Process for the enzymatic production of carnitine from beta-lactones
Subject of the invention is a process for the production of L-carnitine, wherein a β-lactone, which is a 4-(halomethyl)oxetane-2-one, is converted into L-carnitine, wherein the process comprises an enzymatic conversion of the β-lactone into (R)-4-halo-3-hydroxybutyric acid or (R)-4-halo-3-hydroxybutyric acid ester.
1. A process for the production of L-carnitine, wherein a β-lactone, which is a 4-(halomethyl)oxetane-2-one, is converted into L-carnitine, wherein the process comprises enzymatic conversion of the β-lactone into (R)-4-halo-3-hydroxybutyric acid, wherein the enzymatic conversion is carried out with a lipase in an aqueous medium, the lipase having the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2, wherein the enantiomeric purity of the (R)-4-halo-3-hydroxybutyric acid is at least 95% e.e., and conversion of (R)-4-halo-3-hydroxybutyric acid into L-carnitine with trimetylamine.
2. The process of claim 1 , wherein the β-lactone is a racemate.
3. The process of claim 2 , wherein an enantiomeric excess of the (R)-4-halo-3-hydroxybutyric acid is obtained.
4. The process of claim 1 , wherein the enzymatic conversion is carried out in a two phase solution, wherein (R)-4-halo-3-hydroxybutyric acid is enriched in the aqueous phase.
5. The process of claim 1 , wherein after enzymatic conversion, residual β-lactone is removed from the solution.
6. The process of claim 5 , wherein the residual β-lactone is removed by extraction with a solvent.
7. The process of claim 1 , wherein the lipase is from Candida, Pseudomonas, Aspergillus, Bacillus or Thermomyces.
8. The process of claim 1 , wherein the lipase is from Pseudomonas cepacia, Pseudomonas fluorescens , or Candida antarctica.
9. The process of claim 1 , wherein the enzymatic conversion is carried out at a temperature between 0° C. and 50° C., and/or wherein the enzymatic conversion is carried out in an aqueous solution comprising 0.1 to 10 weight % β-lactone.
10. The process of claim 9 , wherein the enzymatic conversion is carried out at a temperature between 20° C. and 40° C., and/or wherein the enzymatic conversion is carried out in aqueous solution comprising 0.1 to 10 weight % β-lactone.
11. The process of claim 1 , in which the β-lactone is synthesized in a preceding step in a [2+2] cycloaddition of ketene and an aldehyde of the formula X-CH2-CHO, wherein x is selected from Cl, Br and I.
12. The process of claim 1 , wherein the total yield of (R)-4-halo-3-hydroxybutyric acid in the enzymatic conversion is between 40% and 50%, based on the total initial amount of β-lactone.
13. The process of claim 1 , wherein the reaction time of the enzymatic conversion of the β-lactone into (R)-4-halo-3-hydroxybutyric acid is less than 10 hours.