微生物降解对氯苯胺的一条新代谢途径

A novel metabolism pathway for the biodegradation of chloroanilines

迄今为止的研究报道表明,对氯苯胺的生物降解只能以邻位途径或修饰邻位途径进行。采用HPLC、液相色谱质谱联用技术(LC/MS)对Diaphorobacter PCA039菌株降解对氯苯胺的中间代谢产物进行了分析和鉴定,结果表明,对氯苯胺经PCA039菌株的降解形成了氯代邻苯二酚,5-氯-4草酰巴豆酸,5-氯-2-氧戊烯酸,5-氯-2-氧-4-羟戊酸,氯代乙酸等中间代谢产物,这些都是典型的间位代谢途径(meta-pathway)的中间物质,说明Diaphorobacter PCA039菌株以间位裂解途径对对氯苯胺进行降解。这对于对氯代胺的生物降解代谢研究、代谢机理及其遗传表达调控研究具有意义。

Up to date, p-chloroaniline was reported to be biodegraded only through ortho-or modified ortho-cleavage pathway. In this paper, the intermediates of p-chloroaniline metabolized by strain Diaphorobacter PCA039 were analyzed and identified by HPLC and LC/MS methods. The results showed that intermediates such as 4-chlorocatechol, 2-hydroxy-5-chloromuconic semialdehyde, 5-chloro-4-oxalocrotonate, 5-chloro-2-oxo-4-hydroxypentanote, chloro-acetate were formed and consumed in order during the degradation of p-chloroaniline by strain Diaphorobacter PCA039.These compounds are the intermediates of a typical recta-cleavage pathway. In addition, strain Diaphorobacter PCA039 could produce the induced catechol 2, 3-dioxygenase when it grows on p-chloroaniline as sole carbon, nitrogen and energy sources, and use the intermediates of the recta-cleavage pathway such as catechol, 4-chlorocatechol, 2-hydroxy-5-chloromuconic semialdehyde as sole carbon and energy sources. Combining its physiological and biochemical properties and the results of LC/MS analysis, it was concluded that strain Diaphorobacter PCA039 could also degrade p-chloroaniline through recta-cleavage pathway as Fig. 4, which is a new pathway for the biodegradation of p-chloroaniline. It is significant to the study of biodegradation, metabolic mechanism, properties of the enzymes and the expression and regulation of the genes involved in the degradation of p-chloroaniline.