ENZYMATIC PRODUCTION OF D-BETA-ACETYLTHIOISOBUTYRIC ACID FROM METHYL DL-BETA-ACETYLTHIOISOBUTYRATE .4. PROCESS CONDITIONS FOR PRODUCTION OFD-BETA-ACETYLTHIOISOBUTYRIC ACID FROM METHYL DL-BETA-ACETYLTHIOISOBUTYRATE WITH THE CELLS OF PSEUDOMONAS-PUTIDA MR-2068

The process conditions concerned with the production of D-beta-acetylt hioisobutyric acid were investigated. Methyl DL-beta-acetylthioisobuty rate as an enzyme substrate was produced from methyl methacrylate in 9 6.6% yield by allowing 1.0 mol of methyl methacrylate to react with 1. 6 mol of thioacetic acid at 80-degrees-C for 6h. Through the study of hydrolytic reaction of methyl DL-beta-acetylthioisobutyrate with the c ells of Pseudomonas putida MR-2068, it was found that D-beta-acetylthi oisobutyric acid having more than 98% (e.e.) optical purity was obtain ed when the reaction was done below pH 7.5 and below 50-degrees-C. For example. 10% (w/v) methyl DL-beta-acetylthioisobutyrate in the reacti on mixture was asymmetrically hydrolyzed by 0.2% (w/v) cells at 45-deg rees-C at pH 7.0 for 18 h to give DAT having 98.2% (e.e.) optical puri ty in 49.7% yield. To prevent the decompositon and racemization of D-b eta-acetylthioisobutyric acid in the purification process, the use of a thin-film distillation apparatus for a continuous distillation was p roposed to be an effective purification method.