The idea is to ‘hit two targets with one shot’; that is, to produce energy while decontaminating industrial sites. But how? By introducing certain effluents, such as carbon dioxide (CO₂) or nitrogen oxides (NOx) in the microalgae culture media. Large-scale production of microalgae could thus absorb 1.83 tons of CO₂ and around 150 kg of NOx per ton of biomass produced. Nitric oxide (NO) is a powerful greenhouse gas, notably responsible for acid rain. It is also a signaling molecule in living organisms: in animals, NO is a vasodilator and plays a role in the immune response; in plants, NO is involved in the responses to oxidative stress and pathogens. This molecule is also metabolized by microalgae during their growth, by mechanisms that remain largely unknown.

A joint symposium held in Halifax, Canada in October 2012 has already resulted in the implementation of a first collaborative project. The French and Canadian researchers plan to study the effect of NOx on the growth and metabolism of microalgae. After having determined toxicity thresholds in several species, the scientists will analyze the assimilative capacity of microalgae to those doses that they tolerate. They will use molecular, metabolomic and physiological approaches to study the mechanisms involved.