| 高曦,陈美骅,孙凯.腐植酸对漆酶诱导雌激素自聚合动力学的影响[J].农业环境科学学报,2023,42(5):1042-1050. |
| 腐植酸对漆酶诱导雌激素自聚合动力学的影响 |
| Laccase-induced self-polymerization of estrogens: effect of humic acid on transformation kinetics |
| 投稿时间：2022-09-22 |
| DOI：10.11654/jaes.2022-0876 |
| 中文关键词: 腐植酸 真菌漆酶 雌激素 聚合反应 影响机制 |
| 英文关键词: humic acid fungal laccase estrogen polyreaction influencing mechanism |
| 基金项目:国家自然科学基金项目（42277019，41907314）；安徽省高等学校自然科学研究项目（KJ2021A0136） |
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| 中文摘要: |
| 本文选择17β-雌二醇（E2）、17α-炔雌醇（EE2）和双酚A（BPA）作为环境中3种典型的代表性雌激素，采用批量平衡试验方法，研究了腐植酸（HA）对变色栓菌（Trametes versicolor）漆酶诱导雌激素转化动力学、产物分布和作用机制的影响。结果表明：漆酶在3 h内对3种雌激素的去除率均高于95%，E2、EE2和BPA的转化动力学常数（k）分别为2.48、2.03 h-1和1.45 h-1。添加HA有效抑制了E2 （k=1.04 h-1）和EE2 （k=0.64 h-1）的转化，但促进了BPA的去除（k=3.13 h-1），漆酶诱导HA和长链BPA自聚物发生共聚合反应，所形成的BPA-HA共聚物快速降低了长链BPA自聚物的产量，从而消除了其对漆酶催化活性和稳定性的抑制作用。产物鉴定证实了雌激素的转化产物主要为二聚体、三聚体和四聚体等低聚物。雌激素和HA的共聚合机制分为2个步骤：首先，雌激素和HA被漆酶单电子氧化，该过程形成大量的活性自由基中间体；随后，这些不稳定的活性自由基中间体通过C-C、C-O-C或C-N-C键共价结合，生成多种结构复杂的雌激素自聚物和共聚物。研究表明，HA能够影响漆酶诱导雌激素自聚合，形成更加复杂的共聚合产物，从而消除环境雌激素污染、封存有机碳。 |
| 英文摘要: |
| Laccase is capable of catalyzing the one-electron oxidation of estrogens to produce macromolecular polymers, using dissolved O2 in water as the final electron acceptor. Presently, little information is available regarding the effects of humic acid(HA) on laccaseinduced estrogen self-polymerization. In this study, we selected 17β-estradiol(E2), 17α-ethinylestradiol(EE2), and bisphenol A(BPA) as three representative environmental estrogens. The effects of HA on the laccase-induced estrogen transformation kinetics, product distribution, and mechanisms were all systematically investigated. The results of this indicated that the removal efficiencies of the three estrogens by laccase were greater than 95% within 3 h, and that the transformation kinetic constants(k) of E2, EE2, and BPA were 2.48, 2.03 h-1, and 1.45 h-1, respectively. HA effectively inhibited laccase-started E2(k=1.04 h-1) and EE2 conversion(k=0.64 h-1), whilst promoting the removal of BPA(k=3.13 h-1). This was likely because laccase-induced HA and BPA co-polymerization rapidly reduced the yields of long-chain BPA self-polymers, thus eliminating their inhibition of catalytic activity and the stability of laccase. Product identification confirmed that the transformation products of the three estrogens were mainly dimers, trimers, tetramers, and oligomers. The co-polymerization mechanisms of estrogen and HA involved two steps here:Firstly, estrogen and HA were oxidized by laccase, which formed many active free radical intermediates. Subsequently, these unstable radical intermediates were covalently bound by C-C, C-O-C, or C-N-C bonds to generate estrogenic self/co-polymeric products. These findings uncover the co-polymerization mechanisms of estrogen-HA induced by laccase and provide a theoretical basis for eliminating estrogen contamination and sequestrating organic carbon based on enzymatic polymerization. |
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