PRODUCTION OF METHIONINE

PURPOSE:To efficiently recover methionine and KHCO3 by adding isopropyl alcohol to a filtrate discharged during the collection of methionine and saturating the solutions with a CO2 gas under cooling in the production of methionine from 5-(beta-methylmercaptoethyl)hydantion. CONSTITUTION:5-(beta-Methylmercaptoethyl)hydantion is hydrolyzed with potassium carbonate or potassium bicarbonate, then neutralized and crystallized under pressure of a carbon dioxide gas to separate and obtain methionine. A filtrate after separation and removal of methionine is blended with 0.5-2 pts.wt. based on 1 pt.wt. filtrate of isopropyl alcohol, saturated with a carbon dioxide gas under 0.5-20kg/cm G pressure to crystallize methionine and potassium bicarbonate, which are separated and recovered. In this method, advantageously methionine and potassium bicarbonate are readily recovered by preventing admixture of other impurities and colored substances without concentrating the filtrate. Methionine is useful as an additive for animal feed.