Li D Y, Eberspächer J, Wagner B, Kuntzer J, Lingens F
Institut für Mikrobiologie, Universität Hohenheim, Stuttgart, Germany.
Appl Environ Microbiol. 1991 Jul;57(7):1920-8. doi: 10.1128/aem.57.7.1920-1928.1991.
A bacterium which utilizes 2,4,6-trichlorophenol (TCP) as a sole source of carbon and energy was isolated from soil. The bacterium, designated strain GP1, was identified as an Azotobacter sp. TCP was the only chlorinated phenol which supported the growth of the bacterium. Resting cells transformed monochlorophenols, 2,6-dichlorophenol, and 2,3,6-trichlorophenol. Phenol and a number of phenolic compounds, including 4-methylphenol, all of the monohydroxybenzoates, and several dihydroxybenzoates, were very good carbon sources for Azotobacter sp. strain GP1. The organism utilized up to 800 mg of TCP per liter; the lag phase and time for degradation, however, were severely prolonged at TCP concentrations above 500 mg/liter. Repeated additions of 200 mg of TCP per liter led to accelerated degradation, with an optimum value of 100 mg of TCP per liter per h. TCP degradation was significantly faster in shaken than in nonshaken cultures. The optimum temperature for degradation was 25 to 30 degrees C. Induction studies, including treatment of the cells with chloramphenicol prior to TCP or phenol addition, revealed that TCP induced TCP degradation but not phenol degradation and that phenol induced only its own utilization. Per mol of TCP, 3 mol of Cl- was released. 2,6-Dichloro-p-benzoquinone was detected in the resting-cell medium of Azotobacter sp. strain GP1. By chemical mutagenesis, mutants blocked in either TCP degradation or phenol degradation were obtained. No mutant defective in the degradation of both phenols was found, indicating separate pathways for the dissimilation of the compounds. In some of the phenol-deficient mutants, pyrocatechol was found to accumulate, and in some of the TCP-deficient mutants, 2,6-dichlorohydroquinone was found to accumulate.
从土壤中分离出一种以2,4,6 - 三氯苯酚（TCP）作为唯一碳源和能源的细菌。该细菌被命名为GP1菌株，鉴定为固氮菌属。TCP是唯一支持该细菌生长的氯代苯酚。静止细胞可转化一氯苯酚、2,6 - 二氯苯酚和2,3,6 - 三氯苯酚。苯酚以及一些酚类化合物，包括4 - 甲基苯酚、所有单羟基苯甲酸酯和几种二羟基苯甲酸酯，都是固氮菌属GP1菌株很好的碳源。该微生物每升可利用高达800毫克的TCP；然而，当TCP浓度高于500毫克/升时，延迟期和降解时间会严重延长。每升重复添加200毫克的TCP会导致降解加速，最佳值为每升每小时100毫克的TCP。在振荡培养中TCP的降解明显快于非振荡培养。降解的最适温度为25至30摄氏度。诱导研究，包括在添加TCP或苯酚之前用氯霉素处理细胞，结果表明TCP诱导TCP降解但不诱导苯酚降解，而苯酚仅诱导其自身的利用。每摩尔TCP会释放出3摩尔的Cl-。在固氮菌属GP1菌株的静止细胞培养基中检测到了2,6 - 二氯对苯醌。通过化学诱变，获得了在TCP降解或苯酚降解方面受阻的突变体。未发现两种酚类降解均有缺陷的突变体，这表明这些化合物的异化途径是分开的。在一些苯酚缺陷型突变体中，发现儿茶酚会积累，而在一些TCP缺陷型突变体中，发现2,6 - 二氯对苯二酚会积累。
