Isolation, identification and characterization of a novel Ralstonia sp. FD-1, capable of degrading 4-fluoroaniline.

A gram-negative strain, designated as FD-1, isolated from aerobic activated sludge was capable of metabolizing 4-fluoroaniline (4-FA) as its sole carbon and nitrogen source and energy supply. According to the Biolog GNIII detection method 17 of 71 carbon substrates were easily utilized, while 12 of 23 substrates did not inhibit strain FD-1. The 16S rDNA sequence from strain FD-1 was 99 % similar to Ralstonia sp., suggesting that it belonged to the genus Ralstonia. The optimal conditions for growth and 4-FA degradation were pH 7 and 30 °C. The tolerance to 4-FA were 1,250 mg/L, while the tolerance to salinity was 15 g/L. Catechol 2,3-dioxygenase activity was detected and degradation intermediates were analyzed by liquid chromatography mass spectrometry leading to a proposed degradation pathway and suggesting that extradiol cleavage was involved in 4-FA degradation. This is the first report on the degradation of 4-FA by a bacterium from the Ralstonia genus.

Characterization of residues from dismantled imported wastes.

Residues from the imported wastes dismantling process create a great burden on the ambient environment. To develop appropriate strategies for the disposal of such residues, their characteristics were studied through background value analysis and toxicity leaching tests. Our results showed that the heavy metals concentrations in residues were high, particularly those of Cu (7180 mg kg(-1)), Zn (2783 mg kg(-1)), and Pb (1954 mg kg(-1)). Toxicity leaching tests revealed a high metal releasing risk of such residues if they are disposed of in a landfill. However, the residues of imported wastes were also found to have some intrinsic metal recycling value.