Modelling growth and CO2 fixation by Scenedesmus vacuolatus in continuous culture

A promising approach to CO2 abatement is the use of photosynthetic microorganisms. Different microalgae (Chloroccocum sp., Porphyridium purpureum, Scenedesmus vacuolatus) and cyanobacteria (Anabaena PCC7119, Anabaena PCC7120, Anabaena PCC 7937, Nostoc PCC 9202, Nostoc punctiforme) were cultivated in photobioreactors operated as chemostat, simulating light conditions analogous to those prevailing outdoors and compared on their ability to fix CO2 efficiently. Due to its high biomass productivity and CO2 fixation rate, Scenedesmus vacuolatus was selected and the effect of different culture parameters (i.e. dilution rate, temperature, pH and impinging irradiance on surface's photobioreactor) on its biomass productivity and CO2 fixation was further investigated. In optimal culture conditions, S. vacuolatus rendered 0.63 g biomass L− 1 d− 1, resulting 1.15 gCO2 assimilated L− 1 d− 1. Based on the data obtained in this study, a mathematical model was developed to describe growth and CO2 bio-fixation by S. vacuolatus. Finally, the potential of this microalga for carbon capture was further tested using synthetic flue gases as the source of CO2.