A team from Northwestern Polytechnical University (NWPU), led by Professor Qiu Qiang, has made a groundbreaking discovery in regulating methane emissions from ruminants. Collaborating with the Chinese Academy of Sciences and Nanjing Agricultural University, their findings were published in Science. The study, "Rumen ciliates modulate methane emissions in ruminants," reveals how rumen ciliates affect methane production.

Methane, a potent greenhouse gas, has a warming potential 23 times that of carbon dioxide. Ruminants like cattle and sheep produce significant methane during digestion, contributing over 30% of global anthropogenic emissions. While ciliates, comprising 25-50% of rumen microbes, have been linked to methane production, their role was previously unclear.

The team used the "Protist 10,000 Genomes Project (P10K)" to overcome challenges in microbial composition and genomic data contamination. They developed genome decontamination techniques, creating a high-quality catalog of 450 rumen ciliate genomes, 87% newly identified. This catalog categorizes ciliates into Vestibuliferida and Entodiniomorphida, providing a foundation for further study.

The key breakthrough was discovering a novel hydrogen-producing organelle, the "hydrogenosome." Unlike known double-membrane hydrogenosomes, this single-membrane structure originates from the endomembrane system. It houses [FeFe]-hydrogenase and flavin-based enzymes, facilitating hydrogen production and oxygen scavenging, crucial for methanogens and maintaining anaerobic conditions.

The team correlated ciliate abundance with methanogen levels and methane emissions through global metagenomic data and field measurements. Hydrogenosomes are more abundant in ciliate-rich regions, significantly enhancing methane production, a finding validated through co-culture experiments.

This research offers insights for developing targeted methane reduction technologies, potentially inhibiting ciliates or hydrogenosome function, paving the way for sustainable livestock farming. Led by Professor Wang Wen, NWPU's team continues to achieve significant results in life sciences, contributing to scientific progress and sustainable development.