L-Glufosinate Production via PPO Transamination Equilibrium Shifting
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Solution Overview
Problem
Current methods for producing L-glufosinate yield a racemic mixture, and cost-effective high-yield production of the more potent L-glufosinate form is not available.
Innovation Solution
A three-step process involving oxidative deamination of D-glufosinate to PPO, followed by amination to L-glufosinate using a transaminase, and reduction of alpha ketoacid by-products with enzymes or chemical means to shift the reaction equilibrium towards L-glufosinate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If racemic glufosinate is produced using current commercial chemical synthesis methods, then production cost is reduced, but the yield of the more potent L-glufosinate form is low because a racemic mixture of D- and L-glufosinate is obtained
Solution Approach 1:
The patent segments the production process into distinct steps: (1) oxidative deamination of D-glufosinate to PPO using D-amino acid oxidase, and (2) amination of PPO to L-glufosinate using transaminase. This segmentation allows selective production of L-glufosinate from the racemic mixture, improving enantiomeric purity while maintaining cost-effectiveness through enzymatic catalysis.
Solution Approach 2:
The patent uses PPO (2-oxo-4-(hydroxy (methyl) phosphinoyl) butyric acid) as an intermediary compound. D-glufosinate is first converted to PPO, which then serves as the substrate for transaminase to produce L-glufosinate. This intermediary approach enables enantioselective production while avoiding direct resolution of the racemic mixture.
2Productivity
If the transamination reaction is allowed to reach equilibrium, then the reaction proceeds to completion, but PPO remains in the mixture representing yield loss
Solution Approach 1:
The patent converts the harmful effect of by-product accumulation (which limits equilibrium conversion) into a benefit by using ketoglutarate decarboxylase to transform α-ketoglutarate into succinic semialdehyde. This enzymatic conversion removes the by-product that would otherwise inhibit complete transamination, allowing the reaction to proceed to full conversion and eliminate PPO from the mixture.
Solution Approach 2:
The patent implements a continuous useful action by coupling the transamination reaction with the decarboxylation of α-ketoglutarate. As the transaminase produces L-glufosinate and α-ketoglutarate, the ketoglutarate decarboxylase immediately converts the α-ketoglutarate to succinic semialdehyde, maintaining the reaction drive and preventing equilibrium limitation. This continuous removal of by-product ensures complete conversion of PPO to L-glufosinate.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Increases the yield and simplifies the isolation of L-glufosinate by minimizing by-products, allowing for higher concentrations of L-glufosinate in the reaction mixture.
Implementation Method 1
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.
Implementation Method 2
For example, when L-glutamate is used as the amine donor, the KG by-product can be converted to succinic semialdehyde (SSA) by the addition of a ketoglutarate decarboxylase (KGD) to the reaction.
Implementation Method 3
PPO can be obtained by the oxidative deamination of D-glufosinate to PPO
Data Source
AI summary
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.