Aerobic Degradation of Chlorobenzene by Acinetobacter calcoaceticus Isolated from Polluted Water Body

摘要

A chlorobenzene(CB)-degrading bacterium was isolated by enrichment technique from chlorobenzene-contaminated water body. It was classified and identified as Acinetobacter calcoaceticus CB001 by phylogenetic analysis based on 16S rDNA sequence, in addition to biochemical and physiological characteristics. Resting cells were able to degrade CB from culture fluids with the concomitant release of chloride ion. The ranges of pH values and temperatures for good degradation of CB by strain CB001 cells were from 7.0 to 8.0 and 25 to 30°C, respectively. First order kinetics could be fitted to the biodegradation of CB after lag phase at initial concentrations of 20, 50, 80, and 120 mg·L-1. 80 mg·L-1 is the most suitable concentration for strain CB001 to degrade CB with the first order rate constant of 0.0376 h-1. Strain CB001 also showed capacity to degrade 1, 2-dichlorobenznene, 1, 3-dichlorobenznene, 1, 4-dichlorobenznene at solely initial concentration of 50 mg·L-1, but failed to degrade hexachlorobenzene. Results from this study could be helpful in the optimization of its use in bioremediation of CB.