Biodegradation of seven phthalate esters by Bacillus mojavensis B1811
Biodegradation of seven phthalate esters by Bacillus mojavensis B1811
复制标题
DOI：
10.1016/j.ibiod.2018.04.006
复制
发表时间：
2018-08-01
影响因子：
4.8
通讯作者：
Li, Xiuting
中科院分区：
文献类型：
--
作者：
Zhang, Jingfan;Zhang, Chengnan;Li, Xiuting
邻苯二甲酸酯（PAEs）是使用最广泛的增塑剂之一，被认为对环境和人类健康构成威胁。研究了mojavensis B1811对7种邻苯二甲酸酯（PAEs）的高效生物降解。结果表明，菌株B1811在摇摇条件下能在4种无矿盐介质（MSM）中几乎完全降解邻苯二甲酸二（2-乙基己基）酯（DEHP）、邻苯二甲酸二丁酯（DBP）、邻苯二甲酸二丁酯（BBP）和邻苯二甲酸二戊酯（DPP），而具有短烷基链的邻苯二甲酸二甲酯（DMP）和邻苯二甲酸二乙酯（DEP）在相同条件下的降解率仅为5.9%和42.9%。酯酶活性测定也表明，较长烷基链PAEs诱导的酯酶比活性远高于较短烷基链PAEs诱导的酯酶。采用高效液相色谱-电喷雾电离四极杆飞行时间质谱（HPLC-ESI-QTOF-MS）对7种PAEs的主要代谢物进行鉴定。PAEs先降解为相应的邻苯二甲酸单酯，再降解为邻苯二甲酸；邻苯二甲酸迅速降解生成苯甲酸，苯甲酸随后转化为原儿茶酸，最终转化为CO2和H2O。得到了最佳生物降解条件，指数模型是表征PAEs耗竭的最佳模型。因此，mojavensis B1811在PAEs污染环境的生物修复中具有很大的应用潜力。
Phthalate esters (PAEs) are one of the most widely used groups of plasticizers and have been considered threats to the environment and human health. This study investigated the efficient biodegradation of seven phthalate esters (PAEs) by Bacillus mojavensis B1811. The results showed that di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP) and dipentyl phthalate (DPP) could be almost completely degraded by strain B1811 within four gays in,mineral salt medium (MSM) under shaking conditions, while only 5.9% of the dimethyl phthalate (DMP) and 42.9% of the diethyl phthalate (DEP) present, which both have short alkyl chains, were degraded by strain B1811 under the same conditions. An esterase activity assay also indicated that the specific activities of esterases induced by PAEs with longer alkyl chains were much higher than those of esterases induced by PAEs with short alkyl chains. High-performance liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS) was applied to identify the major metabolites of the seven PAEs. The PAEs were first degraded to the corresponding phthalate monoesters and then degraded to phthalic acid; phthalic acid was rapidly degraded to produce benzoic acid which was subsequently converted to protocatechuate and ultimately transformed to CO2 and H2O. The optimal conditions for biodegradation were also obtained and an exponential model was the best model to represent the PAEs depletion. It is therefore concluded that B. mojavensis B1811 offers great application potential in the bioremediation of environments polluted with PAEs.