The Oligosaccharyltransferase AglB Supports Surface-Associated Growth and Iron Oxidation in Methanococcus maripaludis.

Most microbial organisms grow as surface-attached communities known as biofilms. However, the mechanisms whereby methanogenic archaea grow attached to surfaces have remained understudied. Here, we show that the oligosaccharyltransferase AglB is essential for growth of Methanococcus maripaludis strain JJ on glass or metal surfaces. AglB glycosylates several cellular structures, such as pili, archaella, and the cell surface layer (S-layer). We show that the S-layer of strain JJ, but not strain S2, is a glycoprotein, that only strain JJ was capable of growth on surfaces, and that deletion of blocked S-layer glycosylation and abolished surface-associated growth. A strain JJ mutant lacking structural components of the type IV-like pilus did not have a growth defect under any conditions tested, while a mutant lacking the preflagellin peptidase (Δ) was defective for surface growth only when formate was provided as the sole electron donor. Finally, for strains that are capable of Fe oxidation, we show that deletion of decreases the rate of anaerobic Fe oxidation, presumably due to decreased association of biomass with the Fe surface. Together, these data provide an initial characterization of surface-associated growth in a member of the methanogenic archaea. Methanogenic archaea are responsible for producing the majority of methane on Earth and catalyze the terminal reactions in the degradation of organic matter in anoxic environments. Methanogens often grow as biofilms associated with surfaces or partner organisms; however, the molecular details of surface-associated growth remain uncharacterized. We have found evidence that glycosylation of the cell surface layer is essential for growth of on surfaces and can enhance rates of anaerobic iron corrosion. These results provide insight into the physiology of surface-associated methanogenic organisms and highlight the importance of surface association for anaerobic iron corrosion.