Beyond phycocyanin: Environmental life cycle assessment of a European pilot scale Spirulina biorefinery

Abstract

The cyanobacterium Arthrospira platensis (or Spirulina) naturally synthesises phycocyanin, a blue pigment used in food and cosmetics. From 2018 to 2023, the European “SpiralG” project revisited its value chain to convert the residual biomass from phycocyanin extraction into valuable food, feed, cosmetic, and agricultural ingredients. This study presents a cradle-to-gate environmental life cycle assessment (LCA) of the pilot-scale biorefinery, producing 10 metric tons of Spirulina biomass and 8 metric tons of food-grade phycocyanin annually. The LCA results identify cultivation and drying of Spirulina as the main contributors to the biorefinery's environmental impacts. Technological improvements reduced climate impacts by 14 % from the start to the end of the project, including optimised nutrient use, advanced processing techniques, and waste energy recovery. Despite these improvements, the use of electricity from the national grid and mineral fertilisers remain major contributors to environmental impacts. To address these challenges, three mitigation strategies are proposed: coupling Spirulina cultivation with anaerobic digestion to use digestate as a source of organic nitrogen, co-locating all process stages to leverage geographical advantages, and using renewable energy for biomass processing. This work constitutes the first LCA study of a pilot-scale Spirulina biorefinery using real operational data. We underscore the importance of transparent, open-source methodologies and provide valuable insights for developing sustainable microalgal biorefineries. The findings support future development strategies and align with the European Union's objectives for promoting a circular and blue bioeconomy, laying the groundwork for optimising high-value algae-based products while minimising environmental impacts. • Processing Spirulina biomass into food, feed, cosmetic, and agricultural products • Cultivation and drying identified as key environmental hotspots in the biorefinery • 14 % reduction in climate impacts due to technological advancements • Improved transparency and reproducibility in LCA through open-source data

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