Environmental profiling microalgae-based eicosapentaenoic acid production along the technical advancement via life cycle assessment

Abstract

Microalgae have attracted attention from various fields due to their potential ability to accumulate diverse value-added products, including polyunsaturated fatty acids (PUFAs). Many approaches have been used to enhance the productivity of microalgae-based PUFAs, such as eicosapentaenoic acid (EPA), but in many cases, these have only focused on economic competitiveness. However, it is imperative to simultaneously quantify and optimize the associated environmental impact at an early stage to guide future developments and sustainable scale-up. This study conducted Life Cycle Assessments (LCA) along the technical advancements of laboratory-scale EPA production by Phaeodactylum tricornutum. Results indicated that technical advancements enhanced the environmental performance associated with EPA production. Among these, metabolic engineering led to the most significant reductions (93.48% and 93.45%) in terms of global warming potential and cumulative energy demand compared with the wild-type scenario due to elevated microalgal growth and EPA yield. Electricity consumption remained the dominant contributor to the associated environmental impact, followed by extraction solvents, especially chloroform. In terms of processes, cultivation of the microalgae and harvesting of the biomass accounted for the majority of the impact attributed to the long cultivation period and the energy-intensive processes such as freeze drying. As guided by the sensitivity analysis, future directions should focus on further increasing EPA productivity, adopting alternative cultivation approaches with less energy input, and recovering EPA via environmentally friendly methods.