Prediction of the environmental impacts of yeast biodiesel production from cardoon stalks at industrial scale

The study aims to develop a full-scale plant to produce yeast biodiesel from cardoon stalks, based on the biorefinery concept, and to evaluate its environmental burden using a cradle-to-gate, scaled-up LCA approach. The results identified the following environmental hotspots all over the whole chain: the production of enzymes required in the hydrolysis of steam-exploded biomass and the heat and organic solvents required for lipid extraction and the subsequent distillation steps. The analysis of the LCA normalization results revealed that the highest environmental burdens were associated with human carcinogenic toxicity (69.2%). A further interesting result was that the GHG emissions associated to yeast biodiesel are negative (−1.5 g CO2 eq/MJ), due to the environmental credits generated by the co-products. Comparison with other biodiesel sources were also carried out showing that yeast biodiesel from cardoon stalks has the potential to become a competitive alternative from an environmental perspective.