The yeast Yarrowia lipolytica growing on methyl ricinoleate produces various lactones, ␥-decalactone, the worthy aroma compound, 3-hydroxy-␥-decalactone without sensorial properties and two decenolides of various interest. Unfortunately, these three latter lactones are produced at high levels by this yeast, decreasing yields and complicating the extraction of ␥-decalactone. In this study, the production of ␥-decalactone was increased through a genetic engineering of the strain and the accumulation of the three other lactones was lowered. Theses results show that it is possible to improve the mastering of the complex ␤-oxidation pathway (the metabolic pathway involved in these bioconversions) by playing on genetic factors.