A recent scientific study published in Cell has unveiled the critical role of hydrogen in the survival of archaea, single-celled organisms considered microbial ancestors to humans from two billion years ago. The research led by Monash University scientists reveals how archaea use hydrogen gas to generate energy, allowing them to thrive in extreme environments. By analyzing thousands of archaea genomes, the team identified unique hydrogen-producing enzymes, including [FeFe]-hydrogenases, previously thought to be exclusive to eukaryotes and bacteria. These enzymes, found in diverse environments like hot springs and oil reservoirs, offer potential for efficient biological hydrogen production. The study's findings not only redefine our understanding of archaea biology but also present opportunities for leveraging their ancient hydrogen-based energy strategies for modern biotechnological applications and transitioning towards a sustainable green economy. Professor Chris Greening highlights the efficiency and resilience of biological catalysts in hydrogen utilization, paving the way for improved industrial hydrogen processes. Overall, the research showcases the enduring legacy of archaea's hydrogen metabolism and its potential impact on future energy solutions.