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- Biodegradation of fluoroanilines by the wild strain Labrys portucalensisPublication . Amorim, Catarina L.; Carvalho, Maria F.; Afonso, Carlos M. M.; Castro, Paula M. L.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.
- Studies on the biodegradation of fluoroanilines by a single microorganismPublication . Amorim, Catarina L.; Carvalho, Maria F.; Afonso, Carlos M. M.; Castro, Paula M. L.Aromatic amines are considered important environmental pollutants due to their toxic and recalcitrant properties. The widespread use of these compounds in the industry and agriculture has led to their release to soils and waters. Microbial degradation has been found to be the major mechanism to avoid the accumulation of these pollutants in the environment. Literature studies on the biodegradation of halogenated anilines have mostly focused on chlorinated anilines and very little is known about utilization of fluorinated derivatives. This study focuses on the biodegradation of 2-, 3- and 4-fluoroaniline by a microbial strain (strain F11) identified as Labrys portucalensis. This microorganism has the capacity to degrade aerobically fluorobenzene as sole carbon and energy source. Non-induced cells and cells induced in fluorobenzene were used to examine the capacity of the degrading strain to metabolize the target compounds. Co-metabolic studies with fluorobenzene were also conducted. The experiments were run in batch mode at 25ºC with constant shaking. Growth, depletion of the target compounds and fluoride release were monitored. Strain F11 was capable to completely degrade 2-fluoroaniline. 3- and 4-fluoroaniline were degraded nearly to completion by F11 cultures induced with fluorobenzene and by cultures fed simultaneously with fluorobenzene. The fluoride liberation for those two fluorinated anilines occurred at different extents. C.L. Amorim and M.F. Carvalho wish to acknowledge a research grant from Fundação para a Ciência e Tecnologia (FCT), Portugal (Ref. SFRH/BD/47109/2008 and SFRH/BPD/44670/2008, respectively) and Fundo Social Europeu (III Quadro Comunitário de Apoio). This work was supported by the FCT Project - PTDC/BIO/67306/2006