Järviö, Natasha
(Helsingin yliopisto, 2022)
Advancements in agriculture and increases in the human population have led to a surge in agricultural and aquacultural production. This increase in production has come at a cost. The consequences of current food production for the environment have never been so pronounced in human history, threatening the relatively stable state in which the Earth system has remained over the past 11,700 years of the Holocene epoch. Intensive farming systems often rely heavily on external inputs such as pesticides, herbicides and fertilizers to suppress the natural process of species diversification on the land, which lead to problems such as eutrophication, soil exhaustion and desertification. Other examples of environmental impacts resulting from current agricultural practices include deforestation and land degradation leading to the loss of valuable ecosystems and biodiversity, accelerated climate change, over-extraction of groundwater, terrestrial acidification, and biological crises such as the outbreak of COVID-19 pandemic.
To reduce the environmental impacts of the food system, the search for more sustainable protein alternatives to replace animal-based proteins is one of the foremost research topics in food science and biotechnology today. Cellular agriculture — the production of agricultural products using cell-culturing technologies — is an approach that seeks to decouple food production from conventional agricultural farming, and, therefore, has the potential to decrease the environmental burden of food production. Cell-culturing technologies usually utilize bioreactors, creating closed production processes that allow for efficient recycling of inputs, and control of emissions from the production process. Another benefit of cell-cultured products is increased resilience of the food production system towards environmental changes, due to reduced reliance on conventional agricultural inputs. However, estimates of the environmental impacts of cell-cultured foods are still mostly lacking due to the novelty of these products.
The aim of this dissertation is to improve the understanding of environmental impacts of protein-rich cellular agricultural products in comparison with those of existing protein-rich food and feed ingredients originating from agricultural and aquacultural systems. The environmental impacts of protein-rich cellular agricultural products were quantified to gain an understanding of the production processes contributing most to these impacts, and how these differ from agricultural and aquacultural products. Lastly, the work presented in this dissertation seeks to explore how the environmental impacts of cellular agricultural protein products can be reduced through alterations to their production processes. However, as GHG emissions resulting from aquacultural production in mangrove forests have been systematically excluded from environmental impacts assessments, a fair comparison between protein produced by cellular agriculture and aquaculture is compromised. The work in this dissertation, therefore, additionally focuses on the development and application of a method to quantify the GHG emissions caused by LULUC of mangrove forest.
The protein-rich food and feed ingredients studied were microbial protein produced using hydrogen-oxidizing bacteria (HOB) (hereafter referred to as MP) and ovalbumin produced using the Trichodora reesei fungi (Tr-OVA). Shrimp was selected on the basis that aquaculture products are often underrepresented in environmental assessment studies in contrast to their importance as a protein source for many people(Gephart et al., 2021). MP and Tr-OVA are recently developed cellular agricultural products that can be used either as food or feed ingredients and are examples of cellular (MP) and acellular (Tr-OVA) products.
To address the aims of the research, the life cycle assessment (LCA) method was used. LCA allows for the quantification of inputs and outputs at all production stages throughout a product’s life cycle and the coupling of these to various environmental impact categories, such as global warming potential (GWP), land use, and eutrophication. This enables a fair comparison between different protein-rich food and feed products originating from distinctly different systems. The environmental impacts of the three protein-rich products studied were also compared to the environmental impacts of other protein-rich products found in literature.
GHG emissions caused by land use and land-use change (LULUC) of mangrove forests are often overlooked in LCA studies, despite the large contribution of LULUC emissions to climate change (approximately 13% of global emissions in the year 2015). Article I, consequently, focuses on the introduction of a method to include this specific emissions source and on applying it to a case study of shrimp farming in mangrove areas. Article II quantifies the environmental impacts of MP production. MP is a single-cell protein in the form of a flour-like powder with a 65% protein content. Because MP production uses autotrophic HOB there is no reliance on any agricultural inputs. Article III investigates the environmental impacts of Tr-OVA production. Like MO, Tr-OVA is a protein-rich powder produced in bioreactors through a closed process and has a 92% protein content. However, unlike MP, its production relies on glucose from agriculture. Using modern biotechnological tools, the gene carrying the blueprint for ovalbumin (SERPINB14) is inserted into the fungus, which then starts to produce the same protein — ovalbumin — that is normally found in chicken eggs. Cell-cultured ovalbumin can be used as a direct replacement for the chicken-based egg white that is widely used in food processing.
The results of this dissertation showed great potential for MP and Tr-OVA to reduce the environmental impacts associated with protein production — especially when replacing protein from livestock sources — with the greatest reductions seen in land use and GWP compared to other protein-rich food and feed sources. The amount of land needed to produce MP and Tr-OVA was 0.1-1.3% of the land required for beef herds. Even by comparison to peas, which generally require little land compared to other animal and plant-based protein sources, land use requirements were 73-97% less. Both MP and Tr-OVA production also led to reductions in GWP when compared to other protein-rich foods, especially by comparison to animal-based protein sources. However, agricultural protein alternatives with a lower GWP were also identified, such as peas, rapeseed cake and soybean meal.
Differences in the impacts of MP and Tr-OVA production were mostly explained by the reliance of Tr-OVA on agricultural inputs. Depending on the impact category, up to 94% of the environmental impacts of Tr-OVA production were related to its use of agriculturally sourced glucose. For MP, environmental impacts were mainly caused by the use of electricity; up to 90% depending on the category. For Tr-OVA, the impacts caused by the use of electricity were between 0% and 56%. The results for shrimp clearly indicated the importance of the inclusion of LULUC emissions from mangrove deforestation, as GHG emissions were 14-60 times higher for shrimp farming systems located in former mangrove areas than for systems that were not. The GHG emissions of shrimp produced in mangrove areas far outweighed the GWP of other protein-rich food sources and were 4.5 times higher than that of beef production from beef herds.
Despite the great potential of cellular agriculture products to reduce the environmental impacts of protein production, minor trade-offs were found. For example, the potential for ozone depletion and water scarcity were higher for Tr-OVA in comparison to other feed protein alternatives. The environmental impacts of cellular agricultural products could be further reduced by using renewable or low-carbon energy sources. However, the electricity requirements for cellular agricultural products are higher than those of agriculture and aquaculture. As many sectors are looking to move away from fossil fuels towards low-carbon electricity sources, potential greater demand for electricity from the food sector will add further pressure to increase sustainable electricity production capacity.
The work in this dissertation focused solely on the environmental impacts of food production. Additional research is needed into the role of cell-cultured food within a sustainable food system. This means that the research begun in this dissertation should be expanded to include other environmental impact categories such as biodiversity impacts, and the loss of ecosystem services. Additionally, there is a need to increase understanding of the social and economic implications of the introduction of cell-cultured foods, such as MP and Tr-OVA, into the food systems in different regions of the world.