Systemaattinen kirjallisuuskatsaus kemotrofisten yksisoluisten proteiinien tuotannon ympäristövaikutuksista

The global food system is a major transgressor of planetary boundaries. With the increasing and ageing population, the demand for protein will continue to grow. Alternative proteins play a crucial role in meeting this demand while decreasing the environmental impacts of the global food system. Chemotrophic single-cell protein is one example of alternative proteins, produced from microorganisms that cannot utilise sunlight as their primary source of chemical energy. This thesis aims to assess the status of research in the environmental impacts of chemotrophic single-cell protein production, as well as compare them with each other. Systematic literature review was conducted for the thesis and resulted in thirteen included articles. Findings and features of the included articles were reported, and a comparative attributional life cycle assessment was conducted for nine of the included articles. The number of articles assessing the environmental impacts of chemotrophic single-cell protein is small and focuses on a limited variety of species of microorganism. Bacteria based single-cell proteins have generally higher environmental impacts compared to fungi. Fermentation and enrichment stages of production cause the highest relative impacts regardless of microorganism. More life cycle assessments of chemotrophic single-cell protein production should be conducted, so a more comprehensive comparison is facilitated. Life cycle assessments play a crucial role in early development of alternative protein production systems.