Life cycle assessment of bioenergy and value-added biochemical production from Nizimudinia zanardini brown macroalgae

Abstract

This study aimed to contribute to the sustainable development of the Blue Bioeconomy via cascade biorefineries of macroalgae by investigating the environmental sustainability of two algae-biorefinery systems that utilize endemic brown macroalgae Nizimuddinia zanardini. The first scenario involved the production of fuel ethanol, and electricity, while the second scenario included the co-production of fuel ethanol, electricity, and high-value bio-based chemicals, i.e., protein, mannitol, and alginate. Combining process simulation tools with consequential life cycle assessment, the study provides a comprehensive evaluation of the environmental impacts associated with the valorization of 1 metric ton of dry algae considering three areas of environmental protection namely human health, ecosystem quality, and resource depletion. The results demonstrated that the biorefinery approach led to net savings of −2.61 × 10−3 DALYs, −1.18 × 10−5 species.yr, and − 76.8 USD2013 per ton of macroalgae on human health, ecosystem quality, and resource depletion, respectively. Conversely, the only-fuel approach resulted in a net savings of −74.6 USD2013 per ton of macroalgae on resource depletion, and the net impact of 2.14 × 10−4 DALYs, 5.33 × 10−7 species.yr per ton of macroalgae on human health, and ecosystem quality, respectively. In general, the biorefinery approach compared to the only-fuel approach led to significant savings in all damage categories owing to the generation of high-value products. These findings highlight the significant potential of biorefineries for the sustainable valorization of macroalgae. © 2025 Elsevier B.V.