Comparison of carbon footprint and water scarcity footprint of milk protein produced by cellular agriculture and the dairy industry.

Rightly or wrongly, the general perception is that both animal- and plant-sourced protein-rich foods are associated with significant environmental impacts. Producers and supply chains are experiencing increased pressures as a result of the mounting environmental concerns related to greenhouse gas (GHG) emissions and the use of local water and land resources, and health and ethical concerns over the raising and treatment of animals in food production. To meet future nutrition requirements and the growing demand for protein, alternative more efficient ways of protein production may be needed to complement existing plant- and animal-sourced production systems, which must also improve overall efficiency. In support of these arguments, the purpose of the study by the authors cited was therefore to examine the role relative to dairy of microbially produced milk proteins in meeting future demand for more sustainably produced protein of high nutritional quality. Their paper reports the carbon footprint and water scarcity footprint (WSF) of a milk protein, beta-lactoglobulin, produced by cellular agriculture and comparing this to extracted dairy protein from milk. The calculations of the microbially produced proteins were based on a model of a hypothetical industrial-scale facility.

The process followed evaluated beta-lactoglobulin production in bioreactor cultivation with the filamentous fungus Trichoderma reesei and the downstream processing thereof for product purification. The model considered four production scenarios in four different locations (New Zealand, Germany, US, and Australia) in a cradle-to-gate system. The scenarios considered different sources of carbon (glucose and sucrose), different options for the fungal biomass treatment (waste or animal feed) and for the purification of the product. The carbon footprint and WSF modelling was compared to calculations and actual data on extracted dairy protein production.

The results showed that the carbon footprint of microbially produced protein varied depending on the location (energy profile) and source of carbon used. The lowest carbon footprint (5.5 ton CO₂e per ton protein) was found with sucrose-based production in NZ and the highest (17.6 ton CO₂e per ton protein) in Australia with the glucose and chromatography step. The WSF results varied between 88 and 5030 m³ world equivalent per ton of protein, depending on the location, type of sugar and purification method used. The feed production had a bigger impact on the WSF than on the carbon footprint. Both footprints were sensitive to the process parameters of final titre and protein yield from sugar. The results for milk protein were not of dissimilar magnitude, about 10 ton CO₂e C per ton of protein and 290–11,300 m³ world equivalent per ton of protein.

It was concluded that the environmental impacts of microbially produced milk protein were of the same magnitude as for extracted dairy protein. The main contributions were sugar and electricity production. The carbon footprints of proteins produced by cellular agriculture have potential for significant reduction when renewable energy and more sustainable carbon sources are used and combined with evolving knowledge and technology in microbial production. Similarly, the carbon footprint of milk proteins can potentially be reduced through methane reduction technologies and I may add, also renewable energy, and the application of regenerative agricultural practices.