Activated biochar feed additive shows promise for cutting livestock methane emissions
image: Developing an activated biochar-mineral supplement for reducing methane formation in anaerobic fermentation
Credit: Sara Tahery, Mariano C. Parra, Paul Munroe, David R. G. Mitchell, Sarah J. Meale & Stephen Joseph
A newly engineered biochar-based feed supplement could help reduce methane emissions from livestock while maintaining healthy digestion, offering a promising tool for more climate-friendly agriculture.
In a new study, researchers developed an activated biochar-mineral supplement designed specifically for use in ruminant animals such as cattle. The material combines wheat straw biochar with minerals and undergoes chemical activation to enhance its surface chemistry and reactivity.
“Our goal was to design a multifunctional supplement that not only reduces methane emissions but also supports stable rumen fermentation,” said the study’s lead author. “The results suggest we can achieve both.”
Methane is a potent greenhouse gas, and livestock production is a major global source due to enteric fermentation in the rumen. While biochar has been widely studied in soils, its application as a feed additive has received less attention.
To address this gap, the research team engineered a biochar-mineral composite rich in oxygen-containing functional groups and reactive sites. Laboratory analyses showed the material has a high surface area and a high concentration of free radicals, which are known to promote redox reactions and methane oxidation.
The supplement was tested using an in vitro rumen fermentation system with fluid collected from cattle. When added at moderate levels, the material significantly reduced methane production without disrupting digestion.
After 48 hours, methane emissions dropped by about 19 percent at a 4 percent inclusion rate and by nearly 30 percent at a 6 percent inclusion rate. Total gas production also decreased, indicating reduced fermentation-related emissions, while key fermentation indicators such as volatile fatty acids remained stable.
“These reductions are substantial, especially considering that the supplement did not negatively affect fermentation performance,” the authors noted.
The researchers attribute the methane reduction to several interacting mechanisms. The biochar structure provides a habitat for microbial communities and facilitates electron transfer processes. Oxygen-containing functional groups and free radicals on the surface may catalyze methane oxidation. In addition, nitrate and iron components in the supplement can compete with methanogens for electrons, suppressing methane formation.
Microscopic imaging revealed that the supplement forms complex organo-mineral structures that interact closely with rumen microorganisms. These interactions likely play a role in modifying microbial activity and reducing methane production.
Beyond methane mitigation, the supplement also influenced nutrient dynamics in the rumen. At higher inclusion rates, it reduced the release of certain dissolved minerals such as phosphorus and magnesium, suggesting potential benefits for nutrient efficiency.
Importantly, the study found no adverse effects on overall digestion. The supplement maintained stable pH conditions and did not significantly alter total volatile fatty acid production, both of which are critical indicators of rumen health.
While the findings are based on laboratory simulations, the researchers emphasize their relevance for real-world applications.
“This study provides a strong foundation for future in vivo trials and the development of practical feed additives for methane mitigation,” the authors said.
If validated in live animals, the technology could offer a scalable strategy to reduce emissions from the livestock sector, contributing to global efforts to combat climate change while supporting sustainable agricultural production.
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Journal Reference: Tahery, S., Parra, M.C., Munroe, P. et al. Developing an activated biochar-mineral supplement for reducing methane formation in anaerobic fermentation. Biochar 7, 26 (2025).
https://doi.org/10.1007/s42773-024-00403-5
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About Biochar
Biochar (e-ISSN: 2524-7867) is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field.