Sweet and sour potential of yeast from the Yarrowia clade
Résumé
The food industry is witnessing a growing demand for food additives. Microbial fermentation is an attractive way to produce them using microorganisms, including the yeast Yarrowia lipolytica. Twelve species of the Yarrowia clade were screened for erythritol, mannitol and citric acid production from pure glycerol, glucose or fructose in four different media. During shake-flask cultures, only Y. lipolytica was able to secrete citric acid. Glycerol was found to be the best substrate for erythritol and mannitol biosynthesis by all the species. The six best candidate species for sweetener biosynthesis were cultivated in bioreactors. Up to 69.8 g dm−3 of total polyols with a yield of 0.59 g g−1 was obtained for Candida oslonensis, the best sweetener producer. It secreted 44.6 g dm−3 of erythritol (QEry = 1.16 g dm−3 h−1 and YEry/S = 0.4 g g−1) and 34 g dm−3 of mannitol (0.29 g g−1). Additionally, Candida hollandica and Yarrowia divulgata represent promising species for which media composition and culture parameters still have to be optimized.