also reported that Nannochloropsis sp. could be cultivated with a
strong intensity of light.
Although increasing the light intensity enhanced the growth of
both strains, it reduced their lipid content. A low light intensity
was more suitable for lipid accumulation than a high light intensity.
Since the high light intensities enhanced the growth of microalgae,
the microalgae might use synthesized energy to divide
themselves rather accumulate it in lipid form. Although, there
was no obvious photoinhibition effect on the growth of Nannochloropsis
sp., its lipid content was more susceptible to photoinhibition
than did marine Chlorella sp. From these results, it could be
concluded that the optimal levels of light intensity for supporting
cell growth and lipid accumulation were different. To obtain a high
cell dry weight, the light intensity should be increased but a low
intensity of light was more favorable for the lipid accumulation.
This result is in contrast to that of the previous reports which
had shown that a high light irradiance was favored for more lipid
and hydrocarbon contents rather than more biomass (Metzger
and Largeau, 1999; Tansakul et al., 2005).