Model-based control of a microalgal bioreactor

Presenter: Hector De la Hoz Siegler

 

 

Microalgae are highly efficient microorganisms with the ability to produce and store large amounts of oil, which can serve as a source of biodiesel. The economic viability of algal bioprocesses, however, is affected by the long doubling times and low cell densities that characterize microalgal cultures. Moreover, the mechanisms controlling oil production and accumulation are not fully understood, and neither is the relationship between growth and oil production. In this work, a mathematical model that represents algal metabolism is proposed, and integrated into an open loop optimal controller that was aimed to maximize biomass productivity in fed-batch cultures. The proposed model satisfactorily correlates the extracellular nitrogen and carbon source concentrations with intracellular nitrogen and oil content, as well as total biomass concentration. The model was used to predict optimal feed strategies to the bioreactor, allowing the biomass and oil productivity to be increased several times.