Trichosporon cutaneum R57 is known as effective biodegradant able to utilize and thus remove a number of toxic aromatic compounds from the environment. In the present study, the dynamics of the processes of degradation of monohydoxyl derivatives of phenol (resorcinol, catechol and hydroquinone) in concentrations up to 1.6g/l were investigated and inhibitory constants (k i ) of these compounds were determined 0.58, 0.55, and 0.6g/l correspondingly. The biodegradation of significantly more toxic aromatic compounds 2,6-dinitrophenol (k i =0.13g/l), α-methylstyrene (k i =0.25g/l) and acetophenone (k i =0.15g/l) was also described. Based on summarized qualitative and quantitative data and the “if-then” rules developed, a fuzzy model was designed to describe the processes despite the degree of toxicity and concentration of the aromatic compounds. The output linguistic variables “normal”, “check” and “attention” were defined, which determine further measures for improvement of process quality. The model suggested provides opportunity for early estimation of the biodegradation process quality.