Illustration (IMAGE) Max-Planck-Gesellschaft Caption The massive complex carries out flavin-based electron bifurcation (FBEB) and directly transfers electrons to the CO2-reducing site for entry into the methanogenic cycle. Hdr = Heterodisufide reductase, Fdh = Format dehydrohenase, Fmd= formylmethanofuran dehydrogenase. Reprinted with permission from Watanabe & Pfeil-Gardiner et al., Science (2021) Credit Max Planck Institute of Biophysics/Pfeil-Gardiner Usage Restrictions Use of images is limited to editorial coverage of scientific topics relating to the activities of the Max Planck Society. Any kind of commercial use (including, in particular, the exploitation of images by means of sale or incorporation in image databases or image catalogues) as well as any promotional use/use for merchandise purposes, disclosure to third parties or granting of related rights to third parties is expressly not permitted. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.