Helmholtz-Gemeinschaft

Conclusion & Outlook
the surrounding solution. This would also further explain the discussed inactivation
mechanism.
Due to the heterogeneity of the observed effects with different aldehydes a general
stabilization of BAL can most probably not be achieved by only few amino acid exchanges. It
can be assumed that multiple mutations would be necessary to achieve sufficient stabilization
towards various aldehydes. However, multiple mutations bear the risk of structural
destabilization and inactivation, which makes such an approach less favourable. BAL shows a
very high catalytic activity in the beginning of reactions, which rapidly decreases by aldehyde
induced inactivation. Therefore it seems to be the best choice to add fresh enzyme at distinct
time points, when used in emulsion systems with high substrate concentrations and long
reaction times. In homogeneous reaction systems with cosolvents the solubility of the
aromatic compounds limits the substrate concentration applied. In such systems addition of a
high enzyme concentration can be useful in order to reach full conversion before BAL is
finally inactivated.
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