Abstract: A process for producing an amide compound is described, wherein from a nitrile compound, the corresponding amide compound is produced by the action of nitrile hydratase, characterized in that the hydrocyanic acid concentration in a composition containing the nitrile compound is reduced by a chemical process, and thereafter nitrile hydratase acts on the nitrile compound. According to the invention, the decrease of the activity of the enzyme nitrile hydratase can be effectively suppressed so that an amide compound can be effectively produced from a nitrile compound.

Abstract: A method for purifying a nitrile which comprises contacting a nitrile containing an aldehyde with a cation exchange resin carrying a polyamine to remove the aldehyde from the nitrile. The ion exchange resin can be regenerated and reused repeatedly.

Abstract: Cells having enzyme activity, and the enzyme activity thereof, are preserved for a prolonged period of time, as a suspension of microbial cells or as a suspension of immobilized cells in particles, in an aqueous medium that is a neutral or weakly basic aqueous solution of inorganic salts, having a molarity ranging from 100 mM to the saturation concentration of the inorganic salts. Preferably, the microbial cells are cells containing the enzyme, nitrile hydratase or nitrilase, such as Gordona terrae or Rhodococcus rhodochrous, and the inorganic salts are phosphates, borates, sulfates, sulfites or hydrochlorides. The present invention provides an industrially useful method for preserving a large quantity of cells or immobilized cells in particles having nitrile hydratase or nitrilase enzyme activity for a prolonged period of time (e.g., 300 days) without cell lysis or enzyme deterioration even at room temperature.