OLEAGINOUS YEASTS GROWING ON MICROBREWERY SPENT LIQUIDS

TROCHINE A; UTTARO AD; ACOSTA R; LIBKIND D; MOLINÉ, M

San Carlos de Bariloche

Simposio; International Specialized Symposium on Yeasts 34 (ISSY34); 2018

IPATEC

Yeasts accumulating more than 20% of their dry weight in lipids are consideredoleaginous. These lipids are mainly triacylglycerides and may serve in biodieselproduction, animal and human nutrition, among others. Accumulation occurs undernutrient deprivation (e.g. N) and excess C. Finding low cost C sources to grow yeastsproducing these valuable lipids is one of the challenges for feasible industrialproductions. In this work, lipid production of five oleaginous yeast strains fromPatagonia and Antarctica, was evaluated using microbrewery effluents as sole nutrientsource. Yeasts were grown on YPD and then transferred to brewery spent liquid (5 brixboil remainings) and grown seven days at 20°C, 180 rpm. Subsequently, cells were usedfor biomass, lipid and carotenoid analyses. Supernatants were used for ChemicalOxygen Demand (COD), N, and P analyses. Also, remaining sugars were evaluated byHPLC (dextrins, maltotriose, maltose, glucose). All yeast strains (Guehomyces pullulansM425b, Holtermaniella festucosa CRUB1358, Dioszegia patagonica ANT99,Sporobolomyces ruberrimus CRUB1640 and Rhodotorula taiwanensis CRUB1425)produced 10 to 12 g/L of biomass, excepting R. taiwanensis (5.7 g/L). Nevertheless thisyeast together with D. patagonica and S. ruberrimus were the best lipid producers (3.5,4 and 6.3 g/L respectively). These three strains also produced carotenoids, ranging 150to 300 μg/g. As for COD removal, H. festucosa removed 73% of initial COD, followed byS. ruberrimus (63%). In consistency, both strains left few remaining sugars. R.taiwanensis removed only 29% COD and was unable to use dextrins and maltotriose andonly used less than half available maltose. Total Nitrogen was removed between 52 to71% (G. pullulans) and total P 43 to 82% (S. ruberrimus). As a conclusion S. ruberrimusCRUB1640 shows potential for its use in lipid production using brewery effluents.Future analyses will include mixed strain cultures and different brewery spent liquids.