Exogenous microbubbles contribute to valorization of microalgal compounds by ultrasound-assisted extraction

Ultrasound-assisted extraction (UAE) shows great potential in exploiting microalgal compounds. However, upgrading the extraction system lacks concerns. This study proposes a novel sono-reactor featuring a microbubble distributor for increasing bubble abundance and correspondingly improving microalgal compound extraction. Results indicate that protein concentrations increase with ultrasound powers and extraction time while an optimized gas flow rate exists. The optimal parameters by Box-Behnken design are power 646.0 W, nitrogen flow rate 25.0 mL/min, and time 40.0 min, with an optimal protein concentration of 249.1 mg/L - a substantial improvement over gas-free extraction. The strategic increase in bubble abundance enhances microalgal compound extraction efficiency and extraction kinetics. The system innovation will contribute to the advancement of bioresource utilization and sustainability.