A levodione reductase having the following physical properties is provided: molecular weight: from about 142,000 to about 155,000±10,000 (consisting of four homologous subunits having a molecular weight of 36,000±5,000); co-factor: nicotinamide adenine dinucleotide (AND/NADH); substrate specificity: active on levodione; optimum temperature: about 15° C. to about 20° C. at pH 7.0; optimum pH: 7.5; and activator: K+, Cs+, Rb+, Na+ and NH4+. The levodione reductase according to the present invention produces actinol, an important intermediate for the production of zeaxanthin, from levodione. This enzyme may be produced from a microorganism belonging to the genus Corynebacterium, preferably the microorganism Corynebacterium aquaticum AKU 611 (FERM BP-6448) or a functional equivalent, subculture, mutant or variant thereof. Also provided is a process for producing the levodione reductase that includes cultivating a microorganism of the genus Corynebacterium in an aqueous medium under aerobic conditions, disrupting the cells of the microorganism and isolating and purifying the levodione reductase from the cell-free extract. A process for producing actinol from levodione is also provided that includes contacting levodione with levodione reductase in the presence of the reduced form of nicotinamide adenine dinucleotide or a cell-free extract of the microorganism, and then isolating the resulting actinol from the reaction mixture.