Jump to Main Content
Evaluation of maintenance energy requirements in the cultivation of Scenedesmus obliquus: effect of light intensity and regime
- Sforza, Eleonora, Urbani, Silvia, Bertucco, Alberto
- Journal of applied phycology 2015 v.27 no.4 pp. 1453-1462
- Scenedesmus obliquus, cell growth, energy balance, energy requirements, growth models, irradiation, latitude, light intensity, lipid content, microalgae, photoinhibition
- Most relevant factors influencing microalgae growth are light availability and utilization. In view of maximizing the photosynthetic efficiency of a photobioreactor, the evaluation of maintenance energy is essential to understand the energy requirement for cell growth and it is also a key parameter of most mathematical growth models. In this work, steady-state continuous experiments were carried out in a flat-bed photobioreactor, at different light intensities and irradiation regimes, measuring growth rate, productivity, lipid content, and photosynthetic efficiency of Scenedesmus obliquus at non-limiting N and P condition. Energy balance was applied to measure the maintenance term as a function of irradiation, under both continuous and simulated seasonal irradiation at middle latitudes. The energy requirement for maintenance was found to be greater under high irradiances as a result of the photoinhibition effect. Experimental data were correlated following a substrate inhibition model. The nutrient uptakes were found to depend on growth rate and light intensity and to be affected by the maintenance requirement.