In a process for biological production of an amide wherein a nitrile is hydrated into a corresponding amide by the action of a nitrile hydratase originated in a microorganism, the improvement which comprises the use of nitrile hydratase which is obtained by culturing a microorganism of the species Rhodococcus rhodochrous in the presence of a cobalt ion. Aromatic nitriles such as a cyanopyridine as well as aliphatic nitrile such as acrylonitrile are hydrated into the corresponding amides.
