Some microorganisms can accumulate high amount of lipids. These lipids can be used as interesting alternative to petroleum for the production of fuels and chemicals in form of biofuels, cosmetics, food additives, detergents, plastics, etc.
Yeasts have been identified as the most promising microorganisms for microbial oil production. These organisms are microscopic unicellular fungi that present the important ability to grow using organic residues as carbon source.
Among the different carbon sources derived from organic wastes, volatile fatty acids (VFAs) are compounds of 2 to 6 carbons (acetic, propionic, butyric acid, etc.) which can be generated through anaerobic fermentation. Remarkably, the use of VFAs instead of sugar-based carbon sources for yeast fermentation reduces the production costs while avoiding residues treatment before disposal.
The Biotechnological Processes Unit at IMDEA Energy has recently published a scientific article* that explored lipid production efficiency of five yeasts grown on VFAs at different concentrations (5, 10 and 15 g/L):
- Cutaneotrichosporon curvatum
- Lipomyces lipofer
- Rhodotorula toruloides
- Cyberlindnera saturnus
- Yarrowia lipolytica
Results obtained demonstrated the feasibility of utilizing VFAs as an innovative low-cost substrate for microbial oil production. All the strains screened in this study grew well in VFAs-rich digestate and were able to accumulate lipids. The highest lipid accumulation (more than 34 % dry weight) was observed in C. curvatum and C. saturnus.
This work was carried out in collaboration with researchers from the department “Genetics, Cell and Developmental Biology” of the University of Patras (Greece), all of them experts in microbial oil production from wastes using oleaginous yeasts.
(*) Llamas M.; Dourou M. González-Fernández C.; Aggelis, G.; Tomás-Pejó, E.; “Screening of oleaginous yeasts for lipid production using volatile fatty acids as substrate”. Biomass and bioenergy 138 (2020) 105553. DOI: 10.1016/j.biombioe.2020.105553
More information: Elia Tomás Pejó, Senior Assistant Researcher, Biotechnological Processes Unit. firstname.lastname@example.org
Fluoresence mycroscopy pictures of lipid droplets morphology in C. curvatus (a), L. lipofer (b), R. toruloides (c), W. saturnus (d) and Y. lipolytica (e).