An exploratory Life Cycle Assessment (LCA) was carried out to provide insight into the environmental impacts of using the green seaweed Ulva spp. as a feedstock, for production of bioplastic. The study focused on the production of lactic acid as a precursor of polylactic acid. The study was on the production process: (1) The cultivation of Ulva spp., in an Integrated Multitrophic Aquaculture system; (2) the processing of the biomass for solubilization of sugars; (3) the fermentation of the sugars to lactic acid; (4) the isolation of lactic acid from fermentation broth. The study identified environmental hotspots and compared an experimental seaweed production chain with conventional feedstocks. The main hotspot is derived from electricity consumption during seaweed cultivation. The impact of electricity consumption can be lowered by reducing energy use and sourcing renewable energy, and by improving the material efficiency in the product chain. To improve understanding of the process of production’s environmental impacts, future studies should broaden the system boundaries and scope of sustainability issues included in the environmental assessment.

Plastic waste production increasingly causes environmental pollution. However, end-of-life (EoL) research often lacks detail and timeliness and fails to integrate the end-of-life option into a product’s life cycle in a systemic perspective. This study addresses these knowledge gaps, by applying an improved anticipatory consequential life cycle assessment (LCA) approach. Reuse, mechanical and chemical recycling options were compared for (biobased and fossil-based) high-density polyethylene (HDPE) and polyethylene terephthalate (PET) plastic shampoo bottles in the European context using three types of impact categories: climate change, fossil resource scarcity and mineral resources scarcity. The completeness and detail of EoL were increased by modelling the polymer reprocessing within the collection system including all transport distances, while timeliness was improved by implementing the data applicable for the time of implementation of EoL options in the future. The results show that the reuse option has the largest benefits on climate change impact, and on fossil and mineral resource scarcity for both HDPE and PET, for both biobased and fossil plastics. Furthermore, all EoL options cause a net reduction in all climate change, fossil and mineral resource scarcity thanks to the avoided impact of virgin plastic. Finally, the improved LCA approach, utilized in this study, includes plastic production, use and EoL in one assessment, and thus can provide valuable information for adjusting policy and regulations for plastic manufacturers in their production of new virgin plastic polymer, as it requires alignment with its use and EoL options.