Immobilization of an amino acid racemase for application in crystallization‐based chiral resolutions of asparagine monohydrate. Issue 12 (28th August 2020)

• Record Type: Journal Article
• Authors: Carneiro, Thiane; Wrzosek, Katarzyna; Bettenbrock, Katja; Lorenz, Heike; Seidel‐Morgenstern, Andreas
• Is Part Of: Engineering in life sciences. Volume 20:Issue 12(2020)
• Page Start: 550
• Page End: 561
• Publication Date: 2020-08-28
• Subjects: amino acid racemase -- enzyme immobilization -- packed bed reactor -- racemization; Bioengineering -- Periodicals; 660.605
• DOI: 10.1002/elsc.202000029
• Languages: English
• ISSNs: 1618-0240

Abstract

Abstract: Integration of racemization and a resolution process is an attractive way to overcome yield limitations in the production of pure chiral molecules. Preferential crystallization and other crystallization‐based techniques usually produce low enantiomeric excess in solution, which is a constraint for coupling with racemization. We developed an enzymatic fixed bed reactor that can potentially overcome these unfavorable conditions and improve the overall yield of preferential crystallization. Enzyme immobilization strategies were investigated on covalent‐binding supports. The amino acid racemase immobilized in Purolite ECR 8309F with a load of 35 mg‐enzyme/g‐support showed highest specific activity (approx. 500 U/g‐support) and no loss in activity in reusability tests. Effects of substrate inhibition observed for the free enzyme were overcome after immobilization. A packed bed reactor with the immobilized racemase showed good performance in steady state operation processing low enantiomeric excess inlet. Kinetic parameters from batch reactor experiments can be successfully used for prediction of packed bed reactor performance. Full conversions could be achieved for residence times above 1.1 min. The results suggest the potential of the prepared racemase reactor to be combined with preferential crystallization to improve resolution of asparagine enantiomers.