RESUMO
The study of bacterial degradation of 1-octylpyrrolidin-2-one (NOP) by river water and soil bacteria was the main aim of the research. Although the compound demonstrated bacteriostatic as well as bactericidal effects against Gram-positive and certain Gram-negative bacteria at concentrations ranging from 100 to 1000 mg L-1, its concentration of 100 mg L-1 was successfully degraded by microbial communities of both river water and alluvial soil; removal efficiencies reached 87.2 and 88.4% of dissolved organic carbon, respectively. Isolation of the strains responsible for the process showed that bacterial degradation was initiated by the octane-utilising bacteria of the genus Phenylobacterium, which used four carbon atoms of the NOP octyl chain and oxidised terminal carbon atom of the remaining chain. The structure of the intermediate produced by phenylobacteria was elucidated following the results obtained from the detailed electrospray mass spectrometry (ESI-MS) analysis; these experiments showed that it is a 4-(2-oxopyrrolidin-1-yl)butanoic acid. This intermediate was further degraded by other bacterial members of appropriate microbial communities, namely Bordetella petrii and Arthrobacter sp. Further tests proved that these bacteria were able to assimilate the nitrogen atom of the lactam ring and thus complete the degradation process.