All of the enzymes relating to aniline degradation in C. acidovorans AN3 were inducible ones. When growing on aniline as sole carbon, nitrogen and energy sources, the cells of C. acidovorans AN3 contained aniline dioxygenase, catechol-2, 3-dioxygenase, 2-hydromuconic semialdehyde dehydrogenase, 4-oxalocrotonic acid decarboxylase and 4-hydroxy-2-oxovalerate acid aldolase. The Km and Vmax of aniline dioxygenase were 292 mumol/L and 3.57 mumol.mg-1. min-1, respectively. The Km and Vmax of catechol-2, 3-dioxygenase were 16.4 mumol/L and 15.2 mumol.mg-1.min-1, respectively. According to these results, the degradation metabolism pathway of aniline by C. acidovorans AN3 was hypothesised.