Mono-substituted phenol derivatives (cresol, aminophenol and hydroxybenzoic acid) were selected as model xenobiotic compounds in environment, and bioremoval kinetics of phenol derivative regioisomer by white rot fungi Coriolus hirsutus IFO 4917 in shaking flask were studied. As a result, the linear relation representing Hammett equation was confirmed in the plot of the removal rate constants of m- and p-mono-substituted phenol derivatives and the substituent constant (sigma) of Hammett equation. The plot showed a negative slope. A mathematical model to estimate the biodegradation rates of the m- and p-mono-substituted phenol derivatives was formulated.