METHOD FOR PRODUCING ORGANIC ACID

A NOVEL METHOD IS PROVIDED WHEREBY A FREE ORGANIC ACID CAN BE PRODUCED PARTICULARLY FORM AN AMMONIUM SALT OF AN ORGANIC ACID HAVING A HIGH MELTING POINT OBTAINABLE BY BIOCONVERSION OF A CARBON SOURCE IN THE PRESENCE OF A NEUTRALIZING AGENT, EFFICIENTLY AT A LOW COST, AND THE USED MATERIAL FOR REACTION AND A BYPRODUCT CAN BE RECYCLED FOR REUSE WITHOUT BEING DISPOSED.@ AN AMMONIUM SALT OF ORGANIC ACID A SUCH AS A DICARBOXYLIC ACID,A TRICARBOXYLIC ACID OR AN AMINO ACID IS SUBJECTED TO REACTIVE CRYSTALLIZATION BY MEANS OF ACID B SUCH AS A MONOCARBOXYLIC ACID SATISFYING THE FOLLOWING FORMULA (1), TO SEPARATE FREE ORGANIC ACID A IN SOLID FORM:@ pKA (A) < pKA (B) (1)WHERE pKA (A) AND pKA (B) REPRESENT IONIZATION INDICES OF ORGANIC ACID A AND ACID B, RESPECTIVELY, PROVIDED THAT WHEN THEY HAVE PLURAL VALUES, THEY REPRESENT THE MINIMUM pKA AMONG THEM.@ THE CRYSTALLIZATION MOTHER LIQUOR AFTER PRECIPITATING AND SEPARATING ORGANIC ACID A IS , AFTER SEPARATING ACID B AND THEN AN AMMONIUM SALT OF ACID B, RECYCLED FOR USE IN THE REACTIVE CRYSTALLIZATION STEP. THE AMMONIUM SALT OF ACID B IS DECOMPOSED INTO ACID B AND AMMONIA, WHICH ARE RECYCLED FOR USE IN THE REACTIVE CRYSTALLIZATION STEP AND AS A NEUTRALIZING AGENT IN THE BIOCONVERSION STEP, RESPECTIVELY.FIGURE 1