Authors: AnnKathrin Liliensiek Jennifer Cassidy Gabriele Gucciardo Cliadhna Whitely Francesca Paradisi
Publish Date: 2013/05/05
Volume: 55, Issue: 2, Pages: 143-149
Abstract
Replacement of chemical steps with biocatalytic ones is becoming increasingly more interesting due to the remarkable catalytic properties of enzymes such as their wide range of substrate specificities and variety of chemo stereo and regioselective reactions This study presents characterisation of an alcohol dehydrogenase ADH from the halophilic archaeum Halobacterium sp NRC1 HsADH2 A hexahistidinetagged recombinant version of HsADH2 HisHsADH2 was heterologously overexpressed in Haloferax volcanii The enzyme was purified in one step by immobilised Niaffinity chromatography HisHsADH2 was halophilic and mildly thermophilic with optimal activity for ethanol oxidation at 4 M KCl around 60 °C and pH 100 The enzyme was extremely stable retaining 80 activity after 30 days HisHsADH2 showed preference for NADPH but interestingly retained 60 activity towards NADH The enzyme displayed broad substrate specificity with maximum activity obtained for 1propanol The enzyme also accepted secondary alcohols such as 2butanol and even 1phenylethanol In the reductive reaction working conditions for HisHsADH2 were optimised for acetaldehyde and found to be 4 M KCl and pH 60 HisHsADH2 displayed intrinsic organic solvent tolerance which is highly relevant for biotechnological applicationsFP acknowledges funding under the Science Foundation Ireland Research Framework Programme and the EPA Kind donations of the strain H sp NRC1 by Prof P Engel and the expression system H volcanii H1209H1325/pTA963 by Dr T Allers are gratefully acknowledged
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