Genomic characterization, kinetics, and pathways of sulfamethazine biodegradation by Paenarthrobacter sp. A01. (October 2019)

• Record Type: Journal Article
• Authors: Cao, Lijia; Zhang, Jiayu; Zhao, Renxin; Deng, Yu; Liu, Jie; Fu, Wenjie; Lei, Yusha; Zhang, Tong; Li, Xiaoyan; Li, Bing
• Is Part Of: Environment international. Volume 131(2019)
• Publication Date: 2019-10
• Subjects: Sulfamethazine -- Biodegradation -- Paenarthrobacter -- Pathways -- sad genes; Environmental protection -- Periodicals; Environmental health -- Periodicals; Environmental monitoring -- Periodicals; Environmental Monitoring -- Periodicals; Environnement -- Protection -- Périodiques; Hygiène du milieu -- Périodiques; Environnement -- Surveillance -- Périodiques; Environmental health; Environmental monitoring; Environmental protection; Periodicals; 333.705
• DOI: 10.1016/j.envint.2019.104961
• Languages: English
• ISSNs: 0160-4120

Abstract

Abstract: Biodegradation is an important route for the removal of sulfamethazine (SMZ), one of the most commonly used sulfonamide antibiotics, in the environment. However, little information is known about the kinetics, products, and pathways of SMZ biodegradation owing to the complexity of its enzyme-based biotransformation processes. In this study, the SMZ-degrading strain A01 belonging to the genus Paenarthrobacter was isolated from SMZ-enriched activated sludge reactors. The bacterial cells were rod-shaped with transient branches 2.50–4.00 μm in length with most forming in a V-shaped arrangement. The genome size of Paenarthrobacter sp. A01 had a total length of 4, 885, 005 bp with a GC content of 63.5%, and it contained 104 contigs and 55 RNAs. The effects of pH, temperature, initial substrate concentration and additional carbon source on the biodegradation of SMZ were investigated. The results indicated that pH 6.0–7.8, 25 °C and the addition of 0.2 g/L sodium acetate favored the biodegradation, whereas a high concentration of SMZ, 500 mg/L, had an inhibitory effect. The biodegradation kinetics with SMZ as the sole carbon source or 0.2 g/L sodium acetate as the co-substrate fit the modified Gompertz model well with a correlation coefficient (R 2 ) of 0.99. Three biodegradation pathways were proposed involving nine biodegradation products, among which C6 H9 N3 O2 S and C12 H12 N2 were two novel biodegradation products that have not been reported previously. Approximately 90.7% of SMZ was transformed to 2-amino-4, 6-dimethylpyrimidine. Furthermore, sad genes responsible for catabolizing sulfonamides were characterized in A01 with high similarities of 96.0%–100.0%. This study will fill the knowledge gap in the biodegradation of this ubiquitous micropollutant in the aquatic environment. Highlights: SMZ biodegradation by Paenarthrobacter sp. A01 under various conditions was conducted. SMZ biodegradation was inhibited by co-substrate with high concentration. Biodegradation fits the modified Gompertz model well with SMZ as sole carbon source. C6 H9 N3 O2 S and C12 H12 N2 are firstly reported as two novel intermediates. Sulfonamides-catabolizing genes were characterized in Paenarthrobacter sp. A01.