一株苯胺降解菌的分离及其苯胺降解特性的研究

Isolation and Characterization of An Aniline-degrading Bacterium

目的:筛选高效苯胺降解菌并研究其降解特性,为利用微生物进行苯胺环境污染物修复奠定基础。方法:利用含苯胺的A15培养基分离筛选苯胺降解菌,探讨苯胺降解最佳条件、降解代谢途径,利用16S rDNA基因扩增测序法对株菌进行分子鉴定。结果:获得了一株以苯胺为惟一碳源、氮源生长的高效苯胺降解菌AN6-4。该菌降解苯胺的最高浓度为2 500mg/L,降解苯胺的最适温度和pH值分别为30℃、7.0;该菌在60h内可以将1 500mg/L浓度的苯胺完全降解;重金属离子对该菌株降解苯胺有不同程度的抑制作用;代谢机制研究表明,该菌株可以诱导合成邻苯二酚-2,3-双加氧酶并分泌到胞外降解苯胺;16S rDNA基因序列同源性比较结果表明该菌属芽孢杆菌的一种。结论:所获得的苯胺降解菌对于研究苯胺降解机制和苯胺环境污染物的生物修复具有重要的理论和潜在应用价值。

Objective： Screening of high efficient aniline - degrading bacteria and to study their degradation properties can provide basis for the use of microorganisms to carry out environmental restoration. Method： The A15 medium containing aniline was used to isolate aniline- degrading bacteria. The best conditions for aniline degradation and degradation pathway were explored, and the amplified 16S rDNA gene sequence was used to the molecular identification of bacterium strain. Result： A high efficient aniline- degrading bacterium named AN6- 4 was obtained by using aniline as the sole carbon, nitrogen sources. The highest concentration of aniline that AN6 - 4 could degrade was 2 500mg/L, with the optimum temperature and pH value ofT.0 and 30℃, respectively; AN6 - 4 could degrade aniline at a concentration as high as 1 500mg/L in 60h; Heavy metal ions had different degrees of inhibition on aniline degradation; Metabolic pathway research showed that AN6 - 4 could induce the synthesis of catechol - 2, 3 - dioxygenase and the enzyme was released into the extracellular environment to degrade aniline; Homolog comparison analysis of 16S rDNA gene sequences showed that AN5 - 3 belongs to the genus Bacillus. Conclusion： The aniline - degrading bacterium thus obtained was a valuable material for the study of the mechanism of aniline degradation and for the practical application to bio - restoration of enviroumental contamination.