Diversity of 3-chloroaniline and 3,4-dichloroaniline degrading bacteria isolated from three different soils and involvement of their plasmids in chloroaniline degradation

Abstract

Attempts were made to isolate 3-chloroaniline (3-CA) and 3,4-dichloroaniline (3,4-DCA) degrading bacteria from the A- and B-horizon of three different soils. A variety of 3-CA degrading bacteria was obtained from all soils, whereas 3,4-DCA degrading strains were only isolated from one soil. Amongst the 3-CA and 3,4-DCA degraders, two belong to the gamma-Proteobacteria and seven to the beta-Proteobacteria. Of the latter group, five are members of the family of the Comamonadaceae. Interestingly, all isolates contained an IncP-1beta plasmid. These plasmids could be divided into four major groups based on restriction digest patterns. While all plasmids that were detected in the isolates, except one, encode total degradation of 3-CA, no indigenous plasmid that codes for total degradation of 3,4-DCA was found. This is the first study that reports the presence of diverse transferable plasmids that encode mineralisation of 3-CA in different 3-CA degrading species.