| Abstract: | ![]()
A total of 106 strains of nocardioform bacteria were chosen from the IMET Culture Collection and checked for their ability to degrade aniline. Among them only four Rhodococcus strains proved to be capable of removing aniline from a liquid mineral salts medium devoid of any other carbon and nitrogen source. This capability was found to be due to total degradation of the aromatic substrate via the β-ketoadipate pathway which is initiated by the action of inducible oxygenating enzymes. Without any exception, the ring-cleaving enzymes induced during cell precultivation with aniline were pyrocatechases of the “ordinary” type. None of the four aniline-assimilating Rhodococcus strains could utilize any of the monochloroaniline isomers as the sole carbon and energy source for growth. However, resting aniline-grown cells of these strains mediated the turnover of 2- and 3-chloroaniline in the presence of chloramphenicol. The respective rates were substantially higher (31 to 59% as compared with the unsubstituted aniline) when glucose was provided as the additional carbon substrate. In contrast, 4-chloroaniline turnover occurred with low rates (3–6%), even in the presence of glucose. With all of the four Rhodococcus strains under study, 3-chloroaniline turnover resulted in chloride levels which corresponded to an almost stoichiometric dechlorination of the substrate. 2-Chloroaniline, however was only partially dechlorinated even in the presence of glucose indicating that certain chlorinated metabolite(s) was (were) accumulated in the respective incubation media. |
