A microorganism which is Rhodococcus rhodochrous strain NCIMB 41164 or a
mutant thereof. A method of culturing the microorganism in a culture
medium comprising urea or urea derivative is claimed. A nitrite hydratase
obtainable from the microorganism is claimed. Also claimed is a process
of preparing an amide from the corresponding nitrite wherein the nitrite
is subjected to a hydration reaction in an aqueous medium in the presence
of a biocatalyst selected from the group consisting of a microorganism
which is a Rhodococcus rhodochrous strain NUMB 41164, a mutant thereof
and a nitrite hydratase obtainable from Rhodococcus rhodochrous strain
NCIMB 41164 or a mutant thereof. Also claimed is a method of storing the
Rhodococcus rhodochrous NUMB 41164.