Effect of macro- and micro-nutrient limitation on superoxide dismutase activities and carotenoid levels in microalga Dunaliella salina CCAP 19/18

The aim of this study was to assess the effects of sixteen stress conditions on total carotenoid production and the response of antioxidative enzyme superoxide dismutase (SOD) in microalga Dunaliella salina. Of the stress conditions tested, high-light illumination (240 μmol photons m−2 s−1) in combination with nitrogen depletion were the conditions associated with maximum carotenoid production and which induced Fe-SOD and retained the specific Mn-SOD isoform. Removal of the micronutrients manganese (Mn), Zinc (Zn) and Iron (Fe) as well as nitrogen from the medium enhanced carotenoid production on day 5, while the removal of nitrogen and Mn from the growth medium drastically affected carotenoid production at all time-points. The differential response of SODs influences the levels of carotenoid biosynthesis as chronic molecular defence strategies of D. salina.