Environmental Impacts of Experimental Production of Lactic Acid for Bioplastics from Ulva spp.

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.