Carbon dioxide fixation and lipid storage by Scenedesmus obtusiusculus.

An indigenous microalga was isolated from the springs in Cuatro Ciénegas, México. It was morphologically identified as Scenedesmus obtusiusculus and cultivated in bubble-column photobioreactors in batch operation mode. This microalga grows at 10% of carbon dioxide (CO(2)) showing a maximum CO(2) fixation rate of 970gm(-3)d(-1). The microalga, without any nutrient limitation, contained 20% of nonpolar lipids with a biomass productivity of 500gm(-3)d(-1) and a maximum biomass concentration of around 6,000gm(-3) at 5% CO(2) and irradiance of 134μmolm(-2)s(-1). Furthermore, it was observed that the microalga stored 55.7% of nonpolar lipids when 5% CO(2) was fed at 0.8vvm and 54.7μmolm(-2)s(-1) under nitrogen starvation. The lipid profile included C16:0, C18:0, C18:1n9t, C18:1n9c, C18:3n6 with a productivity of 200g lipid m(-3)d(-1). Therefore, the microalga may have biotechnological potential producing lipids for biodiesel.