A porous vessel bioreactor for gel entrapped biocatalysts: Kinetic resolution of trans-methyl (4-methoxyphenyl)glycidate by Lecitase® Ultra in gelatin organogel (Gelozyme)

Preparation of trans-(2R,3S) methyl (4-methoxyphenyl)glycidate with enantiomeric excess (e.e.) of >99% has been carried out by enantioselective hydrolysis of the racemic glycidate ester by Lecitase® Ultra immobilized in macroporous gelatin organo-gel (gelozyme) in 47% yield. Effects of water content and particle size of the gel, different solvents, and flow rate of reaction medium on observed reaction velocity lead to optimum conditions. The reaction performed in a porous vessel bioreactor using toluene as preferred reaction medium, and gelatin-immobilized enzyme with average particle size of 1–1.2 mm, water content of 16.5% (w/w), and flow rate of 20 mL min−1, followed a typical Michaelis–Menten kinetics with apparent Vmax,app of 38 mM min−1 g−1 and apparent Km of 0.53 M. Theoretical considerations suggest that the bioreactor functions as a plug-flow reactor with complete recycle without serious pore diffusion and external mass transfer diffusion limitations. The immobilized enzyme can be used continuously for several recycles without significant loss of activity for at least two weeks.

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► Enantioselective reaction with e.e. > 99% without enzyme inhibition by product aldehyde.
► Porous vessel bioreactor avoids attrition and pressure drop problems in conventional reactors.
► Immobilized enzyme works for two weeks with stable activity.