Glufosinate is a broad spectrum, amino acid herbicide that is an increasingly important tool for growers facing the challenges of weeds resistant to other herbicides. Currently marketed glufosinate products are racemic mixtures of the active L-glufosinate isomer and the inactive D-glufosinate isomer. It is estimated that in 2012, in the United States alone, more than 5 million pounds of non-herbicidal D-glufosinate were purchased and applied, representing a significant cost and environmental burden. This burden continues to increase as use of racemic glufosinate grows. AgriMetis has developed and patented a novel enzymatic process that converts D-glufosinate into L-glufosinate, resulting in an L-glufosinate product (Glu-L™) with an enantiomeric excess greater than 98%.<br/>In AgriMetis’ novel enzymatic approach, a D-amino acid oxidase (DAAO) is combined with a transaminase (TA) to perform deracemization of glufosinate. The first reaction, catalyzed by an evolved DAAO, specifically converts D-glufosinate to 4-(hydroxymethylphosphinyl)-2-oxobutanoic acid (PPO), an intermediate without chirality. The second reaction, catalyzed by a TA, specifically converts PPO to L-glufosinate. Both reactions can occur simultaneously, or in separate steps and reactors. The reactions occur under mild conditions, in aqueous solutions at moderate temperatures, and can reach completion within 10 hours. The enzymes are immobilized, which allows for their recovery and reuse in ten or more reactions. Product isolation from the completed reaction mass is also performed under mild conditions.  Data will be presented showing the improvements to the DAAO enzyme to improve its efficiency, optimization and consequences of enzyme immobilization, process conditions, and scale up of this technology to pilot scale. AgriMetis continues to drive its Glu-L technology toward commercialization so that it can deliver to growers a lower cost solution to herbicide-resistant weeds.

A novel enzymatic process to produce active L-glufosinate from inactive D-glufosinate

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.