Method for producing enationmerically pure d-ppt

Abstract

A method of producing enantimoerically pure D-Phosphinothricin (D-PPT) by providing a mixture of D and L PPT, N-acetylating L-PPT and then recovering and purifying D-PPT.

1 - 18 . (canceled) 
     
     
         19 . A method of producing enantiomerically pure D-Phosphinothricin (D-PPT), comprising the steps of:
 (a) providing cells which contain an enzyme capable of selectively N-acylating PPT;   (b) growing said cells in a medium which contains D-L PPT to produce conditioned medium;   (c) separating the cells from the conditioned medium of (b);   (d) optionally extracting the conditioned medium with a non-aqueous, non miscible solvent, at various pHs, so that the PPT containing fraction is separated from the fraction that contains molecules more water soluble than is PPT;   (e) optionally admixing with the conditioned or PPT-containing extracted media of step (d) a cation exchange resin in its protonated form, in an amount, and at pH, sufficient to absorb a substantial proportion of the cations—other than PTT, from the medium;   (f) admixing with the conditioned medium, extracted medium or medium to result from step (e) a cation exchange resin in its protonated form, in an amount, and at a pH, sufficient to bind the bulk of the PPT in the medium; and   (g) harvesting the cation ion exchange resin from step (f) to which the PPT is bound and selectively eluting PPT from it using an eluting medium having a sufficient pH and ionic strength, with the proviso that the pH of the said medium is not so low as to cause racemisation of the thus eluted PPT.   
     
     
         20 . The method according to  claim 19 , wherein D-PPT has an enantiomeric excess of at least 98.5%.