An isolated enone reductase characterized by a molecular mass of 61300+/−5000 Da; NADPH and NADPH as co-factor; a temperature optimum of 55–60° C. at pH 7.4; a pH optimum of 4.5–8.5 and substrate specificity on ∝,β-unsatured ketones; a process for producing it from a microorganism and a process for producing levodione from ketoisophorone using such reductase.