Jiangsu Key Lab for Solid Organic Waste Utilization , Nanjing , Jiangsu 210095 , People's Republic of China.
J Agric Food Chem. 2019 Jun 19;67(24):6819-6827. doi: 10.1021/acs.jafc.9b00707. Epub 2019 Jun 6.
Napropamide [ N, N-diethyl-2-(1-naphthalenyloxy)propenamide, NAP] is a highly efficient and broad-spectrum amide herbicide. Little is known about the bacterial catabolism of its different enantiomers. Here, we report the isolation of two NAP-degrading strains of Sphingobium sp., A1 and B2, and the different catabolic pathways of different enantiomers in these two strains. Strain A1 dioxygenated NAP at different positions of the naphthalene ring of different enantiomers, leading to the complete degradation of R-NAP while producing a dead-end product from S-NAP. Strain B2 cleaved the amido bonds of both enantiomers, but only the product from S-NAP could be further transformed to form α-naphthol and mineralize in strain B2. The degradation rates of R-NAP and S-NAP in the combination degradation by strains A1 and B2 were 24.8 and 7.5 times that in the single-strain degradation by strain B2 or A1, respectively, showing enhanced synergistic catabolism between strains A1 and B2. This study provides new insights into the enantioselective catabolic network of the chiral herbicide NAP in microorganisms.
萘丙胺[ N，N-二乙基-2-（1-萘氧基）丙烯酰胺，NAP]是一种高效广谱的酰胺类除草剂。关于其不同对映异构体的细菌代谢知之甚少。在这里，我们报告了两种能够降解萘丙胺的鞘氨醇单胞菌（ Sphingobium sp.）菌株 A1 和 B2 的分离，并研究了这两种菌株中不同对映异构体的不同代谢途径。菌株 A1 在不同对映异构体的萘环的不同位置上双加氧酶化 NAP，导致 R-NAP 完全降解，而 S-NAP 则产生无出路的产物。菌株 B2 切断了两种对映异构体的酰胺键，但只有 S-NAP 的产物可以进一步转化为α-萘酚并在菌株 B2 中矿化。在菌株 A1 和 B2 的组合降解中，R-NAP 和 S-NAP 的降解速率分别是菌株 B2 或 A1 单一菌株降解的 24.8 倍和 7.5 倍，表明菌株 A1 和 B2 之间存在增强的协同代谢作用。本研究为微生物中手性除草剂 NAP 的对映选择性代谢网络提供了新的见解。
