Characterization of isoproturon biodegradation pathway in Sphingobium sp. YBL2

In our previous study, a phenylurea herbicides degrading strain Sphingobium sp. YBL2 was isolated. In the present study, the degradation pathway of IPU (Isoproturon) in strain YBL2 was investigated by intermediate metabolites identification. HPLC and/or MS/MS analysis showed that, three intermediate metabolites, MDIPU (1-(4-isopropylphenyl)-3-methylurea), DDIPU (1-(4-isopropylphenyl) urea) and 4-IA (4-Isopropylaniline) was produced by strain YBL2. All of these intermediate metabolites could also be efficiently degraded by strain YBL2. In addition, IPU-induced aniline dioxygenase activity and catechol 2,3-dioxygenase activity were detected in strain YBL2. In combination of all these results, we deduced that the metabolic pathway of IPU in strain YBL2 involves two successive N-demethylations, followed by cleavage of the urea side chain and aromatic ring.

► Three metabolites were detected during IPU degradation by strain YBL2.
► Aniline dioxygenase and Catechol 2,3-dioxygenase activity can be induced by IPU.
► IPU and its metabolites can be completely degraded by strain YBL2.
► IPU degradation pathway in strain YBL2 was proposed.