N,N-Dimethylformamide (DMF) is one of the most common xenobiotic chemicals and can be easily emitted into the environment, where it causes harm to human beings. Herein, an efficient DMF-degrading strain DM1 was isolated and identified as Methylobacterium sp. This strain can use DMF as the sole source of carbon and nitrogen. Whole genome sequencing of strain DM1 reveals that it has a 5.66 Mbp chromosome and a 200 kbp mega-plasmid. The plasmid pLVM1 specifically harbors the genes essential for the initial steps of DMF degradation, and the chromosome carries the genes facilitating subsequent methylotrophic metabolism. By analyzing the transcriptome sequencing (RNA-seq) data, the complete mineralization pathway and redundant gene clusters of DMF degradation were elucidated. The dimethylformidase (DMFase) gene was heterologously expressed, and DMFase was purified and characterized. Plasmid pLVM1 is catabolically crucial for the DMF utilization, as evidenced by the phenotype identification of the plasmid-free strain. Taken together, this study systematically unravels the molecular mechanism of DMF degradation by MethylobacteriumIMPORTANCEN,N-Dimethylformamide (DMF) is a hazardous pollutant that has been used in the chemical industry, pharmaceutical manufacturing, and agriculture. Biodegradation as a method for removing DMF has received increasing attention. Here, we identified an efficient DMF degrader, Methylobacterium sp. DM1, and characterized the complete DMF mineralization pathway and enzymatic properties of DMFase in this strain. This study provides insights in the molecular mechanism and evolutionary advantage of DMF degradation facilitated by plasmid pLVM1 and redundant genes in strain DM1, suggesting emergence of new ecotypes of Methylobacterium. Copyright © 2019 American Society for Microbiology.
Journal: Applied and environmental microbiology