Lessons on living with lanthanides

Abstract

Ten years ago, in a steaming volcanic mud pot in Italy, microbiologists discovered a bizarre bacterium—the first known organism that couldn’t live without lanthanides. To help it feed on methane, Methylacidiphilum fumariolicum relies on a methanol dehydrogenase (MDH) enzyme that has a rare-earth element such as cerium or lanthanum at its heart. Now, Eric J. Schelter of the University of Pennsylvania has made a complex that mimics the enzyme’s active site, shedding light on the lanthanide’s crucial role in the microbe’s metabolism (J. Am. Chem. Soc. 2017, DOI: 10.1021/jacs.7b12318). Lanthanide ions have very poor bioavailability because they tend to precipitate out of neutral water. But in the hot, acidic conditions of the Solfatara volcanic crater on the outskirts of Naples, hardy microbes have access to a rare-earth smorgasbord at concentrations of 2–3 µM. Indeed, M. fumariolicum depends on a supply of lanthanides to thrive (Environ. Microbiol. 2013, DOI: 10.1111/1462-2920.12249). “I