Microalgae Flocculation: Assessment of Extraction Yields and Biological Activity

Area of Science:

• Biotechnology
• Phycology
• Bioprocess Engineering

Background:

• High downstream processing costs hinder microalgae commercialization.
• Developing economical and scalable strategies is crucial for widespread microalgae adoption.

Purpose of the Study:

• To evaluate flocculation as a cost-effective downstream processing method for diverse microalgae strains.
• To assess the impact of flocculation on carotenoid extraction yield and biological activity.

Main Methods:

• Tested various flocculants (CaCl2, chitosan) on different microalgae and cyanobacteria strains.
• Optimized flocculation conditions, including pH adjustment for specific strains.
• Extracted carotenoids from flocculated biomass and evaluated biological activity (antioxidant).

Main Results:

• CaCl2 achieved high flocculation rates for green (96%) and red (87%) marine microalgae.
• Chitosan effectively flocculated cyanobacteria (46%).
• Flocculation maintained carotenoid yield comparable to centrifugation, especially with wet biomass, and enhanced antioxidant activity in green microalgae extracts.

Conclusions:

• Flocculation is a viable, cost-effective alternative to centrifugation for microalgae downstream processing.
• Strain-specific downstream strategies are necessary for optimal microalgae utilization.
• Flocculation does not negatively impact carotenoid yield and can preserve or enhance biological activity.