Salam L B, Ilori M O, Amund O O, Numata M, Horisaki T, Nojiri H
Department of Microbiology, University of Lagos, Akoka, Lagos, Nigeria,
Environ Sci Pollut Res Int. 2014;21(15):9311-24. doi: 10.1007/s11356-014-2855-2. Epub 2014 Apr 15.
Four bacterial strains isolated from hydrocarbon-contaminated soils in Lagos, Nigeria, displayed extensive degradation abilities on carbazole, an N-heterocyclic aromatic hydrocarbon. Physicochemical analyses of the sampling sites (ACPP, MWO, NESU) indicate gross pollution of the soils with a high hydrocarbon content (157,067.9 mg/kg) and presence of heavy metals. Phylogenetic analysis of the four strains indicated that they were identified as Achromobacter sp. strain SL1, Pseudomonas sp. strain SL4, Microbacterium esteraromaticum strain SL6, and Stenotrophomonas maltophilia strain BA. The rates of degradation of carbazole by the four isolates during 30 days of incubation were 0.057, 0.062, 0.036, and 0.050 mg L(-1) h(-1) for strains SL1, SL4, SL6, and BA. Gas chromatographic (GC) analyses of residual carbazole after 30 days of incubation revealed that 81.3, 85, 64.4, and 76 % of 50 mg l(-1) carbazole were degraded by strains SL1, SL4, SL6, and BA, respectively. GC-mass spectrometry and high-performance liquid chromatographic analyses of the extracts from the growing and resting cells of strains SL1, SL4, and SL6 cultured on carbazole showed detection of anthranilic acid and catechol while these metabolites were not detected in strain BA under the same conditions. This study has established for the first time carbazole angular dioxygenation and mineralization by isolates from African environment.
从尼日利亚拉各斯受碳氢化合物污染的土壤中分离出的四株细菌，对N-杂环芳烃咔唑具有广泛的降解能力。对采样点（ACPP、MWO、NESU）的物理化学分析表明，土壤受到严重污染，碳氢化合物含量高（157,067.9毫克/千克）且存在重金属。对这四株菌株的系统发育分析表明，它们分别被鉴定为无色杆菌属菌株SL1、假单胞菌属菌株SL4、酯芳香微杆菌属菌株SL6和嗜麦芽窄食单胞菌属菌株BA。在30天的培养过程中，这四株分离菌株对咔唑的降解速率分别为：菌株SL1为0.057毫克·升⁻¹·小时⁻¹，菌株SL4为0.062毫克·升⁻¹·小时⁻¹，菌株SL6为0.036毫克·升⁻¹·小时⁻¹，菌株BA为0.050毫克·升⁻¹·小时⁻¹。培养30天后对残留咔唑进行气相色谱（GC）分析发现，50毫克/升咔唑分别被菌株SL1、SL4、SL6和BA降解了81.3%、85%、64.4%和76%。对在咔唑上培养的菌株SL1、SL4和SL6的生长细胞和静止细胞提取物进行的GC-质谱分析和高效液相色谱分析显示，检测到了邻氨基苯甲酸和儿茶酚，而在相同条件下菌株BA中未检测到这些代谢产物。本研究首次证实了非洲环境分离株对咔唑的角双加氧作用和矿化作用。
