Conversion of CO2 into biomass by microalgae: how realistic a contribution may it be to significant CO2 removal?

Microalgae have been proposed as a CO2 removal option to contribute to climate change avoidance and problems coming from the use of fossil fuels. However, even though microalgae can be used to fix CO2 from air or flue gases, they do not permit long-term CO2 storage because they are easily decomposed. On the other hand, microalgae can contribute to an enhancement in human sustainability by producing biofuels as an alternative to fossil fuels in addition to the production of other useful chemicals and commodities. Moreover, microalgae can contribute to enhancing the sustainability of waste treatment processes, reducing the energy consumed, and improving the recycling of nutrients contained within them. This paper reviews the potential contribution of these processes and the existing knowledge in these areas.