European Journal of Biomedical and Pharmaceutical Sciences

GROWTH KINETICS AND BIODEGRADATION OF HIGH INHIBITORY CONCENTRATION OF PHENOL, CATECHOL AND 2,4-DICHLOROPHENOL BY TRAMETES VERSICOLOR 1

I. Stoilova, V. Stanchev, G. Dimitrova, G. Angelova* and A. Krastanov

ABSTRACT

Biodegradation of high concentration of phenol (1g/l), catechol (2 g/l) and 2,4-dichlorophenol (2g/l) by Trametes versicolor is studied. Modified kinetic model of Verhulst/Aiba/Andrews is fitted to describe the specific growth rate at inhibitory growth type. When catechol is used as carbon source the microbial culture shows highest specific growth rate (μmax 0.0263 h-1) which correlates with zero cell death rate, (β). The value of Ks (Ks 1.360 g/l) demonstrates that T. versicolor has the lowest catechol affinity compared with phenol (Ks 1.064g/ l) and 2,4 dichorphenol (Ks 0.953 g/l). The value of Ki is the lowest for catechol degradation which correspond to high inhibition effect than phenol and 2,4-dichorphenol. The lowest specific growth rate (μmax) and the highest cell death rate (β) are observed at 2,4-dichorphenol as a sole carbon source. The successful degradation of studied phenolics compounds is found to be dependant on the enzymes from β-ketoadipate pathway- phenol hydroxylase and catechol 1,2-oxygenase enzymes and the enzyme laccase. Catechol is determined as a best inductor for synthesis of phenol hydroxylase (0,4 U/mg), catechol 1,2-oxygenase (0.22 U/mg) and laccase (1344 U/ml).

Keywords: Trametes versicolor, biodegradation, phenol, catechol, 2,4-dichlorophenol, phenol hydroxylase, 1,2-oxygenase, laccase.