Methods for the production of L-glufosinate (also known as phosphinothricin or (S)-2-amino-4-(hydroxy(methyl)phosphonoyl)butanoic acid) are provided. The methods comprise a two-step process. The first step involves the oxidative deamination of D-glufosinate to PPO (2-oxo-4-(hydroxy(methyl)phosphinoyl)butyric acid). The second step involves the specific amination of PPO to L-glufosinate, using an amine group from one or more amine donors. By combining these two reactions, the proportion of L-glufosinate in a mixture of L-glufosinate and D-glufosinate can be substantially increased.

A D-amino acid oxidase mutant with significantly improved catalytic performance, a gene encoding the gene, a vector containing the gene, a genetically engineered bacterium, and the application of the said mutant in the microbial catalytic preparation of L-ammonium glufosinate. The D-amino acid oxidase mutant was obtained from the amino acid shown in SEQ ID NO.1 by single-point mutation or multi-point combined mutation. The beneficial effects are mainly reflected in the following: the D-amino acid oxidase mutant with improved enzyme activity and thermal stability can be used in the microbial catalysed preparation of L-ammonium glufosinate, which is conducive to industrial production and has a better application prospect.

Methods for the production of L-glufosinate (also known as phosphinothricin or (S)-2-amino-4-(hydroxy(methyl)phosphonoyl)butanoic acid) are provided. The methods comprise a two-step process. The first step involves the oxidative deamination of D-glufosinate to PPO (2-oxo-4-(hydroxy(methyl)phosphinoyl)butyric acid). The second step involves the specific amination of PPO to L-glufosinate, using an amine group from one or more amine donors. By combining these two reactions, the proportion of L-glufosinate in a mixture of L-glufosinate and D-glufosinate can be substantially increased.

Methods for the production of L-glufosinate (also known as phosphinothricin or (S)-2-amino-4-(hydroxy(methyl)phosphonoyl)butanoic acid) are provided. The methods comprise a two-step process. The first step involves the oxidative deamination of D-glufosinate to PPO (2-oxo-4-(hydroxy(methyl)phosphinoyl)butyric acid). The second step involves the specific amination of PPO to L-glufosinate, using an amine group from one or more amine donors. By combining these two reactions, the proportion of L-glufosinate in a mixture of L-glufosinate and D-glufosinate can be substantially increased.

Methods for the production of L-glufosinate (also known as phosphinothricin or (S)-2-amino-4-(hydroxy(methyl)phosphonoyl)butanoic acid) are provided. The methods comprise a two-step process. The first step involves the oxidative deamination of D-glufosinate to PPO (2-oxo-4-(hydroxy(methyl)phosphinoyl)butyric acid). The second step involves the specific amination of PPO to L-glufosinate, using an amine group from one or more amine donors. By combining these two reactions, the proportion of L-glufosinate in a mixture of L-glufosinate and D-glufosinate can be substantially increased.

The present invention discloses a method for preparing L-glufosinate ammonium by biological enzymatic de-racemization, a glufosinate ammonium dehydrogenase mutant and a use thereof. The method for preparing L-glufosinate ammonium by biological enzymatic de-racemization includes catalyzing D,L-glufosinate ammonium as a raw material by a multi-enzyme catalysis system to obtain L-glufosinate ammonium. The enzyme catalysis system includes D-amino acid oxidase for catalyzing D-glufosinate ammonium in the D,L-glufosinate ammonium to 2-carbonyl-4-[hydroxy(methyl)phosphonyl]butanoic acid, and a glufosinate ammonium dehydrogenase mutant for catalytically reducing 2-carbonyl-4-[hydroxy(methyl)phosphonyl]butanoic acid to L-glufosinate ammonium. The glufosinate ammonium dehydrogenase mutant is obtained by mutation of glufosinate-ammonium dehydrogenase in wild fungi Thiopseudomonas denitrificans at a mutation site of V377S. The glufosinate ammonium dehydrogenase mutant in the present invention has better catalytic efficiency. When racemic D, L-glufosinate ammonium is used as a substrate for a catalytic reaction, the conversion rate is much higher than the conversion rate of a wild-type enzyme, and the yield of 2-carbonyl-4-[hydroxy(methyl)phosphonyl]butanoic acid (PPO for short) is also greatly improved.

Compositions and methods for the production of L-glufosinate are provided. The method involves converting racemic glufosinate to the L-glufosinate enantiomer or converting PPO to L-glufosinate in an efficient manner. In particular, the method involves the specific amination of PPO to L-glufosinate, using L-glutamate, racemic glutamate, or another amine source as an amine donor. PPO 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. PPO is then converted to L-glufosinate using a transaminase in the presence of an amine donor. When the amine donor donates an amine to PPO. L-glufosinate and a reaction by product are formed. Because the PPO remaining represents a yield loss of L-glufosinate, it is desirable to minimize the amount of PPO 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 PPO 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.