NOVEL OPTICAL RESOLUTION OF PHENYLALANINE RACEMATE UTILIZING ENZYME REACTION AND MEMBRANE EXTRACTION

A novel optical resolution method for D,L-phenylalanine in which an en zyme reaction and a membrane extraction are combined has been designed . In the first stage only the L-isomer of the racemic phenylalanine me thyl ester was selectively hydrolyzed by the enzyme alpha-chymotrypsin . Further, the unreacted ester was selectively recovered from the mixt ure of the transferred amino acid and the ester form by a membrane ext ractor. Effects of operation conditions in the enzyme reaction and the membrane extraction on the separation efficiency were investigated. T he pH in the material sources is found to be an important factor in th e activity and selectivity for the enzymatic resolution. A novel immob ilized enzyme enables the expensive enzyme to be reused in the feed so lutions. The hollow-fiber membrane extractor was a good separator for an amino acid and its ester derivative, because only the ester was sel ectively extracted into an organic phase. The novel separation system becomes a very useful process for the optical resolution of amino acid s by combining the enzyme reaction with a membrane extraction.