Advances in microbial degradation of phenylurea herbicides

Abstract:

Phenylurea herbicides, ?rst marketed in the mid-20th century, have become one of the most important classes of herbicides and have been widely used for controlling both annual grasses and broad-leaf weeds. With the continuous application of phenylurea herbicides, the residue of these herbicides in the environment was beyond the threshold concentration imposed by legislation, and their environmental hazards gradually became more and more serious. Thus, the environmental behaviors of phenylurea herbicides, such as adsorption, migration, and degradation, have received considerable attention. Researches show that the metabolism of N,N-dimethyl-substituted phenylurea herbicides are mainly initiated by consecutive N demethylation events, followed by hydrolysis of the urea side chain, while the N-methoxy-N-methyl substituted phenylurea herbicides are degraded via cleaving directly the urea side chain by bacteria. The fungal degradation pathways of phenylurea herbicides are more complex, therefore further studies are needed. In this article, we summarized the latest progress in the research of phenylurea-degrading microorganisms and their metabolic pathways, which will provide the reference for the feasible bioremediation strategy on phenylurea herbicides contaminated environments.