Complete degradation of bisphenol A and nonylphenol by a composite of biogenic manganese oxides and Escherichia coli cells with surface-displayed multicopper oxidase CotA

文献类型： 外文期刊

第一作者： Zhang, Zhen

作者： Zhang, Zhen;Liu, Jin;Liu, Chang;Li, Lin;Ruan, Zhiyong;Zhang, Fuming;Linhardt, Robert J.;Zhang, Zhen

作者机构：

关键词： Endocrine-disrupting chemical; Biodegradation; Spore coat protein A; Manganese oxide; Cell surface display technology

期刊名称：CHEMICAL ENGINEERING JOURNAL （ 影响因子：13.273； 五年影响因子：11.529 ）

ISSN： 1385-8947

年卷期： 2019 年 362 卷

页码：

收录情况： SCI

摘要： Endocrine-disrupting chemicals (EDCs) are a large group of environmental toxicants that pose serious risks to public health. In this study, we report a new method for the complete degradation of EDCs using a dual oxidation-action composite of biogenic manganese oxides and engineered Escherichia coli cells with surface-expressed multicopper oxidase CotA. The cotA gene from a Mn2+-oxidizing bacterium was constructed as a fusion gene "inaQ-N/cotA" with an anchoring motif inaQ-N from Pseudomonas syringae and was expressed in E. coli cells to display catalytic CotA on the cell surface. Under prolonged Mn2+-enriched culturing conditions, the engineered cells were capable of forming microspherical aggregated composites that were mainly composed of ramsdellite (MnO2). The ability of the composite to degrade two EDCs, bisphenol A (BPA) and nonylphenol (NP), was investigated. GC-MS assays identified 7 and 10 degraded intermediates using the C-13 isotope from C-13-labeled BPA and C-13-labeled NP, respectively. The appearance of (CO2)-C-13 from both reaction mixtures revealed mineralization pathways of BPA and NP by this composite. Bioassays using Caenorhabditis elegans as an indicator organism demonstrated that the estrogenic activity of BPA and NP was eliminated by these degradation processes. The reaction of the composite proceeded at an acidic pH and room temperature. A consecutive three-round treatment process showed comparable levels of degradation by the composite in repeated reactions and showed that the activity could be easily recovered. Moreover, the superoxide radical levels of BPA-degradation and NP-degradation were monitored during the 24 h reaction time, and possible BPA-degradation and NP-degradation pathways by the composite were proposed.

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