Lipid production in the under-characterized oleaginous yeasts, Rhodosporidium babjevae and Rhodosporidium diobovatum, from biodiesel-derived waste glycerol

The growth, lipid production, and carbon use efficiency of two oleaginous yeasts, Rhodosporidium babjevae and Rhodosporidium diobovatum, were compared under nitrogen-limiting conditions with glycerol as the carbon source. Final biomass concentrations of R. babjevae and R. diobovatum were 9.4 +/- 0.80 g/L and 12.0 +/- 0.82 g/L, respectively, after 120 h of growth. Final lipid accumulation in for R. babjevae and R. diobovatum were 34.9 +/- 3.0% cell dry weight (cdw) and 63.7 +/- 4.5% cdw, respectively. Biomass production increased to 9.9 +/- 0.2 g/L for R. babjevae and 14.1 +/- 0.2 g/L for R. diobovatum in medium containing biodiesel-derived waste glycerol, but lipid accumulation decreased in both species. In a 7 L bioreactor with biodiesel-derived glycerol as carbon source, R. diobovatum produced 13.6 +/- 0.4 g/L biomass and accumulated lipids to 50.7 +/- 2.2% cdw, matching flask experiments. (C) 2015 Elsevier Ltd. All rights reserved.