Ultrasound-Based Recovery of Anti-Inflammatory and Antimicrobial Extracts of the Acidophilic Microalga Coccomyxa onubensis

In the present study, the recovery of valuable molecules of proven anti-inflammatory and antimicrobial activity of the acidophilic microalga Coccomyxa onubensis (C. onubensis) were evaluated using green technologies based on ultrasound-assisted extraction (UAE). Using a factorial design (3 x 2) based on response surface methodology and Pareto charts, two types of ultrasonic equipment (bath and probe) were evaluated to recover valuable compounds, including the major terpenoid of C. onubensis, lutein, and the antimicrobial activity of the microalgal extracts obtained under optimal ultrasound conditions (desirability function) was evaluated versus conventional extraction. Significant differences in lutein recovery were observed between ultrasonic bath and ultrasonic probe and conventional extraction. Furthermore, the antimicrobial activity displayed by C. onubensis UAE-based extracts was greater than that obtained in solvent-based extracts, highlighting the effects of the extracts against pathogens such as Enterococcus hirae and Bacillus subtilis, followed by Staphylococcus aureus and Escherichia coli. In addition, gas chromatography-mass spectrometry was performed to detect valuable anti-inflammatory and antimicrobial biomolecules present in the optimal C. onubensis extracts, which revealed that phytol, sterol-like, terpenoid, and even fatty acid structures could also be responsible for the antibacterial activities of the extracts. Moreover, UAE displayed a positive effect on the recovery of valuable molecules, improving biocidal effects. Our study results facilitate the use of green technology as a good tool in algal bioprocess engineering, improving energy consumption and minimizing environmental impacts and process costs, as well as provide a valuable product for applications in the field of biotechnology.

Automated summary

This study evaluated the recovery of valuable molecules with anti-inflammatory and antimicrobial activity from the acidophilic microalga Coccomyxa onubensis using green technologies based on ultrasound-assisted extraction (UAE). Significant differences in extraction recovery were observed between ultrasonic bath, ultrasonic probe, and conventional extraction. UAE-based extracts exhibited higher antimicrobial activity compared to solvent-based extracts.