LIPID PRODUCTION OF YEASTS GROWING ON THREE DIFFERENT MICROBREWERY SPENT LIQUIDS

ANSALDI N; TROCHINE A

San Carlos de Bariloche

Workshop; International Workshop on Brewing Yeasts (IWOBY); 2021

IPATEC - Fundación CRELTEC

Yeasts accumulating more than 20% of their dry weight in lipids are considered oleaginous.These lipids are mainly triacylglycerides and may serve in biodiesel production, animal andhuman nutrition, among others. Finding low cost carbon sources to grow yeasts accumulating these valuable lipids is one of the challenges for feasible industrial productions. Microbrewery spent liquids (MSL), one of the main by-product of brewing industry, have high organic contents and need treatment to reduce them before being released into the environment. In this work, lipid production ability of seven oleaginous yeast strains isolated from Patagonia and Antarctica was evaluated using three different MSLs as sole nutrient source. The MSLs used were 5° Bx boiling remaining from three different beer styles (Kölsch, Stout and IPA) and were characterized in the sugar composition, chemical oxygen demand (COD) and free amino nitrogen (FAN). All strainswere grown in MSLs for 168 h and incubated at 20°C in an orbital shaker (180 rpm); yeastsgrowth, lipid qualitative and quantitative characteristics were evaluated (gravimetric and GC-FID lipid analyses). All yeast strains (Dioszegia patagonica ANT99, Rhodotorula taiwanensis CRUB1425, Sporobolomyces ruberrimus CRUB1640, Tausonia pullulans M425b, Holtermanniella festucosa CRUB1358, Solicoccozyma aeria A3-2.12 and Holtermanniella wattica B2-5.3) showed high biomass production (between 6 and 17 g/L) with S. aeria A3-2.12 and H. wattica B2-5.3 showing the highest values in all the MSLs. S. ruberrimus CRUB1640 (5.5-8.1 g/L) and S. aeria A3-2.12 presented the highest lipid production (5.5-8.1 g/L and 6.8-8.6 g/L respectively); both also showed the highest lipid production on cell dry weight (47-56% and 42-53% respectively). Fatty acid profiles of all strains were dominated by oleic (37-65%), linoleic (9-24%), palmitic (15-28%) and stearic (2-10%) acids. Based on these results, S. aeria A3-2.12 and S. ruberrimus CRUB1640 were selected for future lipid production and COD removal optimization assays.