INFLUENCE OF TEMPERATURE ON GROWTH AND BIOCHEMICAL COMPOSITION OF SPIRULINA PLATENSIS AND S. FUSIFORMIS

Abstract

The influence of temperature on growth and biochemical constituents of two species of Spirulina; Spirulina platensis and Spirulina fusiformis was studied. Various temperatures as 20, 25, 30, 32, 35, 37 and 40 0 C were investigated. Maximum specific growth rate of 0.141 was found at 32 0 C for S. platensis and that of 0.144 was found at 37 0 C for S. fusiformis. Both species showed negligible growth at 20 0 C and 40 0 C and after 6−8 days culture collapsed. Maximum protein content was found at 32 0 C for S. platensis and at 30 0 C for S. fusiformis and was 59.0 and 62.3 %, respectively. At 37 0 C a significant increase in carbohydrates and in lipids were observed for both species; S. platensis (29.3 and 10.5%) and S. fusiformis (24.3 and 11.0%). Maximum biomass production of 2.4 g l -1 and chlorophyll a production of 16.6 mg l -1 were observed at 32 0 C for S. platensis. Maximum biomass production of 2.3 g l -1 and chlorophyll a production of 14.2 mg l -1 were observed at 37 0 C for S. fusiformis. A net increase in phycocyanin occurred in both species when cultures were grown at the suboptimal temperature of 25 0 C. From the results the optimal growth temperature for S. platensis found at 32 0 C and that for S. fusiformis found at 37 0 C. It can be concluded from the findings that both species are suitable for culture in the tropics.