PROBLEM SPACE

The problem of methane emissions is worth noting. It is the second largest contributor to greenhouse gas emissions after carbon dioxide. Methane is a highly effective greenhouse gas and ranks as the second-largest contributor to global warming. The main sources of methane emissions are fossil fuels, agricultural practices, and the breakdown of landfill waste, with agriculture accounting for the largest share [1]. In the last 200 years, atmospheric methane levels have more than doubled, and it is believed to contribute to 20% to 30% of climate warming since the 1750s [1].

The impact of greenhouse gases on the climate is influenced by two main characteristics: their atmospheric lifetime and their energy absorption capacity. While methane has a much shorter atmospheric lifespan of about 12 years compared to carbon dioxide's centuries, it absorbs significantly more energy during that time [2]. Additionally, methane contributes to air quality issues by leading to the formation of ground-level ozone, a harmful pollutant, and methane leaks can pose explosion risks [2]. Although estimates of methane emissions carry a degree of uncertainty, the latest assessment from the Global Methane Budget indicates that annual global methane emissions are around 580 million tons, with approximately 40% stemming from natural sources and the remaining 60% from human activities, known as anthropogenic emissions [2]. The largest anthropogenic source is agriculture, which accounts for about a quarter of total emissions, closely followed by the energy sector, which includes emissions from coal, oil, natural gas, and biofuels [2]. Methane’s short lifespan presents a critical opportunity to slow global warming. Unlike with carbon dioxide, reducing methane emissions over time can reduce the total accumulated quantity of this greenhouse gas [2,3].

A recent United Nations assessment highlights the urgent need to reduce methane emissions from agriculture as a crucial strategy in combating climate change [3]. Factors such as population growth, economic development, urban migration, and increasing demand for animal protein are driving a rise in agricultural methane emissions [3]. Methane significantly contributes to ground-level ozone formation, which is linked to approximately one million premature deaths each year [3]. It is also 80 times more potent than carbon dioxide in terms of warming over a 20-year period and has been responsible for about 30% of global warming since the pre-industrial era [3]. Methane levels are currently rising at an unprecedented rate, with notable increases observed in 2020 despite a temporary decline in carbon dioxide emissions due to the COVID-19 pandemic [2,3]. Livestock emissions, primarily from manure and digestion, account for roughly 32% of human-caused methane emissions, and with the global population nearing 10 billion, demand for animal protein is expected to rise by up to 70% by 2050 [3]. This emphasizes the crucial need for effective strategies to mitigate methane emissions.

In 2021, agriculture accounted for 31% of Canada’s total methane emissions, primarily due to enteric fermentation from beef and dairy cattle, which produces methane during the natural digestive process [4]. For instance, a lactating dairy cow emits approximately 400 grams of methane daily. These emissions accumulate rapidly- over the course of a year, the methane produced by a single dairy cow is comparable to the greenhouse gas emissions from a mid-sized vehicle driven for 20,000 kilometers [5]. To address this issue, Canada’s Greenhouse Gas Offset Credit System incentivizes farmers, municipalities, indigenous communities, foresters, and other project developers in various sectors, including agriculture, waste, and forestry, to implement domestic projects that reduce greenhouse gas emissions. The REME (Reducing Enteric Methane Emissions) protocol enhances the existing suite of protocols established since the launch of this Offset Credit System, which is part of Canada’s broader strategy to achieve a 40 to 45% reduction in domestic greenhouse gas emissions below 2005 levels by 2030, as outlined in Canada’s 2030 Emissions Reduction Plan [4,6]. This also goes hand in hand with the Global Methane Pledge, an act signed by over 150 countries, including Canada and the USA [2]. The pledge proposes to reach climate neutrality by 2050 [6]. The plan set to achieve this involves having greenhouse gas emissions reduced by 50% in 2030, with an annual 1% decrease moving forwards [6].

In the rumen, the first stomach compartment of cattle, microbes break down organic compounds from feed. This digestive process results in the release of methane as a by-product, which is belched out by ruminants in the process called enteric fermentation. Addressing this biological process is crucial to reduce methane emissions and combat global warming effectively. By leveraging this understanding of the microbiological processes involved, solutions that target methane-producing organisms directly could provide a practical and sustainable approach to reduce emissions, particularly in the context of agriculture and livestock farming. Having an effective methane emission reducing solution would be key to observe immediate effects in clearing greenhouse gas emissions, especially since it has a greater short term impact than carbon dioxide.

One of the main targeted strategies to control methane emissions is to increase the production of propionate, allowing for hydrogen to be used up instead of participating in the methanogenesis pathway [7]. This is done through making adjustments to cow diets, altering rumen fermentation. For instance, grain-based diets have shown to lower the pH of the rumen and be able to increase propionate production [7]. An alternative controlling strategy is to employ the use of bioactive compounds. Chemicals such as bromoforms, which originate from red seaweed, can directly inhibit the production of methane [7]. There are also various essential oils, tanninns, saponins, and flavonoids that possess these anti-methanogenic properties [7]. Lipid supplementation works by adding various fat sources to the cow feed in the form of oilseeds, animal fats and others to alter the fermentation pattern of the rumen and thus increase propionate production [7]. A final controlling strategy proposed is through artificial selection for lower methane producing cows [7].

Solutions that currently exist to reduce methane emissions attempt to target one of the control strategies mentioned above. Most of these solutions involve usage of feed additives. One of the mainstream and popularly used feed additives is 3-Nitrooxypropanol (3-NOP), a chemically synthesized compound which works by inhibiting the enzyme methyl coenzyme-M reductase (MCR) in methanogens, thereby reducing methane emissions by approximately 22-25% [8]. Other feed additives, such as ionophores and oils have been developed and tested but only have limited methane-reduction benefits [7]. The current solutions present several challenges. Some of these limitations include high costs for production, lack of eco-friendly manufacturing, limited/temporary efficacy, the need for continuous supplementation, environmental and health concerns. Some additives, such as bormoform and ionophore compounds, are subject to governmental restrictions in some regions, being restricted and banned for use in some countries [7,9]. More importantly, feed additives often lead to reduced feed efficiency, or raise concerns about the impact towards health and productivity of the animal (beef and dairy) [7]. For farmers whose primary concerns are to maintain their farming businesses, costly feed additives targeting methane are impractical: there is no incentive to purchase an additional costly product that simply reduces methane emissions, without significant yield or performance benefits.

As such, there remains a gap in providing a sustainable, scalable, and practical solution that can be widely adopted without imposing significant financial burdens on farmers. And for these reasons outlined, we chose to use phage derived lytic enzymes in our two step plan.

1. NASA. (2024). Methane. NASA. https://climate.nasa.gov/vital-signs/methane/?intent=121#:~:text=The%20concentration%20of%20methane%20in,(which%20began%20in%201750).
2. International Energy Agency (2022). Methane and climate change – global methane tracker 2022 – analysis. IEA. https://www.iea.org/reports/global-methane-tracker-2022/methane-and-climate-change
3. United Nations Environment Programme (2021). Methane emissions are driving climate change. here’s how to reduce them . https://www.unep.org/news-and-stories/story/methane-emissions-are-driving-climate-change-heres-how-reduce-them
4. Canada, S. (2023). Government of Canada. 2030 Emissions Reduction Plan: Clean Air, Strong Economy. https://www.canada.ca/en/services/environment/weather/climatechange/climate-plan/climate-plan-overview/emissions-reduction-2030.html
5. Agricultural Canada and Agri-Food Canada. (2019). Government of Canada. Reducing methane emissions from livestock. https://agriculture.canada.ca/en/science/story-agricultural-science/scientific-achievements-agriculture/reducing-methane-emissions-livestock
6. Global Methane Pledge. (2024). Homepage: Global methane pledge. https://www.globalmethanepledge.org/
7. Bačėninaitė, Dovilė, Karina Džermeikaitė, and Ramūnas Antanaitis. (2022). Global Warming and Dairy Cattle: How to Control and Reduce Methane Emission. Animals 12, no. 19: 2687. https://doi.org/10.3390/ani12192687
8. Yu, G., Beauchemin, K. A., & Dong, R. (2021). A Review of 3-Nitrooxypropanol for Enteric Methane Mitigation from Ruminant Livestock. Animals : an open access journal from MDPI, 11(12), 3540. https://doi.org/10.3390/ani11123540
9. Baik, M., Kim, T. H., Lee, Y., & Kim, K. H. (2022). Metabolite Profile, Ruminal Methane Reduction, and Microbiome Modulating Potential of Seeds of Pharbitis nil. Frontiers in microbiology, 13, 892605. https://doi.org/10.3389/fmicb.2022.892605