| 摘要 |
PROBLEM TO BE SOLVED: To provide a new method whereby a free organic acid is efficiently and inexpensively produced from the ammonium salt of a high melting point organic acid obtained by microbiologically transforming a carbon source in the presence of a neutralizing agent and wherein used reaction raw materials and by-products are circulated and reused without being discarded. SOLUTION: This new method comprises reaction-crystallizing the ammonium salt of an organic acid A, e.g. a dicarboxylic acid, a tricarboxylic acid or an amino acid, by using an acid B such as a monocarboxylic acid satisfying the formula pKa(A)≤pKa(B) (wherein pKa(A) and pKa(B) are the ionization exponents of the organic acid A and the acid B, respectively, and when they have a plurality of values, pKa represents the lowest value among them) and separating the free organic acid A in a solid form. After precipitation and separation of the organic acid A, a crystallization mother liquid is circulated to and used for a reaction crystallization process after separation of the acid B and its ammonium salt. The ammonium salt is decomposed to the acid B and ammonia; the former is used for the reaction crystallization process and the latter is circulated to a microbial transformation process to be used as the neutralizing agent. COPYRIGHT: (C)2004,JPO&NCIPI
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