Sono-photobioreactor: Design and application of characterized and modulable reactor to optimize microalgal production with ultrasounds

Microalgae are considered efficient cell chassis to produce valued bio-products, but their spread is hampered by the sustainability of biomass production. In this work, a novel tool for ultrasound irradiation during algae cultivation was designed: the sono-photobioreactor. Computational characterization allowed reproducible and precise ultrasound treatment of two commercially relevant microalgae. Data showed a different response between the two algae and among treatments. Ultrasound power density positively correlated to biomass, that reached 1.2 g/L in Chlorella vulgaris (vs 1.0 of control) and 2.3 g/L in Desmodesmus sp. (vs 1.9 of control). Lower power density doubled proteins in Desmodesmus sp., 40 % dry weight (vs 20 % of control) and increased carbohydrates in Chlorella vulgaris, 19 % dry weight (vs 9 % of control). Results showed that the ultrasound device, here proposed, is a promising tool that can be easily integrated in conventional photobioreactors in order to optimize microalgae-based bioprocesses.