PRODUCTION OF D-VALINE AND L-VALINE FROM ISOPROPYL HYDANTOIN

摘要

PURPOSE:To produce high-purity D-valine and L-valine, by hydrolyzing isopropyl hydantoin with an alkali, and subjecting the reaction liquid containing DL-valine to a specific treatment. CONSTITUTION:Isopropyl hydantoin is mixed with an alkali and water, and hydrolyzed at =100 deg.C. The obtained reaction liquid containing DL-valine is acetylated with acetic anhydride at 20-30 deg.C, and N-acetyl-DL-valine is precipitated from the mixture with an acid. The N-acetyl-DL-valine is dissolved in water at a concentration of 5-40wt%, added with aminoacylase to effect the exclusive hydrolysis of the acetyl group of the N-acetyl-L-valine and obtain an acylase reaction liquid containing N-acetyl-D-valine and L-valine. The reaction liquid is adjusted to =1pH with an acid to effect the crystallization of N-acetyl-D- valine, which is separated by solid-liquid separation process and hydrolyzed with an acid to obtain D-valine. The acidic filtrate is made to contact with a strongly acidic ion exchange resin to effect the adsorption of L-valine, and the adsorbed L-valine is eluted.