Biodegradation of fluoroanilines by the wild strain Labrys portucalensis

Abstract

Aniline and halogenated anilines are known as widespread environmental toxic pollutants released into soil and water. In contrast to aniline, which is rapidly metabolized via catechol, halosubstituted anilines are more resistant to microbial attack. A fluorobenzene-degrading bacterium, Labrys portucalensis strain F11, was tested under different culture conditions for the degradation potential towards 2-, 3- and 4-fluoroaniline (2-, 3- and 4-FA). Strain F11 was able to use FAs as a source of carbon and nitrogen however, supplementation with a nitrogen source improved substrate consumption and its dehalogenation extent. When F11 cells were previously grown on fluorobenzene (FB), higher biodegradation rates were achieved for all isomers. Complete 2-FA biodegradation with stoichiometric fluoride release was achieved when FB-induced cells were used. On the other hand, the degradation of 3- and 4-FA was characterized by incomplete defluorination of the target compounds suggesting accumulation of fluorinated intermediates. F11 cultures simultaneously supplied with FB and the fluorinated anilines showed a concomitant degradation of both substrates, suggesting co-metabolic biodegradation. To our knowledge, this is the first time that biodegradation of 2- and 3-FA as a sole carbon and nitrogen source and co-metabolic degradation of FA isomers in the presence of a structural analogous compound is reported.