Selection of oleaginous yeasts able to accumulate lipids from culture media containing glycerol as the sole carbon source

The biodiesel is currently produced mainly from edible oils as feedstock, generating glycerol as a by-product. The use of glycerol as a carbon source for oil production by oleaginous yeasts contributes to the development of alternative routes of oil production in the context of the circular economy. Therefore, this study aimed to select oleaginous yeasts capable of producing oil in culture media containing glycerol as a carbon source. A total of 10 yeasts capable of assimilating glycerol as carbon source were evaluated for their ability to produce lipids in a glycerol culture medium to select a promising oleaginous yeast. Herein, the isolate CA8 was selected as the best lipid producer from glycerol considering the achieved values of lipid content (%), lipid titer (g/L), and biomass (g/L). This isolate was taxonomically identified as Meyerozyma guilliermondii and designated as Meyerozyma guilliermondii UFV-2. Since the C: N ratio notably influences lipid production by oleaginous yeasts, the effect of different C:N ratios on biomass production, lipid content and lipid titer were evaluated. The highest values of biomass formation, lipid content, and lipid titer, recorded in a C: N of 150:1, were 6.77 g/L, 25 % (w/w), and 1.71 g/L, respectively recorded. The lowest biomass formation 4.67 g/L was recorded in a C: N ratio of 75:1. Taken together, these results indicate that M. guilliermondii UFV-2 displays the potential to produce lipids from glycerol, opening perspectives for further studies that aim to optimize the production parameters. Keywords: Biodiesel; Meyerozyma guilliermondii; Yeast oil; Circular economy; Carbon- nitrogen ratios.