Qi Yun, Zhao Lin, Olusheyi Ojekunle Z, Tan Xin
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
J Environ Sci (China). 2007;19(3):332-7. doi: 10.1016/s1001-0742(07)60054-0.
A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37 degrees C. It can utilize several (halo)aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30 degrees C with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no (chloro)catechol 2,3-dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.
开展了一项研究，以比较两种原始土壤和一种受污染的污水污泥中2-氯苯甲酸、3-氯苯甲酸和4-氯苯甲酸降解菌的多样性。这些样品中含有截然不同的单氯苯甲酸降解菌种群。尽管在未受污染的土壤中分离出的培养物比受污染土壤中的少，但微生物种群将氯苯甲酸矿化的能力却很普遍。3-氯苯甲酸和4-氯苯甲酸降解菌比2-氯苯甲酸降解菌更多样化。从污水污泥中分离出了一株菌株。根据其表型、化学分类学特性和16S rRNA基因，该菌株S-7被归类为红平红球菌。该菌株能在4至37摄氏度的温度下生长。它能利用几种（卤）芳香族化合物。此外，菌株S-7能在10至30摄氏度的温度范围内以3-氯苯甲酸作为唯一碳源生长并利用，同时化学计量地释放氯离子。这种耐低温能力对低温地区的生物修复具有重要意义。该菌株的无细胞提取物中存在儿茶酚和氯儿茶酚1,2-双加氧酶活性，但未检测到（氯）儿茶酚2,3-双加氧酶活性。对红平红球菌S-7提取物进行的光谱转化分析表明，从3-氯苯甲酸中积累了一种具有与氯-顺,顺-粘康酸相似紫外光谱的化合物。基于这些结果，我们提出S-7通过改良的邻位裂解途径降解3-氯苯甲酸。
