Haloquadratum walsbyi Yields a Versatile, NAD+/NADP+ Dual Affinity, Thermostable, Alcohol Dehydrogenase (HwADH)

Abstract

This study presents the first example of an alcohol dehydrogenase (ADH) from the halophilic archaeum Haloquadratum walsbyi (HwADH). A hexahistidine-tagged recombinant HwADH was heterologously overexpressed in Haloferax volcanii. HwADH was purified in one step and was found to be thermophilic with optimal activity at 65 °C. HwADH was active in the presence of 10% (v/v) organic solvent. The enzyme displayed dual cofactor specificity and a broad substrate scope, and maximum activity was detected with benzyl alcohol and 2-phenyl-1-propanol. HwADH accepted aromatic ketones, acetophenone and phenylacetone as substrates. The enzyme also accepted cyclohexanol and aromatic secondary alcohols, 1-phenylethanol and 4-phenyl-2-butanol. H. walsbyi may offer an excellent alternative to other archaeal sources to expand the toolbox of halophilic biocatalysts.

Exploring Oxidoreductases from Extremophiles for Biosynthesis in a Non-Aqueous System

“…The benefits from a high throughput platform for cloning genes, protein expression, and characterization of selected candidates have been explored. Jennifer et al [ 9 ] reported halophilic alcohol dehydrogenase from the Haloquadratum walsbyi (HwADH), which was active in the presence of 10% ( v / v ) organic solvents (acetone, ACN, MeOH and iPrOH). The enzyme displayed NAD + /NADP + dual cofactor specificity and a broad substrate scope, including benzyl alcohol and 2-phenyl-1-propanol, acetophenone, and phenylacetone.…”