Abstract

Fish oil has been used in conventional aquaculture for decades, despite the known links between increasing global demand for fish and depletion of natural resources and vital ecosystems (FAO, 2020, 2019). Alternative feed ingredients, including algae oil rich in docosahexaenoic acid (DHA), has therefore been increasingly used to substitute traditional fish oil. Heterotrophic algae cultivation in bioreactors can be supported by a primary carbon feedstock recovered from food waste, a solution that could reduce environmental impacts and support the transition towards circular food systems. This study used life cycle assessment to quantify environmental impact of DHA produced by the heterotrophic algae Crypthecodinium cohnii, using short-chain carboxylic acids derived from dark fermentation of food waste. The future potential of DHA from algae was evaluated by comparing the environmental impact to that of DHA from Peruvian anchovy oil. With respect to global warming, terrestrial acidification, freshwater eutrophication and land use, algae oil inferred -52 ton CO2eq, 3.5 ton SO2eq, -94 kg Peq, 2700 m2 eq, respectively per ton DHA. In comparison, the impact per ton DHA from fish oil was -15 ton CO2eq, 3.9 ton SO2eq, -97 kg Peq and 3200 m2 eq. Furthermore, algae oil showed lower climate impact compared to canola and linseed oil. By including Ecosystem damage as indicator for ecosystem quality at endpoint level, the important aspect of biodiversity impact was accounted for. Although the method primarily accounts for indirect effects on biodiversity, DHA from algae oil showed lower Ecosystem damage compared to fish oil even when future energy development, optimized production, increased energy demand and effects on biotic resources were considered via sensitivity analyses. As the results suggest, algae oil holds a promising potential for increased sustainability within aquaculture, provided that continued development and optimization of this emerging technology is enabled through active decision-making and purposeful investments.

Keywords

life cycle assessment (LCA); volatile fatty acids (VFA); docosahexaenoic acid (DHA); biodiversity; food waste

Published in

Sustainable Production and Consumption
2021, Volume: 27, pages: 2002-2021

SLU Authors

• Bartek, Louise

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

• Strid, Ingrid

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

• Henryson, Kajsa

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

• Eriksson, Mattias

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

Associated SLU-program

Food Waste


Sustainable Development Goals

End hunger, achieve food security and improved nutrition and promote sustainable agriculture
Ensure sustainable consumption and production patterns


UKÄ Subject classification

Fish and Aquacultural Science


Publication identifier

DOI: https://doi.org/10.1016/j.spc.2021.04.033

Permanent link to this page (URI)

https://res.slu.se/id/publ/111936