| abstract |
Compositions and methods for the production of L-glufosinate are provided. The method involves converting racemic glufosinate to the L-glufosinate enantiomer or converting PRO to L-glufosinate in an efficient manner. In particular, the method involves the specific amination of PRO to L-glufosinate, using L-glutamate, racemic glutamate, or another amine source as an amine donor. PRO can be obtained by the oxidative deamination of D-glufosinate to PRO (2- oxo-4-(hydroxy(methyl)phosphinoyl)butyric acid) or generated via chemical synthesis. PRO is then converted to L-glufosinate using a transaminase in the presence of an amine donor. When the amine donor donates an amine to PRO, L-glufosinate and a reaction by product are formed. Because the PRO remaining represents a yield loss of L-glufosinate, it is desirable to minimize the amount of PRO remaining in the reaction mixture. Degradation, other chemical modification, extraction, sequestration, binding, or other methods to reduce the effective concentration of the by-product, i.e., the corresponding alpha ketoacid or ketone to the chosen amine donor will shift the reaction equilibrium toward L-glufosinate, thereby reducing the amount of PRO and increasing the yield of L-glufosinate. Therefore, the methods described herein involve the conversion or elimination of the alpha ketoacid or ketone by-product to another product to shift the equilibrium towards L-glufosinate. |