Isolation, Identification and Growth Optimisation of Freshwater Microalgae

Özet

Microalgae have been widely used in aquaculture as feedstuff and feed additive. The aim of this research was to isolateand identify the microalgae derived from a pool used to breed soft-shell turtles. Therefore, the biomass and total sugar contentunder different light and temperature conditions were investigated. Using morphological and molecular identification tools,the microalgae were identified as Botryococcus sp. The optimal culture conditions in terms of both the growth and the totalsugar content of Botryococcus sp. were a culture temperature of 28℃ and an illumination intensity of 65 μmol m−2 s−1 inBG11 medium; in its stable stage, the biomass of Botryococcus sp. could reach 0.86 g/L and its total sugar content, 35.6%(dry weight). Total sugar accumulation was positively correlated with the activities of glucose phosphate isomerase andhexokinase, and Botryococcus polysaccharide was composed of L-(+)-rhamnose, D-ribose, D-arabinose, D-xylose, 2-deoxy-D-glucose, D-mannose, D-glucose, D-galactose and N-Acetyl-D-glucosamine.