丛毛睾丸酮单胞菌ZD4-1和铜绿假单胞菌ZD4-3降解芳香烃化合物的机理

从某农药厂二沉池污泥中筛选分离得到两株革兰氏阴性的芳香烃降解菌ZD41和ZD43。经鉴定，它们分别属于Comamonas testosteroni和Pseudomonas aeruginosa。基于16S rDNA 序列的系统分类分析，结果表明，在分类地位上菌株ZD41和ZD43 分别属于两个不同的分类亚组。苯酚降解产物紫外光谱扫描和双加氧酶检测证明，菌株ZD41利用邻裂途径降解苯酚，而ZD43则通过间裂途径降解苯酚，邻裂途径的1,2双加氧酶和间裂途径的2,3双加氧酶都是可诱导的双加氧酶，其活性强烈的依赖于降解底物的出现。芳香烃降解试验结果表明，邻裂和间裂两种途径的降解性能不一样，虽然ZD43降解苯酚的效率要高于菌株ZD41，但是ZD41降解苯酚的pH值范围以及芳烃利用基质谱宽于后者。

Biodegradation Mechanism of Aromatic Compounds by Comamonas testosteroni ZD 4-1 and Pseudomonas aeruginosa ZD4-3

To investigate the characteristic and biochemical mechanism about the biodegradation of aromatic compounds by bacteria, bacterial strains ZD 4 1 and ZD 4 3 were isolated from pesticide manufacturing factory sludge, by growth on phenol as the sole source of carbon and energy, and were identified as Comamonas testosteroni and Pseudomonas aeruginosa . Based on the sequences of 16S rDNA, bacterial strains ZD 4 1 and ZD 4 3 were positioned into two different subgroups. The identification of the intermediates and the detection of the corresponding catabolic enzymes in crude extracts indicated that the strains ZD 4 1 and ZD 4 3 metabolized phenol via ortho pathways and meta pathways, respectively. The results of induction experiment showed that the catechol dioxygenases, both catechol 1,2 dioxygenase (C12O) and catechol 2,3 dioxygenase (C23O), were all inducible. Finally, the results of biodegradation and enzyme assays showed that the biodegradation efficiency of phenol by meta pathways was higher than that by ortho pathways but the former is in an inferiority position in terms of adaptation to pH fluctuation and of growth ability on other aromatic compounds compared with the latter.