Physiological performance of blue-green algae from fields of Nile Delta region in Egypt

The broad diversity of blue-green algae (cyanobacteria) allows the production of a wide range of useful bioactive compounds used as nutraceuticals, pharmaceuticals, cosmetics, food additives, and different types of biofuels. In spite of many efforts to study the morpho-taxonomy of the available cyanobacterial biodiversity in the Middle East region, very little studies were made to assess the physiological performance of these existing taxa, especially in Egypt. This study, thus, aims to evaluate the ecophysiological adaptation of eight cyanobacterial isolates, from the Nile Delta region of Egypt, in terms of biomass productivity and their adaptability to different environmental conditions. Results revealed that the best biomass productivity was recorded in Anabaena fertilissima isolate at both 21 and 28 days culture age when grown in nitrogen free BG11 medium. Regarding specific growth rate, the highest values in A. fertilissima and A. sphaerica recording 0.102 and 0.088 d(-1), respectively. Similarly, chlorophyll-a concentration was highest in A. fertilissima. Moreover, all isolates showed differential response to several media supplementation including NaCl, nitrogen and FeCl3. Furthermore, Mixotrophic growth using glucose was highly toxic to growth of isolates on agarized BG11 media. However, growth was boosted when sucrose, glycerol, and mannitol were used as external organic carbon sources. Future studies involving superior isolates like A. fertilissima and A. sphaerica are recommended to screen for useful bio products.