Immobilisation of alcohol dehydrogenase from Lactobacillus brevis and its application in a plug-flow reactor

The immobilisation of alcohol dehydrogenase from Lactobacillus brevis (E.C. 1.1.1.2) on an amino-epoxy support (amino-epoxy Sepabeads®) has been investigated with regards to increasing stability under storage and process conditions. After the standard immobilisation procedure resulted in no significant stabilisation, we found a fourfold increase in stability by blocking the remaining functional groups on the enzyme-support preparations with glycine or mercaptoethanol. However, stabilising the multi-point covalent attachment could only be achieved by additionally cross-linking the adsorbed proteins with glutardialdehyde. By this means, we achieved a high stabilisation effect, resulting in a half-life time of over 1200 h when stored at 30 °C. This means a 60-fold increase in stability compared to the soluble enzyme.To determine the operational stability, the enzyme-support preparation was applied to the production of (R)-phenylethanol from acetophenone in a plug-flow reactor, which could be operated for over 10 weeks with an excellent enzyme utilisation.

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