A Modeled High-Density Fed-Batch Culture Improves Biomass Growth and β-Glucans Accumulation in Microchloropsis salina

Algae and microalgae are used as a source of different biomolecules, such as lipids and carbohydrates. Among carbohydrates, polysaccharides, such as β-glucans, are important for their application as antioxidants, antisepsis, and immunomodulators. In the present work, the β-glucans production potential of Microchloropsis salina was assessed using two different culture conditions: a high-density batch and a modeled high-density fed-batch. From the biochemical parameters determined from these two cultures conditions, it was possible to establish that the modeled high-density fed-batch culture improves the biomass growth. It was possible to obtain a biomass productivity equal to 8.00 × 10^-2 ± 2.00 × 10^-3 g/(L × day), while the batch condition reached 5.13 × 10^-2 ± 4.00 × 10^-4 g/(L × day). The same phenomenon was observed when analyzing the β-glucans accumulation, reaching volumetric productivity equal to 5.96 × 10^-3 ± 2.00 × 10^-4 g of product/(L × day) against the 4.10 × 10^-3 ± 2.00 × 10^-4 g of product/(L × day) obtained in batch conditions. These data establish a baseline condition to optimize and significantly increase β-glucan productivity, as well as biomass, adding a new and productive source of this polymer, and integrating its use in potential applications in the human and animal nutraceutical industry.