From Seaweed Biorefinery to Bioplastics: A Life Cycle Analysis of Energy Use and Environmental Impacts

This study assesses the environmental performance of a seaweed-derived Bioplastic film through a cradle-to-gate life cycle assessment of production from Saccharina latissima. The system includes hatchery, marine cultivation, pretreatment, crude extraction, cross-linking, casting, and drying, with a functional unit of 1 kg of dry film. The total climate change impact is 3.79 kg of CO2-eq/kg of dry film, dominated by cross-linking (47%) and cultivation (29%), identifying cross-linking as the primary hotspot across multiple impact categories. Pretreatment and extraction generate substantial wastewater, and the associated treatment burdens are driven largely by sodium hydroxide production and electricity use, underscoring the need for improved treatment strategies. Compared with low-density polyethylene, seaweed bioplastics exhibit slightly higher climate impacts but lower fossil resource scarcity, alongside higher water use and ecotoxicity. Scenario analysis shows that improving the wet-to-dry conversion efficiency can reduce climate impacts by up to 22%. Moreover, seaweed bioplastics reduce reliance on fossil resources but present notable environmental trade-offs, emphasizing the need for process improvements, particularly in cross-linking, drying, and the use of lower-impact or alternative neutralization agents.