The integrated evaluation of the valorization of wine lees to produce value-added products was carried out in this study from a life-cycle perspective. The consumption of steam has been demonstrated as the main hot spot, reaching 85.7% of the impact on Fossil Depletion and 85.3% on Climate Change. Bearing in mind that four different value-added products are produced, a sensitivity analysis was carried out in order to ascertain the influence of the functional unit and the allocation method on the environmental outcomes. The performance of this system was compared to other processes that produce antioxidants from different raw materials. These processes were phycocyanin recovery from Spirulina platensis cyanobacterium, the production of the red antioxidant astaxanthin by microalgae and the valorization of the macroalgae Sargassum muticum. Wine lees valorization showed a better environmental profile throughout the entire life cycle, due to the fact that most of the operations performed are physical (solid/liquid separations, distillations, evaporations, etc.) and do not involve a large consumption of electricity or chemicals. However, there is still room for improvement, and future research should focus on optimizing the extraction of antioxidants from wine lees using two-stages aqueous systems, ultrasonic or microwave assisted extraction, in the pursuit of better performance and lower environmental impact.
Keywords: Biorefinery; Environmental assessment; Life Cycle Inventory; Value-added products; Wine lees valorization.
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