| 摘要 |
A stable composition containing 35 to 48% lysine sulphate for animal nutrition is prepared by culturing a lysine-producing microorganism in a culture medium and adding sulfuric acid or ammonium sulphate during culturing to convert lysine as it is formed to lysine sulphate. The culture medium contains ammonia and ammonium sulphate, and a carbon source selected from glucose, sucrose and starch hydrolyzates in an amount such that the total weight ratio of fermentable substances/solids is greater than 80%. The concentration of the carbon source is maintained at 5 to 15 g/liter and ammonia is added during culturing to maintain an ammonium ion concentration of 1 to 5 g/liter. After allowing concentration of the carbon source to fall to less than 2 g/liter, culturing is stopped and the resultant cultured medium is concentrated and dried. The composition has good stability in moist air and preferably has a microporosity of about 0.3 cm3/g and a surface area of about 0.5 m2/g.
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