Chirality of the γ-lactones produced by Sporidiobolus salmonicolor grown in two different media

Sporidiobolus salmonicolor is an aroma‐producing yeast which gives a peach‐like smell to the culture media. The enantiomeric ratios of the five γ‐lactones produced by this yeast cultivated in two different media were determined by multidimensional gas chromatography (MDGC) on a fused silica capillary column coupled to a modified β‐cyclodextrin column. These ratios remain constant during growth and are not affected by the composition of the medium. The (R)‐enantiomer is highly predominant (99%) for γ‐decalactone and predominant (68–88%) for γ‐octalactone, γ‐nonalactone, and (Z6)‐γ‐dodecenolactone. A ratio close to racemic was found for γ‐dodecalactone. A discussion on the metabolic origin of these lactones is based on the analysis of the enantiomeric ratios obtained. With respect to consumers' preference for products considered as “natural,” microbial lactone production may represent a valuable alternative to fruit flavors. The enantiomeric lactone ratios produced by Sporidiobolus salmonicolor are compared with those reported from some fruits. Chirality 9:667–671, 1997. © 1997 Wiley‐Liss, Inc.