Oleaginous Yeasts Growing On Microbrewery Spent Liquids

ANDREA TROCHINE; RODRIGO ACOSTA; MARTÍN MOLINÉ; ANTONIO UTTARO; DIEGO LIBKIND

SC de Bariloche

Congreso; 34º International Specialized Symposium On Yeasts; 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 yeasts producing these valuable lipids is one of the challenges for feasible industrial productions. In this work, lipid production of five oleaginous yeast strains from Patagonia and Antarctica, was evaluated using microbrewery effluents as sole nutrient source. Yeasts were grown on YPD and then transferred to brewery spent liquid (5 brix boil remainings) and grown seven days at 20°C, 180 rpm. Subsequently, cells were used for 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 pullulans M425b, 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 this yeast 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 150 to 300 μg/g. As for COD removal, H. festucosa removed 73% of initial COD, followed by S. ruberrimus (63%). In consistency, both strains left few remaining sugars. R. taiwanensis removed only 29% COD and was unable to use dextrins and maltotriose and only used less than half available maltose. Total Nitrogen was removed between 52 to 71% (G. pullulans) and total P 43 to 82% (S. ruberrimus). As a conclusion S. ruberrimus CRUB1640 shows potential for its use in lipid production using brewery effluents. Future analyses will include mixed strain cultures and different brewery spent liquids.