Method for producing lactones from a strain of Aureobasidium pullulans

The invention relates to a method for producing lactones from a strain of Aureobasidium pullulans that are produced from a pre-culture of the Aureobasidium pullulans strain CBS 771.97, obtained from CBS-KNAW Fungal Biodiversity Center, Uppsalalaan 8, 3584 CT Utrecht, Netherlands, or related strains; from an inoculum obtained from the pre-culture; a culture is produced by fermentation at a temperature between 20° C. and 40° C. over a period of at least 3 days so as to produce metabolites, in a sterilized aqueous production medium containing: a carbon source; a nitrogen source; a mineral salt solution; and a calcium source, at a concentration between 2 and 100 mM; and following the fermentation period, converting the metabolites produced into a lactone mixture comprising (R)-5,6-dihydro-6-pentyl-2H-pyran-2-one (or (R)-(−)-massoia lactone) and/or (4R,6R)-4-hydroxy-6-pentyl-tetrahydro-2H-pyran-2-one.