(R,R)-Butane-2,3-diol dehydrogenase from Bacillus clausii DSM 8716 T : Cloning and expression of the bdhA-gene, and initial characterization of enzyme.

•We report that the bdhA gene encoding a putative (R,R)-butane-2,3-diol dehydrogenase (bdhA) from Bacillus clausii DSM 8716T encodes a protein that is only distantly related to previously studied enzymes (homology 33–43%) and exhibited some uncharted peculiarities.•Using recombinantly in Escherichia coli produced enzyme we demonstrate that the enzyme catalyzes the (R)-specific oxidation of (R,R)- and meso-butane-2,3-diol to (R)- and (S)-acetoin with specific activities of 12U/mg and 23U/mg, respectively.•Likewise, racemic acetoin was reduced with a specific activity of up to 115U/mg yielding a mixture of (R,R)- and meso-butane-2,3-diol, while the enzyme reduced butane-2,3-dione (Vmax 74U/mg) solely to (R,R)-butane-2,3-diol.•The enzyme accepted a selection of vicinal diketones, α-hydroxy ketones and vicinal diols as alternative substrates.•Although the physiological function of the enzyme in B. clausii remains elusive, the data presented herein clearly demonstrates that the encoded enzyme is a genuine (R,R)-butane-2,3-diol dehydrogenase with potential for applications in biocatalysis and sensor development.