us4bioma project. Scale up of a novel bioreactor add-on to optimize algal growth and productions via ultrasounds

Algal-based processes are promising, eco-friendly alternative productions of consumer goods, but their spread at large scale is still limited by the cost associated with growth time and yield. Ultrasounds (US) represent a low-energy and scalable technology that may optimize such productions [1-2]. It was previously demonstrated that low-intensity pulsed ultrasound (LIPUS) irradiation in the Sono-photobioreactor (SPBR) enhances biomass production and macromolecule accumulation in green algae [3]. Building on this, the US4BIOMA project aims to scale up the SPBR system to pilot level and apply controlled US cycles to two distinct microalgae species: Chlorella vulgaris and the cell wall-less Dunaliella salina. Algae will be cultivated and treated by pulsed US, while monitoring cell growth and high-value molecules accumulation. To investigate mechanotransduction, transcriptomic analyses will explore the molecular pathways activated by US, while Atomic Force Microscopy will assess changes in cell ultrastructure and turgor. Data collected at lab scale, in silico computation and hydrophone sampling will drive the scale-up of the SPBR to pilot scale. This project not only aims to investigate cell response to US in terms of structure and transcripts but also represents a proof of concept of technologies based on US delivery and their potential of integration into production systems.