Fig. 1

Growth profiles of R. toruloides, C. curvatus and L. starkeyi shake flasks cultivated with different concentrations of pure and crude glycerol. Growth curves (OD660 nm) of R. toruloides (a), C. curvatus (b) and L. starkeyi (c) cells at 25 °C and 220 rpm. Glycerol was used as sole carbon source at the final concentration of 100 g L⁻¹. Five different mix of pure and crude glycerol were evaluated: 100 % pure glycerol (A dashed line and unfilled square), 80 % pure and 20 % crude glycerol (B continuous line and filled circle), 70 % pure and 30 % crude glycerol (C continuous line and filled triangle), 50 % pure and 50 % crude glycerol (D continuous line and filled diamond) and 100 % crude glycerol (E continuous line and filled square). Data are mean ± standard deviation (error bars) of three independent assays