Development of nitrogen supply strategy for Scenedesmus rubescens attached cultivation toward growth and lipid accumulation.

In this study, the microalgae Scenedesmus rubescens were cultivated under the following nitrogen sources, nitrogen concentrations, and nitrogen feeding times (NFTs). This was to help assess biomass and lipid productivity. Scenedesmus rubescens can grow well by adhering to the cellulose acetate membrane in five kinds of nitrogen medium: KNO3 , urea, NaNO3 , (NH4 )2 CO3 , and NH4 NO3 . Under the criteria of bio-productivity and lipid productivity, urea was the optimal nitrogen source. Among different urea concentrates, biomass productivity and lipid content of S. rubescens cultivated in 0.27 g/L urea medium were optimized at 8.8 g/(m2  day) and 31.1%, respectively. With attached cultivation, the highest biomass of 9.4 g/m2 was obtained at NFTs of 4 days. These results showed that culturing S. rubescens using urea as sole nitrogen source by improving nitrogen uptake with attached cultivation is more efficient.