Process for preparing saturated lactones, products produced therefrom and organoleptic uses of said products

A process for the production of a δ-lactone compound represented by the structural formula:

• wherein R is a member selected from the group consisting of methyl and n-propyl comprising:
• (a) preparing an aqueous nutrient medium containing a nutrient source, a buffer and yeast extract at a pH in the range of from about 3.5 up to about 8.0;
• (b) preparing as a Saccharomyces yeast culture suspension by inoculating a medium comprising water, a carbon source, a nitrogen source and one or more inorganic salts with a Saccharomyces yeast;
• (c) mixing the resulting yeast culture suspension with the aqueous nutrient medium in order to form a first aqueous liquid phase
• (d) preparing as a second organic liquid phase an admixture of:
• (i) an organic phase former which is a triglyceride of a fatty acid or high molecular weight hydrocarbon;
• and
• (ii) a natural 2-decen-1,5-olide or a natural 2-dodecen-l,5-olide represented by the structural formula:
• wherein R is selected from the group consisting of methyl and n-propyl;
• (e) mixing said first aqueous liquid phase and said second organic liquid phase together with agitation in order to form a reaction medium;
• (f) feeding dextrose to said reaction medium at a rate of 5 to 72 g/L/hr so as to maintain said dextrose at a concentration of from 0.01 up to 1.5 grams/liter;
• and
• (g) supplying the reaction medium with an oxygen-containing gas at such a rate as to enable the oxygen level in the reaction medium to be maintained at a level of at least about 0.1 liters/liter of reaction mixture;
• whereby at least 10% dissolved oxygen as measured by a standard oxygen probe is present in the reaction medium at all times during the reaction, in order to maintain oxidative growth conditions to thereby achieve a biotransformation in the presence of a yeast capable of producing said natural δ-lactone compound having the structure:
• the biotransformation being carried out at a temperature in the range of from 20-50° C.