Minimization of by-product formation during D-amino acid oxidase catalyzed racemate resolution of D/L-amino acids
- Publication Type
- Journal contribution (peer reviewed)
- Authors
- Trost, E.-M., Fischer, L.
- Year of publication
- 2002
- Published in
- Journal of Molecular Catalysis B: Enzymatic
- Band/Volume
- 19-20/
- DOI
- 10.1016/S1381-1177(02)00166-2
- Page (from - to)
- 189-195
D-Amino acid oxidase (DAAO, EC 1.4.3.3) was applied to biotransformations of D-methionine or D-phenylalanine to the corresponding a-keto acids starting with the racemic mixts. as substrates. Hydrogen peroxide is formed as byproduct in the DAAO-catalyzed reaction. This reactive species is disadvantageous for the racemate resoln. process due to the chem. decarboxylation of the a-keto acids as well as the inactivation of the DAAO. To immediately remove the generated H2O2 during the biotransformations three different com. available catalases (bovine liver, Aspergillus niger or Micrococcus lysodeikticus) were tested. By external addn. of catalase from Micrococcus lysodeikticus an a-keto acid yield of 100% was obtained after complete conversion of the D-phenylalanine. The space-time yield of the a-keto acid prodn. increased up to 8.26 g l-1 h-1 compared to the process without addn. of catalase (0.14 g l-1 h-1). Another observation was a relationship between D-redox potential and H2O2 concn. which should be the basis for an automated catalase feeding in the amino acid resoln. process using DAAO in the future.