Recently, Scientists at Agharkar Research Institute (ARI), Pune have isolated 45 different strains of methanotrophic bacteria which are found to be capable of reducing methane emissions from rice plants.

More about the news:

  • The work is published in Antonie van Leeuwenhoek, an International Journal of General and Molecular Microbiology.
  • Scientists along with isolating strains of methanotrophic bacteria also created the first indigenous methanotroph culture.
  • Some of the strains were used as bio-inoculants.
  • Key finding: 
    • A decrease in methane emissions in inoculated plants with a positive or neutral effect on the growth of the rice. 
    • This can help in development of microbial inoculants for methane mitigation in rice.
  • Benefit: 
    • Reduce global warming: The isolated strains may help in understanding the effect of various factors on methane mitigation.
    • Methane value addition (valorization): Bio-methane generated from waste can be used by the methanotrophs and can be converted to value-added products such as single-cell proteins, carotenoids, biodiesel.

Why rice fields?

  • Waterlogged wetlands: Rice fields are waterlogged for a considerable period and are human-made wetlands.
  • Generation of methane in the rice field: Anaerobic degradation of organic matter results in the generation of methane. 
  • Rice fields are one of the largest methane emissions source.Rice fields contribute to nearly 10% of global methane emissions.


  • Methanotrophs are a key group of environmental microorganisms that play an integral role in the global cycling of methane. 
  • They help in oxidation of methane in the natural environment. 
  • They oxidize methane produced geothermally and by the anaerobic metabolism of methanogenic bacteria, thereby reducing the release of methane to the atmosphere from landfill sites, wetlands, and rice paddies.  



Bio-inoculants are living organisms containing strains of specific bacteria, fungi, or algae which:


  • Take nitrogen from the air and make it available to plants- reducing the need for nitrogen fertilizer.
  • Make inorganic phosphate and micronutrients soluble and available to plants.
  • Collect and store available nutrients.
  • Enhance plant uptake of phosphorus and zinc.
  • Provide physical barriers against pathogens.
  • Stimulate plant growth.
  • Decompose organic residues.


  • Methane is the second most abundant greenhouse gas after carbon dioxide (CO2), which accounts for 14% of global greenhouse gas emissions.
  • Global warming potential of methane: The 20-year global warming potential of methane is 84.
    • It traps 84 times more heat per mass unit than carbon dioxide (CO2).
  • A significant source of human-made methane emissions is fossil fuel production.
  • Other source: livestock, wetlands and landfills.

Initiatives to reduce Methane pollution

  • Climate and Clean Air Coalition To Reduce Short-Lived Climate Pollutants (CCAC), a global partnership of cities, international organizations, NGOs and the private sector that is seeking to rapidly reduce SLCPs(Short Lived climate Pollutants) like methane and black carbon by improving waste management practices.
  • The C40 Cities Climate Leadership Group and its partner the Clinton Climate Initiative Cities programme are also working with the Coalition to assist urban areas in cutting methane emissions from across the waste chain, including from landfills and pollution linked with organic waste like food.
    • C40 is a network of the world’s megacities committed to addressing climate change.
    • C40 supports cities to collaborate effectively, share knowledge and drive meaningful, measurable and sustainable action on climate change.
  • The 1999 Gothenburg Protocol to Abate Acidification, Eutrophication and Ground-level Ozone : The Protocol sets national emission ceilings for 2010 and now upto 2020, for four pollutants: sulphur (SO2), nitrogen oxides (NOx), volatile organic compounds (VOCs) and ammonia (NH3).  
    • Parties have to report on their emissions once a year. 
    • In addition, the Protocol requires Parties to provide projections of their future emissions.