Continuous Microalgal Cultivation for Antioxidants Production

Area of Science:

• Biotechnology
• Marine Biology
• Natural Products Chemistry

Background:

• Microalgae and cyanobacteria are rich sources of bioactive compounds with antioxidant properties.
• Antioxidant profiles vary significantly between microalgal species.
• Optimizing cultivation conditions is crucial for maximizing antioxidant yields.

Purpose of the Study:

• To evaluate the antioxidant content and productivity of four microalgae species.
• To compare biomass productivity in batch versus continuous cultures.
• To identify specific antioxidant compounds produced by each microalga.

Main Methods:

• Cultivation of four microalgae species (Spirulina platensis, Isochrysis galbana, Tetraselmis suecica, Porphyridium cruentum) in batch and continuous photobioreactor systems.
• Assessment of biomass productivity and energetic yield.
• Analysis of antioxidant compounds including phenols, terpenoids, alkaloids, tocopherols, carotenoids, phycocyanin, and allophycocyanin.

Main Results:

• Continuous cultivation increased microalgal biomass productivity by 5.9 to 6.3 times compared to batch cultures.
• Energetic yield ranged from 0.03 to 0.041 g biomass kJ⁻¹.
• Specific antioxidants like phenols, terpenoids, and alkaloids were identified in T. suecica, I. galbana, and S. platensis, while tocopherols and carotenoids were common across all four species. Phycocyanin and allophycocyanin were exclusively found in S. platensis and P. cruentum.

Conclusions:

• Continuous cultivation in photobioreactors is an effective strategy for enhancing microalgal biomass and antioxidant production.
• The choice of microalga species and cultivation method significantly impacts the type and quantity of antioxidants produced.
• This study highlights the potential of optimized microalgal cultivation for sustainable production of natural antioxidants.