Biodegradation of N-Methylpyrrolidone by Paracoccus sp. NMD-4 and its degradation pathway

•A highly effective bacterium was isolated from activated sludge for N-Methylpyrrolidone biodegradation.•The optimal pH and temperature for degradation were 7.0 and 30 °C, respectively.•The metabolic pathway for N-Methylpyrrolidone in microorganism was proposed by the first time.

N-Methylpyrrolidone (NMP), a kind of nitrogen-containing heterocyclic pollutant, is widely used in chemical industry. Microbial degradation is an important environmental fate process in soil and water, however, the microbial metabolic mechanism is still unknown. Strain NMD-4, capable of utilizing NMP as the sole source of carbon and nitrogen, was isolated from the activated sludge of a pesticide plant in Jiangsu, China, and identified as Paracoccus sp. based on its physiological–biochemical properties, as well as 16S rRNA gene sequence analysis. The degradation characteristic of NMP by strain NMD-4 was studied in a liquid culture, and the metabolic pathway of NMP by the strain was investigated. Two metabolites, 1-methyl-2,5-pyrrolidinedione and succinic acid, were detected and identified by liquid chromatography-mass spectrometry analysis, and a plausible microbial degradation pathway of NMP was proposed by the first time.