Production of sulfur compounds by several yeasts of technological interest for cheese ripening

Several yeasts, Geotrichum candidum, Yarrowia lipolytica, Kluyveromyces lactis, Debaryomyces hansenii, and Saccharomyces cerevisiae, were studied for their ability to generate volatile sulfur compounds. These yeasts were cultivated on a synthetic culture medium supplemented with a biosynthetic precursor. With S-methylmethionine, dimethylsulfide (DMS) was the major sulfur compound produced. l-methionine promoted the synthesis of a wider spectrum of volatile sulfur compounds, methanethiol (MTL), DMS, dimethyldisulfide (DMDS), dimethyltrisulfide (DMTS) and S-methylthioacetate (MTA). Enzymatic activities possibly involved in sulfur compound synthesis were also investigated. Important l-methionine-transaminase activities, and also l-methionine-demethiolase activities were detected in cellular extracts. Their possible role in the generation of sulfur compounds and related biosynthetic pathways are also discussed.