| D-malate is becoming an important chiral compound which is a widely used as aversatile exploitation foreground in chiral pharmaceutical synthesis, chiral additivereagent and chiral accessory reagent. D-malate is studied in china only recently bymicrobiological resolution method, and the industrialized production has not beenreported. Therefore, the research on the production of D-malate using maleatehydratase is of important value both theoretically and economicly.Some innovations were obtained as follows:In the paper, the conversion of maleate to D-malate using maleate hydratase wasfirstly investigated. Fermentation conditions of strain Pimelobacter SimplexDM18(screened by He B-F.) was optimized and optimum medium obtained. Thebiomass(OD660) of fermentation culture broth achieved 4～4.5, more that of strainPseudomonas pseudoalcaligenes NCIMB9867 that was 0.8 by Mari?t J. van der Werf.Also it maleate hydratase activity was much higher than that of strain Arthrobacter spMCI2612 screened by Asano Y. and close to that of Arthrobacter pascens DMDC12screened by He B.-F.In the paper, Effects of malease activity and enzyme reaction condition werestudied to the dormancy cell of Pseudomonas pseudoalcaligenes NCIMB9867. Theeffects were: the permeabilized agent, reaction temperature, pH of reaction solution,substrate concentration and strain cell concentration. The optimum condition forenzyme reaction were obtained. In the course of the conversion form maleate tomalate in intermittently added with Na-maleate, the production concentration obtainedto 153.9g/L in 32 hours. The optical purity of the malate was 93.85 % ee.Transformatical rate was 96.67%, close to the highest level in the world.In the paper, the course of the conversion form maleate to malate that wassimultaneously reacted and separated was investiged. The production concentrationobtained 300g/L in 36 hours. The optical purity of the D-malate was 94.06%ee Thetransformatical rate closed to 99%. It overcome both substrate and product inhibition IIthat maleate converted D-malate in simultaneously reaction and separation, thattransformatical rate and production concentration was best in the world. |
