cell growth will be reduced in the high volume loading flasks.
The medium composition and agitation speed were the same for
different flasks; 90 g/L of glucose was used as a carbon source.
It was found that within the range of liquid loading from 25 to
100 mL per flask, the cell growth remained at a relatively stable
level (Table 12); the differences between different liquid
loadings were insignificant (P > 0.1). The results indicate that
for the experimental conditions used in this work, the oxygen
supply is not a limiting factor. In addition to the flask culture, a
bioreactor (New Brunswick, BioFlow 110) culture of this alga
is being conducted in an ongoing project. The preliminary data
shows that when the dissolved oxygen was set at 50% of
saturated level, the cell density obtained in the batch culture of
the bioreactor was similar to that obtained from the flask
cultures. This further confirmed that the oxygen was not
influencing the results. The similar algal growth in glucose- and
glycerol-medium was considered due to the specific characteristics
of the algal species used in this study. Indeed,
S. Limacinum has been reported a good DHA producer when
growing in glucose or glycerol, the two carbon sources provides
a similar algal growth and DHA production [16].