Coupled Reactor Filled With Immobilized Aminoacylase And Production Of High Purity D-methionine

The coupled reator (BSTR and PBR) was used to optical resolution of N-Ac-DL-Methionine. BSTR was filled with immobilized Aspergillus oryzae pellets, while PBR was filled with immobilized aminoacylase. The fluid was first treated by immobilized Aspergillus oryzae pellets, and then the enzymatic deacylation was treated by immobilized aminoacylase with high rate of conversion.And a simple and effective technique for obtaining D-Methionine with high purity from N-acetyl-D-Methionine by ion-exchange is presented.The immobilization of aminoacylase was performed via diethylaminoethyl divinyl benzene (DEAE-D/H) .The result showed that DEAE-D/H-8 was selected as the best immobilization carrier, while the specific activity was up to 1340-1420U/g, while the activity yield was about 39%.Via the analyse of carriers'structure,it maintained macroporous after immobilization.The effect performed excellent,when the surface was large.The coupled reator filled with immobilized aminoacylase and immobilized Aspergillus oryzae was presented.When the resolution rate of substrate was 75% in the reactor of immobilized Aspergillus oryzae after 32 hours,the mixture was further enzymatically deacylated by the immobilized aminoacylase. The height of the immobilized aminoacylase reactor was 25cm.The resolution rate was as high as 99%, when the velocity of flow was below 1.18m/h.Esolution of N-Ac-DL-Methionine was carried out in batch reactor; the reaction time of specific conversation can be calculated by the model which was put forward in the paper. Then the furthure resolution of enzymation deacylation was carried out in continuous reactor (packed bed reactor). A one-dimension axial diffusion model of reactor was put forward. Based on the model, the predict result coincide well with the experiment data.The N-acetyl-D-Methionine purified from the mixture of enzymatically deacylated N-acetyl-DL-Methionine was hydrolyzed in the condition of hydrochloric acid. The deacylation rate was 97.87%. D-Methionine was successfully separated and purified from the hydrolysate by macroporous cationic ion-exchange column.The relationship between pH and D-Methioine concentration was investigated and the break through facter and exchange zone height was obtainde. Experimental results indicated that, the purity and yield of D-Methioine can reach as high as 99.749% and 88.96%,respectively.The high purity DL-Phenylalanine was produced in the similar conditions as D-Methionine.The break through and elution curves were investigated in the ion-exchange process.The relationship between pH and DL-Phe concentration was obtained, and the operating temperature was 70℃in the elution process. The purity and yield of DL-Phe can reach as high as 99.659% and 88.56%,respectively..