L-Glufosinate Enzymatic Conversion for Stereoisomer Purity
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Solution Overview
Problem
Current commercial methods for producing glufosinate yield a racemic mixture of L- and D-glufosinate, with L-glufosinate being more potent, and there is a need for cost-effective methods to produce pure L-glufosinate or a mixture enriched for L-glufosinate.
Innovation Solution
A two-step process involving oxidative deamination of D-glufosinate to PPO using a mutant D-amino acid oxidase enzyme, followed by amination of PPO to L-glufosinate with a transaminase enzyme, utilizing amine donors, to achieve a substantial conversion of D-glufosinate to L-glufosinate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current commercial chemical synthesis methods are used, then glufosinate can be produced, but only a racemic mixture of L- and D-glufosinate is obtained with reduced potency
Solution Approach 1:
The synthesis process is divided into distinct enzymatic steps: first oxidative deamination of D-glufosinate to PPO using DAAO, then amination of PPO to L-glufosinate using transaminase. This segmentation allows each step to be optimized for stereoselectivity, achieving high L-glufosinate purity through controlled sequential transformations rather than attempting single-step synthesis.
Solution Approach 2:
PPO (2-oxo-4-(hydroxy(methyl)phosphinoyl)butyric acid) serves as an intermediary compound in the synthesis pathway. The DAAO enzyme mediates the conversion of D-glufosinate to PPO, and the transaminase mediates the conversion of PPO to L-glufosinate. This intermediary approach enables stereoselective transformation through enzyme-catalyzed steps that would be difficult to achieve through direct chemical synthesis.
2Manufacturing precision
If enzymatic methods with mutant DAAO are used, then L-glufosinate can be produced with high stereoselectivity, but enzyme development and optimization are required
Solution Approach 1:
The DAAO enzyme has been mutated to alter its kinetic parameters, specifically achieving an increased activity of about 3 µmol/min*mg or greater. The mutant DAAO comprises specific amino acid substitutions (F58K and M213S or N54V, F58Q, and M213S) that change the enzyme's catalytic efficiency and substrate specificity, enabling it to effectively drive the oxidative deamination reaction for high L-glufosinate production.
3Productivity
If amine donors are used in the amination step, then L-glufosinate can be produced efficiently, but unreacted amine donor requires separation or reuse
Solution Approach 1:
The patent addresses the handling of unreacted amine donor by providing options to either separate and recover it from the reaction mixture or reuse it in further rounds of reaction. This approach maximizes the utility of the amine donor substrate, reducing waste and improving the overall economics of the process by maintaining high conversion efficiency while minimizing material loss.
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
The method enables the production of a composition predominantly comprising L-glufosinate, with at least 70% conversion efficiency, allowing for effective use as a herbicide with reduced amounts.
Implementation Method 1
The first step involves the oxidative deamination of D-glufosinate to PPO (2-oxo-4-(hydroxy(methyl)phosphinoyl)butyric acid)
Implementation Method 2
reacting D-glufosinate with a D-amino acid oxidase (DAAO) enzyme to form PPO
Implementation Method 3
the method involves reacting D-glufosinate with a D-amino acid oxidase (DAAO) enzyme to form PPO (2-oxo-4-(hydroxy(methyl)phosphinoyl)butyric acid); followed by aminating the PPO to L-glufosinate by a transaminase (TA) enzyme, using an amine group from one or more amine donors
Data Source
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AI summary
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.