Selective Extraction of Fatty Acids and Carotenoids from Microalgae

Significance of the Topic

Microalgae such as Spirulina maxima are prized for their high carotenoid content, which offers antioxidant benefits and serves as a source of vitamin A. Extraction of these compounds is critical for applications in food, cosmetics and pharmaceuticals. Traditional solvent-based methods are laborious, generate hazardous waste and yield complex mixtures that complicate downstream purification. Supercritical fluid extraction (SFE) using CO2 offers a greener, faster and more selective alternative.

Objectives and Study Overview

This study aimed to develop a targeted SFE protocol to isolate carotenoids and fatty acids from dry Spirulina maxima biomass. Key goals included minimizing co-extraction of undesired lipids (triglycerides), reducing solvent use, and demonstrating improved extract purity and processing efficiency compared to conventional methods.

Methodology

The procedure involved conditioning 8 g of dried, ground Spirulina maxima in a 10 mL extraction vessel. SFE parameters were optimized to balance yield and selectivity:

• Pressure: 150 bar
• Temperature: 50 °C
• CO2 flow rate: 3 L/min (gas)
• Dynamic extraction time: 60 min
• Valve temperature: 100 °C
• Depressurization time: 20 min

Samples were collected in pre-weighed vials to determine extract mass and composition.

Instrumentation

The extraction system used was the Applied Separations Spe-ed™ SFE or Helix Supercritical Extraction System. Quantitative and qualitative analysis of extracts employed UV–visible spectrophotometry to track carotenoid absorbance and GC-MS for detailed fatty acid profiling.

Main Results and Discussion

Supercritical CO2 extraction under the chosen conditions achieved selective recovery of carotenoids and fatty acids with negligible triglyceride co-extraction. Extracts displayed strong UV absorbance in the carotenoid region and a fatty acid profile consistent with literature values. The absence of organic solvents simplified fractionation and reduced sample handling risks.

Benefits and Practical Applications

• Elimination of toxic organic solvents enhances operator safety and environmental compatibility
• Selective extraction reduces downstream purification steps, cutting processing costs
• Adaptable to different microalgal species and scalable for industrial production

Future Trends and Opportunities

Advances may include inline process monitoring, automated fraction collection and the use of co-solvents or modifiers to fine-tune selectivity. Integration of continuous SFE modules with real-time analytics and expansion to other high-value algal metabolites will further broaden industrial applications.

Conclusion

The study confirms that supercritical CO2 extraction is a viable, eco-friendly alternative to traditional solvent methods for isolating carotenoids and fatty acids from Spirulina maxima. It delivers high purity extracts, reduces hazardous waste and presents a scalable solution for commercial exploitation.

References

• Canela A, Rosa P, Marques M, Meireles M. Supercritical Fluid Extraction of Fatty Acids and Carotenoids from the Microalgae Spirulina maxima. Ind Eng Chem Res. 2002;41(12):3012–3018.