Department of Microbiology, Bose Institute, Kolkata, India.
FEMS Microbiol Lett. 2010 Dec;313(2):103-10. doi: 10.1111/j.1574-6968.2010.02129.x. Epub 2010 Oct 22.
The present study describes the assimilation of phenanthrene by an aerobic bacterium, Ochrobactrum sp. strain PWTJD, isolated from municipal waste-contaminated soil sample utilizing phenanthrene as a sole source of carbon and energy. The isolate was identified as Ochrobactrum sp. based on the morphological, nutritional and biochemical characteristics as well as 16S rRNA gene sequence analysis. A combination of chromatographic analyses, oxygen uptake assay and enzymatic studies confirmed the degradation of phenanthrene by the strain PWTJD via 2-hydroxy-1-naphthoic acid, salicylic acid and catechol. The strain PWTJD could also utilize 2-hydroxy-1-naphthoic acid and salicylic acid, while the former was metabolized by a ferric-dependent meta-cleavage dioxygenase. In the lower pathway, salicylic acid was metabolized to catechol and was further degraded by catechol 2,3-dioxygenase to 2-hydroxymuconoaldehyde acid, ultimately leading to tricarboxylic acid cycle intermediates. This is the first report of the complete degradation of a polycyclic aromatic hydrocarbon molecule by Gram-negative Ochrobactrum sp. describing the involvement of the meta-cleavage pathway of 2-hydroxy-1-naphthoic acid in phenanthrene assimilation.
本研究描述了一株好氧细菌 Ochrobactrum sp. 菌株 PWTJD 对菲的同化作用，该菌株从受城市垃圾污染的土壤样本中分离得到，能够以菲作为唯一的碳源和能源。根据形态学、营养和生化特征以及 16S rRNA 基因序列分析，将该分离物鉴定为 Ochrobactrum sp.。结合色谱分析、耗氧测定和酶学研究，证实了 PWTJD 菌株通过 2-羟基-1-萘酸、水杨酸和儿茶酚降解菲。PWTJD 菌株还可以利用 2-羟基-1-萘酸和水杨酸，而前者是由铁依赖性的间位裂解双加氧酶代谢的。在下游途径中，水杨酸代谢为儿茶酚，然后进一步被儿茶酚 2,3-双加氧酶降解为 2-羟甲基戊二醛酸，最终导致三羧酸循环中间产物。这是首次报道革兰氏阴性菌 Ochrobactrum sp. 完全降解多环芳烃分子的情况，描述了 2-羟基-1-萘酸的间位裂解途径在菲同化中的参与。
