Department of Biochemistry, Gulbarga University, Karnataka, India.
FEMS Microbiol Lett. 2011 Jul;320(2):128-34. doi: 10.1111/j.1574-6968.2011.02301.x. Epub 2011 May 31.
The chrysene-degrading bacterium Pseudoxanthomonas sp. PNK-04 was isolated from a coal sample. Three novel metabolites, hydroxyphenanthroic acid, 1-hydroxy-2-naphthoic acid and salicylic acid, were identified by TLC, HPLC and MS. Key enzyme activities, namely 1-hydroxy-2-naphthoate hydroxylase, 1,2-dihydroxynaphthalene dioxygenase, salicylaldehyde dehydrogenase and catechol-1,2-dioxygenase, were noted in the cell-free extract. These results suggest that chrysene is catabolized via hydroxyphenanthroic acid, 1-hydroxy-2-naphthoic acid, salicylic acid and catechol. The terminal aromatic metabolite, catechol, is then catabolized by catechol-1,2-dioxygenase to cis,cis-muconic acid, ultimately forming TCA cycle intermediates. Based on these studies, the proposed catabolic pathway for chrysene degradation by strain PNK-04 is chrysene → hydroxyphenanthroic acid → 1-hydroxy-2-naphthoic acid → 1,2-dihydroxynaphthalene → salicylic acid → catechol →cis,cis-muconic acid.
从煤样中分离到一株降解荧蒽的细菌 Pseudoxanthomonas sp. PNK-04。通过 TLC、HPLC 和 MS 鉴定了三种新的代谢物：苯酚羧酸、1-羟基-2-萘酸和水杨酸。细胞提取物中存在关键酶活性，如 1-羟基-2-萘酸羟化酶、1,2-二羟基萘二加氧酶、水杨醛脱氢酶和儿茶酚-1,2-双加氧酶。这些结果表明，荧蒽通过苯酚羧酸、1-羟基-2-萘酸、水杨酸和儿茶酚进行代谢。末端芳香族代谢物儿茶酚进一步被儿茶酚-1,2-双加氧酶代谢为顺式,顺式-粘康酸，最终形成 TCA 循环中间产物。基于这些研究，PNK-04 菌株降解荧蒽的代谢途径为荧蒽→苯酚羧酸→1-羟基-2-萘酸→1,2-二羟基萘→水杨酸→儿茶酚→顺式,顺式-粘康酸。
