Title : Microalgal protein as a sustainable source of protein: Optimization of alkali extraction
Abstract:
Microalgae and yeasts are promising sources of bioactive compounds such as pigments and lipids, which have diverse applications in nutrition, pharmaceuticals, cosmetics, and other industries. However, the extraction of these valuable compounds is often hindered by their susceptibility to degradation during conventional extraction processes. Traditional methods, including Folch extraction, rely on chlorinated solvents that pose environmental and health risks, while techniques like Soxhlet extraction can induce thermal degradation of sensitive molecules due to repeated heating cycles. This study investigates the feasibility and effectiveness of supercritical fluid extraction (SFE) using carbon dioxide, with the optional addition of ethanol as a co-solvent, as a greener and potentially more efficient alternative for isolating lipids and pigments from various microalgae and yeast strains.
The SFE approach offers several advantages, including rapid extraction, the use of non-toxic and environmentally benign solvents, and reduced degradation of thermolabile bioactive compounds. In this work, we systematically compared the yield and composition of pigments and lipids obtained via SFE with those extracted by conventional methods. Quantitative and qualitative analyses were performed to assess not only the total amount of extracted compounds but also their integrity and antioxidant activity, which serve as indicators of preservation of bioactivity.
Our results demonstrate that SFE enables gentler extraction conditions, resulting in lower degradation rates of sensitive compounds and enhanced antioxidant properties of the extracts. The comparative analysis highlights the potential of SFE to optimize extraction protocols for microalgae and yeast bioprocessing. These findings support the development of high-value products with tailored functional attributes and contribute to advancing sustainable practices in the extraction of bioactive compounds from microorganisms.
Key words: Supercritical fluid extraction, lipids, pigments, sustainable extraction
