Scenedesmus rubescens Heterotrophic Production Strategies for Added Value Biomass

Abstract

Microalgae attract interest worldwide due to their potential for several applications. Scenedesmus is one of the first in vitro cultured algae due to their rapid growth and handling easiness. Within this genus, cells exhibit a highly resistant wall and propagate both auto- and heterotrophically. The main goal of the present work is to find scalable ways to produce a highly concentrated biomass of Scenedesmus rubescens in heterotrophic conditions. Scenedesmus rubescens growth was improved at the lab-scale by 3.2-fold (from 4.1 to 13 g/L of dry weight) through medium optimization by response surface methodology. Afterwards, scale-up was evaluated in 7 L stirred-tank reactor under fed-batch operation. Then, the optimized medium resulted in an overall productivity of 8.63 g/L/day and a maximum biomass concentration of 69.5 g/L. S. rubescens protein content achieved approximately 31% of dry weight, similar to the protein content of Chlorella vulgaris in heterotrophy.

Response and Resilience of Scenedesmus rubescens Microalgae to ZnO Nanoparticles

“…Other studies [15,28] have also reported the resistance of S. rubescens to NP exposure. It is possible that the morphological characteristics of this genus, such as its highly resistant cell walls [19], could be among the parameters impacting its behavior. Many species of microalgae are resistant to nanoparticles, especially at low nanoparticle concentrations, and nanoparticles have even been used in order to trigger an increase in biomass concentration and lipid content [29].…”

“…In this study, focus was put on Scenedesmus rubescens, a green microalga that is globally present in freshwater and wastewater [19] and has been used in novel industrial applications like biodiesel production [20]. S. rubescens is used as a model species for toxicity since it is found to be resistant to toxic effects induced by the presence of NPs and to exhibit minimal or even no growth inhibition [15].…”