Aerobic biodegradation pathways of pentabromobiphenyl ethers (BDE-99) and enhanced degradation in membrane bioreactor system.
Aerobic biodegradation pathways of pentabromobiphenyl ethers (BDE-99) and enhanced degradation in membrane bioreactor system.
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DOI：
10.2166/wst.2020.322
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发表时间：
2020-07
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通讯作者：
Ke Zhang;Siqiao Yang;Hongbing Luo;Wei Wang;Xiangling Wu;J. Chen;Wei Chen;Jia Chen
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作者：
Ke Zhang;Siqiao Yang;Hongbing Luo;Wei Wang;Xiangling Wu;J. Chen;Wei Chen;Jia Chen
从活性污泥中分离到一株能高效降解五溴联苯醚(BDE-99)的细菌，命名为NLPSJ-22。该菌株与铜绿假单胞菌高度相似，具有100%的相似性。用气相色谱-质谱法对BDE-99的降解产物进行了分析。生化降解途径分析表明，BDE-99通过间位、对位和邻位脱溴逐渐转化为二苯醚。在开环裂解作用下生成苯酚，最终进入三元酸循环。菌株NLPSJ-22对BDE-99的降解符合一级反应动力学。鼠李糖脂显著提高了细胞表面的疏水性和BDE-99的降解率。当加入二苯醚作为共代谢底物时，降解率最高(96%)。在生物强化膜生物反应器(MBR)系统中，BDE-99被强烈降解，反应器在35天左右达到稳定状态。BDE-99的降解率达80%以上，显著高于对照体系。MiSeq测序结果表明，红球菌属、芽孢杆菌属、假单胞菌属、伯克霍尔德氏菌属和狮身人面团菌是膜生物反应器中降解BDE-99的主要细菌群落。在生物强化反应器中，假单胞菌数量显著增加，相对丰度从5%增加到24%。
A bacterial strain capable of efficiently degrading pentabromobiphenyl ether (BDE-99) was isolated from activated sludge and named as NLPSJ-22. This strain was highly close to Pseudomonas asplenii with 100% similarity. The degradation products of BDE-99 were analyzed by gas chromatography mass spectrometry. The biochemical degradation pathways analysis indicated that BDE-99 gradually transformed to diphenyl ether by meta-, para- and ortho-debromination. It became phenol under the action of ring-opening cracking and finally entered the tricarboxylic acid cycle. The degradation of BDE-99 by strain NLPSJ-22 conformed to the first-order reaction kinetics. Rhamnolipid significantly improved the cell-surface hydrophobicity and the degradation of BDE-99. The highest degradation efficiency (96%) was achieved when diphenyl ether as co-metabolic substrate was added. In the bioaugmentation membrane bioreactor (MBR) system, BDE-99 was intensively degraded, and the reactor reached a steady state in about 35 days. The degradation rate of BDE-99 was over 80%, which was significantly higher than that of the control system. MiSeq sequencing results indicated that the genera of Rhodococcus, Bacillus, Pseudomonas, Burkholderia, and Sphingobium were the predominant bacterial communities responsible for BDE-99 biodegradation in the MBR. Pseudomonas increased significantly in the bioaugmented reactor with the relative abundance increasing from 5% to 24%.