The lipid concentration and
productivity of crude glycerol culture reached 14.6
and 2.4 g/l day, respectively. Figure 2 shows comparison
of biomass and lipid productivity in batch
fermentations by C. protothecoides with different
carbon substrates after four days of cultivation. No
significant difference of biomass concentration and
lipid productivity obtained for glucose culture and
pure glycerol culture was observed (a = 0.05), but
those obtained from the crude glycerol culture were
significantly greater. This result indicated that growth
of C. protothecoides on pure glycerol had similar
effects on biomass and lipid productivity as those
from glucose in the batch fermentation. Another
study also found that growth of Chlorella vulgaris on
pure glycerol had similar dose effects as those grown
on glucose (Liang et al. 2009).