Lambo Adewale J, Patel Thakor R
Department of Biology, Memorial University of Newfoundland, St. John's, NL, Canada.
Curr Microbiol. 2006 Jul;53(1):48-52. doi: 10.1007/s00284-005-0194-8. Epub 2006 Jun 9.
A biphenyl-utilizing bacterium isolated from polychlorinated biphenyls (PCBs)-contaminated soils grew on tryptic soy at temperatures between 4 and 40 degrees C. The Gram-negative rod bacterium formed yellow colonies on nutrient agar and it denitrified nitrate to nitrogen. Analysis of cellular fatty acids showed that it was most closely related to Hydrogenophaga taeniospiralis. At 5 degrees C, biphenyl-grown cells cometabolically degraded di- and trichlorinated isomers of PCBs in 10 ppm of Aroclor 1248. At 30 degrees C, PCBs that were removed included a congener with four chlorine substituents. At 5 degrees C, cells transformed 2,4'-dichlorobiphenyl (2,4'-DCB) and accumulated ortho-chlorinated meta-cleavage product as a stable metabolite. Analysis of extracts of culture supernatant by gas chromatography-mass spectrometry indicated that products of transformation of 2,4'-DCB included 2- and 4-chlorobenzoic acid (2- and 4-CBA), suggesting that (chloro)biphenyl-degrading upper-pathway enzymes of the bacterium are active at low temperature. The bacterium Hydrogenophaga sp. IA3-A is a PCB-degrading psychrotolerant strain.
从多氯联苯（PCBs）污染土壤中分离出的一株利用联苯的细菌，在胰蛋白胨大豆培养基上于4至40摄氏度的温度范围内生长。这种革兰氏阴性杆菌在营养琼脂上形成黄色菌落，能将硝酸盐反硝化生成氮气。细胞脂肪酸分析表明，它与螺旋形嗜氢菌最为接近。在5摄氏度时，以联苯为生长底物的细胞通过共代谢作用降解了10 ppm的Aroclor 1248中的二氯和三氯代多氯联苯异构体。在30摄氏度时，被去除的多氯联苯包括一种含有四个氯取代基的同系物。在5摄氏度时，细胞转化了2,4'-二氯联苯（2,4'-DCB），并积累了邻位氯化间位裂解产物作为稳定的代谢物。通过气相色谱-质谱联用仪对培养上清液提取物进行分析表明，2,4'-DCB的转化产物包括2-氯苯甲酸和4-氯苯甲酸（2-CBA和4-CBA），这表明该细菌（氯）联苯降解的上游途径酶在低温下具有活性。嗜氢菌属IA3-A菌株是一种能降解多氯联苯的耐冷菌株。
