Isolation and characterization of the cotinine-degrading bacterium Nocardioides sp. Strain JQ2195
Isolation and characterization of the cotinine-degrading bacterium Nocardioides sp. Strain JQ2195
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可替宁降解菌诺卡氏菌的分离和表征。
DOI：
10.1016/j.jhazmat.2018.04.003
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发表时间：
2018
影响因子：
13.6
通讯作者：
He Jian
中科院分区：
文献类型：
--
作者：
Qiu Jiguo;Zhang Yanting;Zhao Lingling;He Qin;Jiang Ji;ong;Hong Qing;He Jian
可替宁是尼古丁的主要代谢产物，在环境中较难降解，且对人体健康有潜在的危害。迄今为止，对可替宁的生物降解过程知之甚少。本研究从城市污水中分离到一株细菌JQ 2195，经鉴定为拟诺卡氏菌属（Nocardioidessp.）根据形态、生理特征和16 S rRNA基因进行系统发育分析。该菌株利用可替宁作为唯一碳源，在32 h内完全降解0.5 g L-1可替宁。JQ 2195对可替宁的最佳降解条件为30 °C和pH 7.0。通过UV/维斯光谱和液相色谱-飞行时间质谱联用技术鉴定了两种可替宁降解中间体6-羟基-可替宁和6-羟基-3-琥珀酰吡啶。此外，约一半的可替宁被转化为6-羟基-3-琥珀酰基吡啶，这是一个生物催化的增值化合物。当使用2，6-二氯酚靛酚作为电子受体时，含有可诱导的可替宁脱氢酶的无细胞提取物可以将可替宁转化为6-羟基-可替宁，活性为40 ± 6 mUnmg−1。
Cotinine, the primary nicotine metabolite, not only more stable and more difficult to degrade in the environment but is a potential health risk to human. To date, little is known about the biodegradation process of cotinine. In this study, a bacterial strain JQ2195 was isolated from municipal wastewater and was identified asNocardioidessp. based on morphological, physiological characteristics, and 16 S rRNA gene phylogenetic analysis. This strain utilized cotinine as a sole carbon source and degraded 0.5 g L−1cotinine completely within 32 h. Optimum degradation of cotinine by JQ2195 was at 30 °C and pH 7.0. Two cotinine degradation intermediates were identified as 6-hydroxy-cotinine and 6-hydroxy-3-succinoylpyridine by UV/VIS spectroscopy and liquid chromatography coupled with time-of-flight mass spectrometry. In addition, about half of cotinine was transformed to 6-hydroxy-3-succinoylpyridine which was a value-added compound for biocatalysis. When 2,6-dichlorophenolindophenol was used as an electron acceptor, the cell-free extract containing the inducible cotinine dehydrogenase could convert cotinine into 6-hydroxy-cotinine with the activity 40 ± 6 mUnmg−1.