Methane is a potent greenhouse gas and 2nd most prominent contributor to global warming and climate change after CO2. On a 100-year timescale, methane has 28 times greater global warming potential than CO2 and is 84 times more potent on a 20-year timescale. Reducing methane emissions is a critical component of efforts to combat climate change. It is seen as a crucial short-term strategy because of its high global warming potential, and understanding and managing methane emissions is essential for mitigating the impact of climate change.
Critical sources of methane emissions are
1. Natural Sources:
Natural Gas Seeps, and
2. Human Activities:
Energy Production (leakage and flaring during production, transportation, and use of fossil fuels),
Agriculture (from enteric fermentation in the stomachs of ruminant animals, manure management, and rice cultivation in flooded fields),
Landfills (anaerobic decomposition of organic waste),
Wastewater treatment (organic matter digested in anaerobic conditions),
Biomass burning (incomplete combustion of biomass, such as forests, crop residues, and peatlands),
Hydraulic fracturing (leaks from wells and pipelines)
Efforts to mitigate methane emissions include improving waste management, reducing methane leaks from energy infrastructure, implementing more efficient livestock and agricultural practices, and promoting the capture and utilization of methane from sources like landfills and wastewater treatment plants.
Methanotrophic bacteria, also known as methanotrophs, are a specialized group of microorganisms that can oxidize methane as their primary carbon and energy source. Methanotrophs play a significant role in the global carbon cycle by converting methane into carbon dioxide (CO2), a less potent greenhouse gas. Methanotrophs consume over 80 % of the endogenous high concentrations of methane produced in anaerobic compartments before they escape into the atmosphere. Some methanotrophs can also fix carbon dioxide (CO2) into biomass, using energy obtained from methane oxidation. Methane oxidation is an essential ecological function and contributes to ecosystem carbon cycling.
Source: Methane metabolism in aerobic methanotrophs (Zhu et al., 2017)
Methanotrophic bacteria inhabit a wide range of environments where methane emissions occur. The metabolic capability of methanotrophic bacteria to convert methane to carbon dioxide has practical applications.
Bioremediation: clean up environments contaminated with methane or other hydrocarbons.
Wastewater Treatment: remove methane and other volatile organic compounds from wastewater.
Biogas Production: Enhance methane yield in anaerobic digestion processes used for biogas production.
Methanol Production: One can harness methanotrophs for the biological conversion of methane to methanol, which offers various industrial applications.
Overall, Methanotrophic bacteria are fascinating microorganisms with significant ecological and industrial relevance due to their unique metabolic abilities and role in mitigating methane emissions.
Dr. Tejaswini M E
EMPRI Fellow - Climate Change
Department for Climate Change
Environmental Management & Policy Research Institute (EMPRI)