The present invention relates to a procedure for the obtainment of fatty acids of pharmacological and nutritional interest comprising the stages of feeding a gas comprising CO into a rector containing a crop comprising at least one species of microalgae capable of realising photosynthesis, realisation of the process of photosynthesis by the species of microalgae from the CO feed, producing a biomass containing a compound of general formula (I), extraction of the compound of general formula (I) from the biomass, and concentration and/or purification of said compound.
