Abstract Diethyl phthalate (DEP) is a representative of phthalate esters (PAEs) that are largely used as industrial additives and have become environmental contaminants and endocrine disruptors. A newly isolated bacterial strain Sphingobium yanoikuyae SHJ was found to be capable of degrading DEP very efficiently. Four intermediates during the DEP degradation process were identified to be ethyl methyl phthalate (EMP), monoethyl phthalate (MEP), monomethyl phthalate (MMP) and phthalic acid (PA) using high-performance liquid chromatography tandem high-resolution mass spectrometry (HPLC-HRMS). When there was limited oxygen under SSA conditions, the rates of the further degradation of MEP and PA were slower compared to that under aerobic conditions. Although all intermediates EMP, MEP and MMP eventually decreased or disappeared, the DEP degradation kinetics showed that EMP formed much faster than that of MEP, and MMP appeared after the decreasing of MEP. It is proposed that two DEP degradation pathways must be present in S. yanoikuyae SHJ. The first is DEP → MEP → PA through a sequential hydrolysis process. The second is DEP → EMP → MEP → MMP → PA through a combination of demethylation or trans-esterification with methanol and hydrolysis processes. It is concluded that S. yanoikuyae SHJ has a versatile capability of degrading DEP and will have a great application potential in bioremediation of PAEs-contaminated shallow aquifer.

中文翻译：

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Sphingobium yanoikuyae SHJ生物降解邻苯二甲酸二乙酯的新途径

摘要 邻苯二甲酸二乙酯 (DEP) 是邻苯二甲酸酯 (PAE) 的代表，主要用作工业添加剂，已成为环境污染物和内分泌干扰物。发现一种新分离的细菌菌株 Sphingobium yanoikuyae SHJ 能够非常有效地降解 DEP。DEP 降解过程中的四种中间体被鉴定为邻苯二甲酸甲酯 (EMP)、邻苯二甲酸单乙酯 (MEP)、邻苯二甲酸单甲酯 (MMP) 和邻苯二甲酸 (PA) 使用高效液相色谱串联高分辨率质谱 (HPLC-人力资源管理系统）。当在 SSA 条件下氧气有限时，与有氧条件下相比，MEP 和 PA 的进一步降解速率更慢。尽管所有中间体 EMP、MEP 和 MMP 最终都减少或消失，DEP 降解动力学表明 EMP 的形成速度比 MEP 快得多，MMP 在 MEP 降低后出现。建议在 S. yanoikuyae SHJ 中必须存在两种 DEP 降解途径。第一个是通过顺序水解过程的 DEP → MEP → PA。第二种是 DEP → EMP → MEP → MMP → PA，通过去甲基化或酯交换与甲醇和水解过程的组合。得出的结论是，S. yanoikuyae SHJ 具有降解 DEP 的多功能能力，在 PAEs 污染的浅层含水层的生物修复中具有很大的应用潜力。第一个是通过顺序水解过程的 DEP → MEP → PA。第二种是 DEP → EMP → MEP → MMP → PA，通过去甲基化或酯交换与甲醇和水解过程的组合。得出的结论是，S. yanoikuyae SHJ 具有降解 DEP 的多功能能力，在 PAEs 污染的浅层含水层的生物修复中具有很大的应用潜力。第一个是通过顺序水解过程的 DEP → MEP → PA。第二种是 DEP → EMP → MEP → MMP → PA，通过去甲基化或酯交换与甲醇和水解过程的组合。得出的结论是，S. yanoikuyae SHJ 具有降解 DEP 的多功能能力，在 PAEs 污染的浅层含水层的生物修复中具有很大的应用潜力。