Evaluation of the environmental benefits deriving from the use of waste CO2 for microalgae production in a life cycle perspective.

In the present study the Life Cycle Assessment (LCA) of the cultivation at pilot scale of Phaeodactylum tricornutum for the production of high quality standards bioactive compounds is performed. In particular, microalgae culture is fed with a stream of CO2 considering both the use of synthetic CO2 and waste CO2 from a biogas upgrading process, in order to assess the influence of the CO2 addition on the system environmental performance. The analysis follows the ISO14040 standards and the impact categories recommended in the ILCD Handbook are selected. Preliminary results show that the use of waste CO2 compared to synthetic CO2 allows a significant improvement in the environmental profile of the process, as it does not substantially affect the production of compounds of commercial interest by the alga, allowing instead to avoid the impacts that are linked to the synthetic CO2 production process.