Research article - Peer-reviewed, 2008
Degradation of mixtures of phenolic compounds by Arthrobacter chlorophenolicus A6Unell, Maria; Nordin, Karolina; Jernberg, Cecilia; Stenstrom, John; Jansson, Janet K.
AbstractIn this study the chlorophenol-degrading actinobacterium, Arthrobacter chlorophenolicus A6, was tested for its ability to grow on mixtures of phenolic compounds. During the experiments depletion of the compounds was monitored, as were cell growth and activity. Activity assays were based on bioluminescence output from a luciferase-tagged strain. When the cells were grown on a mixture of 4-chlorophenol, 4-nitrophenol and phenol, 4-chlorophenol degradation apparently was delayed until 4-nitrophenol was almost completely depleted. Phenol was degraded more slowly than the other compounds and not until 4-nitrophenol and 4-chlorophenol were depleted, despite this being the least toxic compound of the three. A similar order of degradation was observed in non-sterile soil slurries inoculated with A. chlorophenolicus. The kinetics of degradation of the substituted phenols suggest that the preferential order of their depletion could be due to their respective pKa values and that the dissociated phenolate ions are the substrates. A mutant strain (T99), with a disrupted hydroxyquinol dioxygenase gene in the previously described 4-chlorophenol degradation gene cluster, was also studied for its ability to grow on the different phenols. The mutant strain was able to grow on phenol, but not on either of the substituted phenols, suggesting a different catabolic pathway for the degradation of phenol by this microorganism.
KeywordsArthrobacter chlorophenolicus; bioremediation; 4-bromophenol; 4-chlorophenol; mixed substrates; 4-nitrophenol
2008, volume: 19, number: 4, pages: 495-505
UKÄ Subject classification
Environmental Sciences related to Agriculture and Land-use
URI (permanent link to this page)