Abstract

Three yeast strains were isolated from decaying wood in the Chilean Valdivian forest and their ability to grow in model lignocellulosic media and agroindustrial bioproducts was studied. The yeasts, identified as Scheffersomyces coipomensis, Sugiyamaella paludigena and Meyerozyma guilliermondii (GenBank code: KX609756, KX609757 and KX609758, respectively), were cultivated in media containing glucose, xylose or mannose (at 40 g/L) or a mixture of them (at 40 g/L each, in total 120 g/L) and on liquid extract from industrial pomegranate residual. The yeast biomass, lipid and ethanol production were evaluated at 28 ºC during 160 h under aerobic and anaerobic conditions. The experimental data showed significant differences in biomass production (X, g/L), ranging from 0.7 g/L to 14 g/L. In model lignocellulosic media lipids were accumulated in various percentages from 6.9% w/w to 24.7% (w/w), the higher production being observed in S. coipomensis cultures using mannose as carbon source (I.e. lipid yield 0.09 g/g). The fatty acid composition was similar in lipids produced by the three strains, having oleic acid as the most abundant fatty acid in all experimental conditions. M. guilliermondii and S. paludigena, but not S. coipomensis, were able to grow on pomegranate residues based substrate, producing significant ethanol quantities under both aerobic and anaerobic conditions. We conclude that the above newly isolated strains, especially S. coipomensis and M. guilliermondii could be employed in the future for converting lignocellulosic biomass and industrial pomegranate residues to lipid and ethanol suitable as biofuels.