Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Beijing 100048, PR China; Beijing Higher Institution Engineering Research Center of Food Additives and Ingredients, Beijing 100048, PR China.
U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038, United States.
Chemosphere. 2019 Jun;225:443-450. doi: 10.1016/j.chemosphere.2019.02.194. Epub 2019 Mar 2.
This study was conducted to investigate the biodegradation of di-(2-ethylhexyl) phthalate (DEHP) by Burkholderia pyrrocinia B1213. The results showed that DEHP at concentration of 500 mg/L in a mineral salt medium containing 1.0% yeast extract can be almost completely degraded (98.05%) by strain B1213. The optimal condition for DEHP degradation was pH 7.0, temperature 30 °C. Moreover, B1213 shows better degradation effect on long-chain PAEs, such as DEHP, which provides a great potential for its use in bioremediation of soils contaminated with PAEs. The kinetic studies showed that DEHP depletion curves fit well to the modified Gompertz model. The mono(2-ethylhexyl) phthalate (MEHP), mono-dibutyl phthalate (MBP), phthalic acid (PA) and 4-oxo-hexanoic acid were identified as the metabolites of DEHP by HPLC-ESI-QTOFMS. The detection of MBP and 4-oxo-hexanoic acid as intermediates prompted us to propose a novel and more complete DEHP biodegradation pathway compared to the classic pathway: DEHP is first degraded to MEHP by esterases, which is then converted to MBP through β-oxidation. Then MBP is degraded to PA by esterases, which is then converted to protocatechuate (PCA) under aerobic conditions rapidly. PCA is ultimately cleaved to generate CO and HO via 4-oxo-hexanoic acid.
本研究旨在探究恶臭假单胞菌 B1213 对邻苯二甲酸二(2-乙基己基)酯（DEHP）的生物降解作用。结果表明，菌株 B1213 能以 1.0%酵母膏为碳源，在含 500mg/L DEHP 的无机盐培养基中几乎完全降解 DEHP（98.05%）。DEHP 降解的最佳条件为 pH7.0、温度 30°C。此外，B1213 对长链邻苯二甲酸酯（如 DEHP）具有更好的降解效果，这为其在修复 PAEs 污染土壤方面的应用提供了巨大潜力。动力学研究表明，DEHP 的消耗曲线与修正的 Gompertz 模型拟合良好。通过高效液相色谱-电喷雾串联飞行时间质谱（HPLC-ESI-QTOFMS）鉴定出 DEHP 的代谢产物为单（2-乙基己基）邻苯二甲酸酯（MEHP）、单丁基邻苯二甲酸酯（MBP）、邻苯二甲酸（PA）和 4-氧代己酸。MBP 和 4-氧代己酸作为中间产物的检测促使我们提出了一条与经典途径相比更为新颖和完整的 DEHP 生物降解途径：酯酶首先将 DEHP 降解为 MEHP，然后通过β-氧化将 MEHP 转化为 MBP。然后，酯酶将 MBP 降解为 PA，在有氧条件下，PA 迅速转化为原儿茶酸（PCA）。最后，PCA 通过 4-氧代己酸生成 CO 和 HO。
