Yeasts are microscopic and unicellular fungi employed in everyday life. These microorganisms arise as promising industrial alternatives to replace petroleum in the production of chemicals and fuels. In fact, yeasts can produce biofuels such as bioethanol and accumulate lipids that can be further converted into biodiesel, cosmetics, food additives, detergents and plastics.
However, due to their high production cost, considerable efforts have been addressed to find new alternative carbon sources for yeasts growth. In this context, volatile fatty acids are compounds from 2 to 6 carbons (acetic, propionic, butyric acid, etc.) that can be considered low-cost substrates for yeasts cultivation since they can be generated from a wide variety of organic wastes through anaerobic fermentation. This fermentation is a bioprocess where some hydrolytic and acidogenic bacteria degrade the organic matter contained within the wastes giving rise to a volatile fatty acids rich effluent.
Thus, in a first step, volatile fatty acids are produced from organic wastes, and in a second step, these acids are utilized as carbon source for the yeast to produce bioproducts. The integration of these two bioprocesses allows the valorisation of residues while reducing of the carbon source cost.
The Biotechnological Processes Unit at IMDEA Energy has recently published a scientific article* where the capacity of the oleaginous yeast Yarrowia lipolytica to consume volatile fatty acids was assessed taking into account the toxic effect of these acids on yeast growth. Remarkably, the yeast was able to grow on high concentration of volatile fatty acids demonstrating the feasibility of utilizing anaerobic fermentation effluents as an innovative low-cost substrate for yeasts.
(*) Llamas, M., Tomás-Pejó, E., González-Fernández, C. VOLATILE FATTY ACIDS FROM ORGANIC WASTES AS NOVEL LOW-COST CARBON SOURCE FOR Yarrowia lipolytica (2020) New Biotechnology, 56, pp. 123-129. https://doi.org/10.1016/j.nbt.2020.01.002
More information: Mercedes Llamas, Predoctoral researcher, Biotechnological Processes Unit firstname.lastname@example.org