Cultivation of scenedesmus sp. using optimized minimal nutrients and flocculants - a potential platform for mass cultivation.

A major constraint in the microalgal technology is the economics involved in cultivation and harvesting. This work is focussed on the optimization of nutrients for cultivation and harvesting using 'Scenedesmus sp'. Response surface methodology (RSM) using 'Face centered central composite design' (FCCD) available in Design expert 10.0.4 was used to develop the regression model for optimization of nutrients and flocculation conditions. The optimum nutrient conditions were 500 ppm of urea, 250 ppm of potassium dihydrogen phosphate and 1000 ppm of potassium hydrogen carbonate under artificial light conditions and 500 ppm of urea and 2000 ppm of potassium hydrogen carbonate under sunlight conditions. The optimum conditions were predicted using the model and compared with experimental data. The model has an R2 value of 0.9769 and 0.9798 for artificial light and sunlight conditions, respectively. In the case of harvesting studies, 98% flocculation efficiency was obtained for a combination of pH 10.4, temperature 45°C, 200 mg/l of leaf powder of Cassia auriculata. The model has an R2 value of 0.9989. The present studies indicated that cultivation of Scenedesmus sp. with the optimized nutrients and harvesting conditions facilitate a platform for energy efficient mass cultivation.