A life cycle environmental sustainability analysis of microbial protein production via power-to-food approaches

Purpose: Renewable energy produced from wind turbines and solar photovoltaics (PV) has rapidly increased its share in global energy markets. At the same time, interest in producing hydrocarbons via power-to-X (PtX) approaches using renewables has grown as the technology has matured. However, there exist knowledge gaps related to environmental impacts of some PtX approaches. Power-to-food (PtF) application is one of those approaches. To evaluate the environmental impacts of different PtF approaches, life cycle assessment was performed. Methods: The theoretical environmental potential of a novel concept of PtX technologies was investigated. Because PtX approaches have usually multiple technological solutions, such as the studied PtF application can have, several technological setups were chosen for the study. PtF application is seen as potentially being able to alleviate concerns about the sustainability of the global food sector, for example, as regards the land and water use impacts of food production. This study investigated four different environmental impact categories for microbial protein (MP) production via different technological setups of PtF from a cradle-to-gate perspective. The investigated impact categories include global warming potential, blue-water use, land use, and eutrophication. The research was carried out using a life cycle impact assessment method. Results and discussion: The results for PtF processes were compared with the impacts of other MP production technologies and soybean production. The results indicate that significantly lower environmental impact can be achieved with PtF compared with the other protein production processes studied. The best-case PtF technology setups cause considerably lower land occupation, eutrophication, and blue-water consumption impacts compared with soybean production. However, the energy source used and the electricity-to-biomass efficiency of the bioreactor greatly affect the sustainability of the PtF approach. Some energy sources and technological choices result in higher environmental impacts than other MP and soybean production. When designing PtF production facilities, special attention should thus be given to the technology used. Conclusions: With some qualifications, PtF can be considered an option for improving global food security at minimal environmental impact. If the MP via the introduced application substitutes the most harmful practices of production other protein sources, the saved resources could be used to, for example, mitigation purposes or to improve food security elsewhere. However, there still exist challenges, such as food safety–related issues, to be solved before PtF application can be used for commercial use.