Rhodotorula grandnis KGX-39 is an imperfect yeast and can grow on mandelate as sole source of carbon and energy. D(-)-Mandelate dehydrogenase and L(+)-mandelate dehydrogenase oxidise the respective enantiomers of mandelate to phenylglyoxylate which in turn is metabolized by peripheral and secondary metabolic pathways to succinate and acetyl-CoA and these enter into the central metabolic pathways. The objective of the work described in this thesis was to purify and characterise the L(+)-mandelate dehydrogenase and to compare it with other similar prokaryotic and eukaryotic enzymes.