Abstract: A bacterial strain W12 that could utilize pyridine as the sole source of carbon and nitrogen was isolated from an activated sludge reactor and was identified as the species of Paracoccus denitrificans. The strain was resistant to hygromycin and spectinomycin. In the degradation experiments, the strain could degrade pyridine of 505.4 mg/L in 26 hours completely, but could not degrade phenol or quinoline. The plasmid extraction tests indicate that the W12 harbores two plasmids, and its degradative ability decrease sharply when the plasmids are eliminated, implying that the plasmids may be responsible for the pyridine biodegradation.

Key words: Paracoccus denitrificans, pyridine, biodegradation, plasmid

摘要： 从活性污泥中筛选了一株能以吡啶为唯一碳、氮源的细菌，经鉴定为脱氮副球菌（Paracoccus denitrificans W12）。W12菌具有壮观霉素和潮霉素抗性。降解实验结果表明，W12菌能够将505.4mg/L的高浓度吡啶在26小时内完全降解，但不具有降解苯酚和喹啉的能力。质粒提取实验结果显示，W12菌含有两个大质粒，消除质粒后菌株的吡啶降解能力明显低于野生菌，因此该菌株所携质粒可能与W12菌的吡啶降解能力有关。

关键词: 脱氮副球菌, 吡啶, 生物降解, 质粒