到表征，但相关的同位素分馏模式却鲜有报道，这可能是由于当前分析方法的限制所致。在本研究中，通过与液相色谱联用的同位素比率质谱法（LC-IRMS）分析了不同好氧和厌氧苯酚及甲酚降解途径初始步骤的碳富集因子和表观动力学同位素效应（AKIEc）。在好氧环羟基化、无氧侧链羟基化和无氧富马酸酯加成过程中检测到显著的同位素分馏，而无氧羧化反应产生的分馏较小且不一致。结果表明，通过CSIA可在环境中检测到苯酚和甲酚的几种微生物降解途径。
