Physiology of stress response in Spirulina spp.

The physiological and biochemical response to temperature, light and salinity stress was investigated in some Spirulina spp. strains from different habitats. In S. maxima Sosa6 the study was extended to the specific structural modifications related to light stress. In this strain drastic changes in the intracellular organization of the thylakoid membranes were observed, during up-shift in light intensity. The response to the examined stress was consistent for all the strains tested, although the extent of changes varied. In particular high growth temperatures or high salinity led to an increased degree of saturation in the fatty acid content, as observed in detail in Spirulina platensis strain M2. The results showed that strains, despite substantial similarities in the stress response, exibited inherent differences, which seem to depend on their specific physiological and biochemical characteristics. This behaviour could be helpful in the selection of suitable strains for successful exploitation of Spirulina as a source of valued products.