Biomineralization of N,N-dimethylformamide by Paracoccus sp. strain DMF

N,N-dimethylformamide (DMF) is a man-made compound that is widely used as a solvent for the synthesis of various organic compounds. In this study, a bacterial strain Paracoccus sp. DMF capable of using DMF as the sole carbon, nitrogen and energy source, was isolated from an enrichment culture developed using activated sludge from domestic waste water treatment unit as the source inoculum. The strain DMF was characterized by biochemical tests and 16S rDNA sequence analysis, to be belonging to the genus Paracoccus. Growth on DMF was accompanied with ammonia release and the total organic carbon (TOC) analysis indicated its extensive mineralization. Batch culture studies were conducted in the substrate range of 100-5000 mg L−1 to determine the biokinetic constants. Strain Paracoccus sp. DMF could tolerate very high concentrations of DMF as the growth was observed even at 15 000 mg L−1. High (μmax) and (Ki) showed the suitability of the strain for the treatment of DMF containing waste water. Transient accumulation of dimethylamine (DMA) in the medium during the growth on DMF and utilization of DMA and monomethylamine (MMA) as growth substrates by Paracoccus sp. strain DMF showed that the pathway of DMF degradation involves DMA and MMA as intermediates, ultimately leading to the formation of carbon dioxide (CO2) and ammonia (NH3).