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Advisor(s)
Abstract(s)
This study aims at evaluating the influence of mixotrophic growth and salinity stress in the lipid content and
productivities of microalgae Arthrospira platensis (A. platensis) and Chlorella vulgaris (C. vulgaris). For
comparison purposes, both microalgae were also cultivated in the standard autotrophic conditions: modified
Zarrouk’s medium for A. platensis and Bold’s basal medium for C. vulgaris. The mixotrophic conditions were
created by adding 1.00 g/L of glucose to their standard media, and the salt stress was induced by introducing
sodium chloride (NaCl) in different amounts. As expected, the biomass concentration and productivity
increases under mixotrophy but decreases with salinity stress. Therefore, although the lipid content increased
with the salinity stress under mixotrophy, reaching maximum values of 15.4 and 23.0 % dry weight (dwt)
respectively, for A. platensis (in 0.428 M of NaCl) and C. vulgaris (in 0.0214 M of NaCl), the biomass
productivity reached minimum values. Consequently, the maximum biomass and lipid productivities were
obtained with an intermedium lipid content and without the salinity stress. The maximum biomass and lipid
productivities are 99.7 and 9.7 mg/L/day for A. platensis and 227.2, and 37.7 mg/L/day for C. vulgaris,
respectively. This study also revealed that C. vulgaris adapts faster to salinity stress, whereas A. platensis is
able to tolerate higher salinity concentrations.