Sub- and supercritical fluid extraction of bioactive compounds from plants, food-by-products, seaweeds and microalgae – An update

What if we could squeeze every drop of value from microscopic algae without harming the planet? Scientists are turning to high-pressure green chemistry to find out.

As the push for biorefinery approaches gathers momentum, researchers are hunting for smarter, greener ways to process biomass. Enter *Porphyridium cruentum*, a microscopic powerhouse packed with valuable treasures like carotenoids, phycoerythrin, and sulfated polysaccharides. But how do you harvest these delicate compounds efficiently?

Recent work explores compressed fluid-based techniques to unlock this microalgal biomass. By putting pressurized ethanol to the test, scientists optimized carotenoid extraction, hitting the sweet spot at 125 °C and 20 min under 10.5 MPa.

Building on this success, the team devised a clever sequential valorization process. Instead of a single harvest, they stepped through targeted phases to recover phycoerythrin, sulfated polysaccharides, and carotenoids in an orderly fashion. Crucially, these pressurized conditions delivered a strong recovery of polar components while keeping the carotenoids stable and intact. It is a harmonious, green pathway to extracting multiple bioactives from a single microalgal source.

Key Points

• Optimized carotenoid extraction using pressurized ethanol at 125 °C
• Sequential process targeting phycoerythrin and sulfated polysaccharides
• Green extraction achieving good recovery without compromising stability