Microbial oil production by Yarrowia lipolytica strains using glycerol as carbon source

Abstract

Yeasts can produce microbial oil from hydrophobic substrates such as glycerol, a byproduct of the biodiesel industry that is often undervalued in the market. Yarrowia lipolytica is capable of degrading glycerol and is considered a model organism for studying lipid accumulation. Different yeast strains and culture conditions can result in varying lipid yields with distinct fatty acid profiles. Thus, in this study, five strains of Y. lipolytica were tested for microbial oil production using pure glycerol at temperatures of 15 °C and 25 °C. None of the isolates were considered oleaginous at 15 °C. However, at 25 °C, the isolates UFMG-CM-Y6114 (from cheese), UFMG-CM-Y4187 (from beach sand), and UFMG-CM-Y6189 (from Antarctica) produced more than 20% lipid content (29.30%, 26.95%, and 34.38%, respectively). No significant differences in lipid content were observed between the UFMG-CM-Y6114 and UFMG-CM-Y4187 strains. The cheese- and Antarctica-derived strains were further tested for their ability to accumulate oil when grown on crude glycerol. Among them, UFMG-CM-Y6189 showed the best performance, producing 9.40 g·L⁻¹ of biomass, 1.90 g·L⁻¹ of lipid yield, and 21.56% lipid content, while consuming 61.3 g·L⁻¹ of glycerol. The fatty acid profile of these lipids was predominantly monounsaturated (59.5%), with oleic acid (49.4%) as the main component. This, combined with a low polyunsaturated fatty acid content (5.2%), makes these lipids particularly suitable for biodiesel production. Therefore, the lipids from the Y. lipolytica strain UFMG-CM-Y6189 represent a promising raw material for biodiesel production from glycerol.