取代脲类除草剂的微生物降解

取代脲类除草剂主要用来防除一年生禾本科杂草和阔叶杂草,自20世纪中期推入市场以来,在世界范围内被广泛使用,已成为重要的除草剂之一。随着取代脲类除草剂的持续施用,其在环境中的残留严重超标,危害日益凸显。因此,取代脲类除草剂在环境中的吸附、迁移和降解等行为备受关注。研究表明细菌降解N,N-二甲基取代脲类除草剂主要是通过连续脱甲基作用后断脲桥降解,而降解N-甲氧基-N-甲基取代脲类除草剂是通过脲桥的直接断裂。真菌降解取代脲类除草剂的途径则较为复杂,尚需进一步阐明。本文综述了近年来分离筛选的取代脲类除草剂降解菌株及其降解途径的最新研究进展,为取代脲类除草剂污染环境的生物修复研究提供参考。

Advances in microbial degradation of phenylurea herbicides

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.