A method of producing an amide from the corresponding nitrile comprising the following steps, i) providing a microorganism capable of producing a nitrile hydratase biocatalyst, ii) culturing the microorganism in a growth medium, iii) storing the microorganism, iv) contacting the nitrile by the microorganism in an aqueous medium and thereby converting the nitrile to the amide, wherein the microorganism is stored as none actively growing free cells in a storage medium that comprises water. The stored microorganism may be as whole microbial cells, this may be in the form of a cell paste recovered from a fermentation medium; an aqueous suspension of the microbial cells, prepared using a suitable suspending medium such as water, physiological saline solution, or a suitable buffer solution, such as phosphate or comprises the fermentation broth that contains components of the fermentation culture medium and products of microbial culture. The microorganism exhibits no significant loss of activity, for example if stored even for at least 2 days, especially 3 to 28 days.