Study of Metabolic Adaptation of Red Yeasts to Waste Animal Fat Substrate

Carotenogenic yeasts are non-conventional oleaginous microorganisms capable to utilize various waste substrates. In this work 4 red yeast strains (Rhodotorula, Cystofilobasidium and Sporobolomyces sp.) were cultivated in media containing crude, emulsified and enzymatically hydrolysed animal waste fat, compared with glucose and glycerol as single C-sources. Cell morphology (cryo-SEM, TEM), production of biomass, lipase, biosurfactants, lipids (GC/FID) carotenoids, ubiquinone, ergosterol (HPLC/PDA) in yeast cells was studied depending on medium composition, C-source and C/N ratio. All studied strains are able to utilize solid and processed fat. Biomass production at C/N=13 was higher on emulsified/hydrolysed fat than on glucose/glycerol. Production of lipids and lipidic metabolites was enhanced for several times on fat; the highest yields of carotenoids (24.8 mg/l) and lipids (54.5%/CDW) were found in S.pararoseus. Simultaneous induction of lipase and biosurfactants was observed on crude fat substrate. Increased C/N ratio (13-100) led to higher biomass production in fat media. Production of total lipids increased in all strains to C/N 50. Oppositely, production of carotenoids, ubiquinone and ergosterol dramatically decreased with increased C/N in all strains. Compounds accumulated in stressed red yeasts are having great application potential and can result from valorization of animal waste fat in the biorefinery concept.Karotenogenní kvasinky jsou schopny utilizovat řadu různých substrátů včetně odpadů. V této práci je popsána kultivace vybraných kmenů karotenogenních kvasinek rodů Rhodotorula, Cystofilobasidium, and Sporobolomyces sp. v médiu obsahujícícm surový odpadní živočišný tuk a upravený substrát emulsifikací a enzymovou hydrolýzou. Výsledky byly srovnány s kultivací na glukóze a glycerolu jako jednoduchých zdrojích uhlíku