Fig. 1(a–c)
shows the time course of biomass, substrate consumption
and pH condition of the microalgal cultures
with 30 g glucose/l, pure glycerol and real glycerol
(SE crude glycerol) being used as substrates in the
medium. As shown in Fig. 1(b, c), the cells grew well
in pure and crude glycerol and the biomass reached
peak levels in 5–6 days. Crude glycerol consumption
was low during first two days (0.85–0.46 g substrate
consumed/g cells), but after that the cells became
acclimated and then the substrate uptake increased to
0.91–1.18 g substrate consumed/g cells during days
three through six. Glucose was completely consumed
in four days which resulted in termination of growth
due to lack of substrate (Fig. 1 a).