Recent advances in the scale-up of microalgae production systems

Abstract of an oral presentation at ISAP 2024, Porto, Portugal. The most relevant advances in the scaleup of microalgae production systems are reviewed. Concerning the biological systems, the models recently developed provide a complete overview of phenomena taking place, including the influence of culture conditions, the presence of different microorganisms, and the role of parasites. These models allow to determine the most efficient strategies to optimize their performance as a function of these variables, including the prevention of crashes. The use of computational fluid dynamics allows building units up to 1 ha, while minimizing energy consumption below 5 W/m3, and improving the light utilization efficiency by 25%. The optimization of mass transfer capacity allows for the prevention excess of dissolved oxygen concentrations at the same time optimizing the use of CO2 for pH control, and allowing the direct capture of CO2. Non-pressure membranes allow to pre-concentrate of the cultures at minimum cost/energy consumption while obtaining cell-free supernatants to be recirculated or for safe disposal, while Low-pressure membranes allow to fractionate of the compounds of microalgae biomass without using solvents to achieve sustainable processes with zero emissions. The use of advanced control systems that allow for optimisation of the performance of the cultures/systems as a function of target function and environmental conditions. High-level control strategies based on artificial intelligence are capable of adjusting the operation conditions to optimise the performance of the overall system. All these advances have been already demonstrated and now are applied in industrial facilities, with examples of those applications being provided.