Isolation and characterization of a novel cinosulfuron degrading Kurthia sp. from a methanogenic microbial consortium

A novel bacterial strain LAM0713 was isolated from a methanogenic bacterial complexes and identified as Kurthia sp. based on morphological, cultural, physio-biochemical characteristics and analysis of 16S rDNA sequence. Strain LAM0713 was found to be capable of utilizing cinosulfuron as sole nitrogen source for growth over a wide range of temperature (20-40 °C) and pH (5.0-9.0). Response surface methodology was used to optimize the degradation conditions. Strain LAM0713 could efficiently degrade 92.4% of initially supplemented 50 mg·L(1) cinosulfuron under the optimum conditions (pH 6.9, 31.8 °C) within 5 days. Five intermediates formed during cinosulfuron degradation were detected by liquid chromatography mass spectrometry (LC-MS), and a metabolic pathway for cinosulfuron degradation was proposed via cleavage of the sulfonylurea bridge. It is the first report showing that Kurthia sp. strain could degrade sulfonylurea herbicides, suggesting that strain LAM0713 may provide new insight into microbial degradation of herbicides.