School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
Biomed Res Int. 2017;2017:2564363. doi: 10.1155/2017/2564363. Epub 2017 Dec 13.
Indole and its derivatives are typical nitrogen heterocyclic compounds and have been of immense concern since they are known for the risk of their toxic, recalcitrant, and carcinogenic properties for human and ecological environment. In this study, a Gram-negative bacterial strain of eliminating indole was isolated from a coking wastewater. The strain was confirmed as L1 based on the physiological and biochemical characterization and 16S ribosomal DNA (rDNA) gene sequence homology. 400 mg/L indole could be completely removed within 48 h by the strain on the optimum condition of 37°C, pH 7.4, and 150 rpm. The organic nitrogen was converted to NH-N and then to NO and the organic carbon was partially transferred to CO during the indole biodegradation. The metabolic pathways were proposed to explain the indole degradation based on the liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis of indigo, 4-(3-Hydroxy-1H-pyrrol-2-yl)-2-oxo-but-3-enoic acid, and isatin. The toxicity of the biodegradation products was evaluated using the Microtox test, which revealed that the metabolites were more toxic than indole. Our research holds promise for the potential application of L1 for NHCs degradation, production of indigoids, and soil remediation as well as treatment of indole containing wastewater.
吲哚及其衍生物是典型的含氮杂环化合物，由于其毒性、难降解性和致癌性，对人类和生态环境构成了巨大威胁，因此一直受到广泛关注。本研究从焦化废水中分离到一株能够消除吲哚的革兰氏阴性细菌菌株，根据生理生化特性和 16S 核糖体 DNA（rDNA）基因序列同源性，将该菌株确认为 L1。在最适条件（37°C、pH7.4、150rpm）下，该菌株在 48h 内可完全去除 400mg/L 的吲哚。在吲哚生物降解过程中，有机氮转化为 NH-N，然后转化为 NO，部分有机碳转化为 CO。根据靛蓝、4-(3-羟基-1H-吡咯-2-基)-2-氧代-丁-3-烯酸和色胺的液相色谱串联质谱（LC-MS/MS）分析，提出了吲哚降解的代谢途径。采用 Microtox 试验评价了生物降解产物的毒性，结果表明代谢产物的毒性比吲哚更强。本研究为 L1 用于 NHCs 降解、靛蓝类物质的生产、土壤修复以及含吲哚废水的处理提供了潜在的应用前景。
