(481b) Continuous Enzymatic Production of Enantiopure Amines in a Packed Bed Recycle Reactor

Continuous enzymatic
production of enantiopure amines in a packed bed recycle reactor

Robert D. Franklin‡,
Adam A. Caparco‡, Joshua A. Whitley‡, Bettina R.
Bommarius‡, Julie A. Champion‡, Andreas S. Bommarius‡#

‡School of
Chemical and Biomolecular Engineering, Georgia Institute of Technology,

Parker H. Petit
Institute for Bioengineering and Bioscience,

Engineered
Biosystems Building, 950 Atlantic Drive N.W., GA 30322, USA

#School of
Chemistry and Biochemistry, Georgia Institute of Technology,

950 Atlantic
Drive, Atlanta, GA 30332-2000, USA

Scalable manufacturing of chiral amines is of major
importance in the pharmaceutical industry. Biocatalytic production of these
compounds offers key advantages including high enantioselectivity, mild
operating conditions, and sustainable catalyst production and disposal.
However, enzyme stability and retention pose challenges which must be addressed
prior to scale-up, a task frequently accomplished by enzyme immobilization. The
authors report the first use of a recently reported leucine zipper system¹ to noncovalently immobilize an amine
dehydrogenase² (AmDH) and formate dehydrogenase
(FDH) onto methacrylate copolymer beads, which were subsequently employed in a
packed bed reactor with recycle. AmDHs convert
prochiral ketones into chiral amines with the addition of ammonia and oxidation
of NADH. FDH consumes formate to regenerate NADH from
NAD⁺, and generates carbon dioxide in the process. Key reactor
parameters, including residence time, reaction temperature, and recycle ratio, were
explored to determine their effects on space time yield and total turnover
number. Interesting flow patterns were observed and analyzed using high-speed
micro flow sensors. Finally, process control techniques allowed for steady flow
rates over long operation times, despite degradation of pump tubing. As the
biocatalytic production of pharmaceutical ingredients matures, more work must
be focused on bridging the gap between protein science and process development.
The reported work represents an important contribution to that effort.

1.            Caparco, A. A.; Bommarius, A. S.;
Champion, J. A., Effect of peptide linker length and composition on
immobilization and catalysis of leucine zipper-enzyme fusion proteins. AIChE Journal 2018, 64 (8), 2934-2946.

2.            Abrahamson,
M. J.; Vazquez-Figueroa, E.; Woodall, N. B.; Moore, J. C.; Bommarius, A. S.,
Development of an amine dehydrogenase for synthesis of chiral amines. Angew. Chem.-Int. Edit. 2012, 51 (16), 3969-72.