[en] Microalgae are considered as a promising source of bio-based energy thanks to their high photosynthetic rates and their rapid growth compared to terrestrial plants, high lipid content, low surface area demand and year-round cultivation. Nevertheless, life-cycle assessment for production of interesting products like biodiesel from microalgae cultivation have shown that the production of biomass needs to be coupled with some other aspects: the valorisation of microalgal high-value-added by-products (antioxidants, protein and/or polysaccharide contents), the CO2 mitigation and the use of other industrial waste streams1.
This is why industrial flue gases are a propitious source of carbon and other nutrients for the microorganisms2,3. In such an industrial process, some components of the flue gas (mainly CO2 and SO2) are transferred into the culture medium and form dissolved CO2 and SO2 as well as (hydrogen)-carbonates and (hydrogen)-sulphites. The latter are then oxidised by oxygen to form sulphates. Sulphates and (hydrogen)-carbonates are nutrients for the culture, but some authors have shown that hydrogen sulphites can inhibit microalgal growth4,5.
The first objective of this work was to determine the composition of Scenedesmus dimorphus's culture medium (3N-BBM medium) at equilibrium with a synthetic cement plant flue gas. According with the equilibrium compositions, three sulphite stresses were performed on S. dimorphus cultures in order to evaluate the impact of the sulphite anions on cell growth and biochemical composition (proteins, polysaccharides and lipids).
