标题: Biodegradation of phthalic acid esters (PAEs) by Cupriavidus oxalaticus strain E3 isolated from sediment and characterization of monoester hydrolases
作者: Chen, FY (Chen, Fangyuan); Li, XL (Li, Xuli); Dong, YQ (Dong, Yiqie); Li, JH (Li, Jiahao); Li, YX (Li, Yixin); Li, H (Li, He); Chen, L (Chen, Lei); Zhou, M (Zhou, Min); Hou, HB (Hou, Haobo)
来源出版物: CHEMOSPHERE 卷: 266 文献号: 129061 DOI: 10.1016/j.chemosphere.2020.129061 出版年: MAR 2021
摘要: Phthalic acid esters (PAEs) are teratogenic and carcinogenic and mainly metabolized by microorganisms in sediment. A novel strain, Cupriavidus oxalaticus strain E3, was isolated and characterized from sediment for PAEs degradation. The transformation of dibutyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP) as the sole carbon source by strain E3 was systematically studied in the darkness through the kinetic studies and analysis of intermediates. After the initial lag pause of 5 he8 h, the strain efficiently degraded 87.4%-94.4% of DBP and 82.5%-85.6% of DEHP at an initial amount of each phthalate of 200 mg/L after 60 h of incubation. The biodegradation rate of DBP and DEHP followed a first-order kinetic model, and degradation rate constants (k) of them by E3 were 1.37 and 0.86 d(-)1, respectively. Gas chromatography-mass spectrometry (GC-MS) results revealed that the tentative PAEs degradation pathway, included the transformation from PAEs to phthalic acid (PA) and the complete mineralization of PA. In the phase of PAEs to PA, DBP with short sides reduced the chain length via hydrolyzation, and DEHP with long sides reduced the chain length via hydrolyzation and beta-oxidation. The 3D model of monoester hydrolase from C. oxalaticus was predicted and used for docking with mono-2-ethylhexyl phthalate (MEHP) and mono-n-butyl phthalate (MBP). The docking results showed that the conserved catalytic triplet structure (Ser140, His284, and Asp254) acted as active sites and participated in degrading PMEs. This study provided novel insights into the mechanisms of PAEs degradation at a molecular level and widened the scope of functional bacteria by isolating strain E3. (C) 2020 Elsevier Ltd. All rights reserved.
PubMed ID: 33310526
作者关键词: Plasticizers; Transformation pathway; Genome sequencing; Catalytic triplet
地址: [Chen, Fangyuan; Li, Xuli; Dong, Yiqie; Li, Jiahao; Li, Yixin; Li, He; Chen, Lei; Zhou, Min; Hou, Haobo] Wuhan Univ, Sch Resource & Environm Sci, Wuhan 430079, Hubei, Peoples R China.
[Hou, Haobo] Zhaoqing Wuhan Univ, Environm Technol Res Inst, Zhaoqing 526200, Guangdong, Peoples R China.
通讯作者地址: Hou, HB (通讯作者)，Zhaoqing Wuhan Univ, Environm Technol Res Inst, Zhaoqing 526200, Guangdong, Peoples R China.
Zhou, M; Hou, HB (通讯作者)，Wuhan Univ, Sch Resource & Environm Sci, Dept Environm Engn, Wuhan 430079, Hubei, Peoples R China.
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