Recent Advances in NADES-Assisted Process Intensification Technologies for Sustainable Recovery of Microalgal Bioactives: Challenges and Future Prospectives

Microalgae are tiny green factories with a big secret: they can produce valuable bioactive compounds—but only if we can crack their tough cell walls without burning the planet. Now, a new class of solvents called NADES is stepping into the spotlight, promising a greener path to unlock these treasures.

Imagine tiny algae that could power our medicines, cosmetics, and foods—if only we could get inside them. Their rigid cell walls and complex metabolite mixtures have long made industrial extraction a costly, energy-hungry affair. But recent advances in process intensification—using microwaves, ultrasound, enzymes, pressurized liquids, and supercritical CO2—are changing the game. These methods dramatically boost efficiency, with lipid recoveries exceeding 40-50% in some systems and carotenoid recoveries nearing 90% under optimized conditions.

Enter NADES, or Natural Deep Eutectic Solvents. These designer solvents form hydrogen bonds with target molecules, enhancing mass transfer and solubilization. This allows selective extraction of polar and semi-polar metabolites under mild conditions, reducing energy demands.

However, NADES are not without challenges. Their high viscosity can hinder performance, and variability in extraction results remains a concern. Solvent recovery and scale-up are also tricky hurdles.

This review critically evaluates the efficiency, mechanisms, and sustainability of NADES-assisted processes, highlighting key limitations and research priorities. The goal: integrating NADES into scalable microalgal biorefineries for a truly sustainable bioeconomy.

Key Points

• NADES-assisted extraction boosts lipid recovery >40-50% and carotenoids ~90%.
• NADES enable selective, mild extraction via hydrogen-bonding interactions.
• Challenges: high viscosity, variable performance, recovery, and scale-up.