Trichloroethylene (TCE) is a carcinogenic organic chemical impacting water resources worldwide. Its breakdown by reductive vs oxidative degradation involves different types of chemical bonds. Hence, if distinct isotope effects are reflected in dual element (carbon and chlorine) isotope values, such trends could help distinguishing both processes in the environment. This work explored dual element isotope trends associated with TCE oxidation by two pure bacterial cultures: Pseudomonas putida F1 and Methylosinus trichosporium OB3b, where the latter expresses either soluble methane-monooxygenase (sMMO) or particulate methane-monooxygenase (pMMO). Carbon and chlorine isotope enrichment factors of TCE (ε¹³C = −11.5, −2.4, and −4.2‰; ε³⁷Cl = 0.3, −1.3, and −2.4‰, respectively) differed strongly between the strains. The dual element isotope trend for strain F1 (ε¹³C/ε³⁷Cl = −38) reflected, as expected, primary carbon and negligible chlorine isotope effects, whereas unexpectedly large chlorine isotope effects became apparent in the trend obtained with strain OB3b (ε¹³C/ε³⁷Cl = +1.7 for sMMO and pMMO). Therefore, although dual element isotope analysis partly reflects predicted differences in oxidative vs reductive (ε¹³C/ε³⁷Cl = 3.4–5.7) degradation, the unexpected OB3b fractionation data may challenge field interpretation.

中文翻译：

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δ ¹³ C和δ ³⁷三氯乙烯的氯同位素分馏表征有氧VS厌氧降解

三氯乙烯（TCE）是影响全球水资源的致癌有机化学物质。其通过还原降解与氧化降解的分解涉及不同类型的化学键。因此，如果在双元素（碳和氯）同位素值中反映出独特的同位素效应，则这种趋势将有助于区分环境中的两个过程。这项工作探索了两种纯细菌培养物与三氯乙烯（TCE）氧化相关的双元素同位素趋势：恶臭假单胞菌F1和甲基毛状孢霉OB3b，后者表达可溶性甲烷单加氧酶（sMMO）或颗粒甲烷单加氧酶（pMMO）。TCE的碳和氯的同位素富集因子（ε ¹³ C = -11.5，-2.4，-4.2和‰;ε ³⁷Cl分别为0.3，-1.3和-2.4‰）。双元件同位素趋势应变F1（ε ¹³ C /ε ³⁷ CL = -38）反射，如预期的，伯碳和可忽略的氯同位素影响，而出乎意料的大的氯的同位素效应与应变OB3b获得的趋势变得明显（ε ¹³ C /ε ³⁷ CL = 1.7为单加氧酶和单加氧酶）。因此，尽管双元件同位素分析部分反映在氧化还原VS预测的差异（ε ¹³ C /ε ³⁷ CL = 3.4-5.7）降解，意想不到OB3b分馏数据可能挑战字段解释。