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.
1. An isolated microorganism which is Rhodococcus rhodochrous strain NCIMB 41164.
2. A method of culturing the microorganism Rhodococcus rhodochrous strain NCIMB 41164 in a culture medium that contains urea or a derivative of urea.
3. A method according to claim 2 in which urea or urea derivative is introduced into the culture medium at least six hours after the start of growth of the microorganism.
4. A method according to claim 2 in which the culture medium contains less than 0.2 g/l urea or the urea derivative for at least the first 6 hours of culturing the microorganism and thereafter urea or the urea derivative is added to the culture medium.
5. A method according to claim 2 in which the culture medium contains less than 0.2 g/l urea or the urea derivative for at least the first 12 hours of culturing the microorganism and thereafter urea or the urea derivative is added to the culture medium.
6. A method according to claim 2 in which urea or the urea derivative is added to the culture medium within 48 hours of culturing.
7. A method of improving the biocatalytic activity of a microorganism according to claim 1 , in which the microorganism is cultured in a culture medium that comprises urea or a derivative of urea,
wherein urea or the derivative of urea is introduced into the culture medium at least 6 hours after the start of growth of the microorganism.
8. A method according to claim 7 in which the culture medium contains less than 0.2 g/l urea or the derivative of urea for at least the first 6 hours of culturing the microorganism and thereafter urea or the derivative of urea is added to the culture medium.
9. A method according to claim 7 in which the culture medium contains less than 0.2 g/l urea or the derivative of urea for at least the first 12 hours of culturing the microorganism and thereafter urea or the derivative of urea is added to the culture medium.
10. A method according to claim 7 in which urea or the urea derivative is added to the culture medium within 48 hours of culturing.
11. An aqueous composition comprising a biocatalyst that is the microorganism Rhodococcus rhodochrous strain NCIMB 41164 and wherein the biocatalyst is in the form of a non-actively growing free cell microorganism.