title: Microbial life under extreme energy limitation.
abstract: A great number of the bacteria and archaea on Earth are found in subsurface environments in a physiological state that is poorly represented or explained by laboratory cultures. Microbial cells in these very stable and oligotrophic settings catabolize 10⁴- to 10⁶-fold more slowly than model organisms in nutrient-rich cultures, turn over biomass on timescales of centuries to millennia rather than hours to days, and subsist with energy fluxes that are 1,000-fold lower than the typical culture-based estimates of maintenance requirements. To reconcile this disparate state of being with our knowledge of microbial physiology will require a revised understanding of microbial energy requirements, including identifying the factors that comprise true basal maintenance and the adaptations that might serve to minimize these factors.
authors: NASA Ames Research Center, Mail Stop 239-4, Moffett Field, California 94035-1000, USA. tori.m.hoehler@nasa.gov
authors: Tori M
authors: TM
authors: Hoehler
authors: Bo Barker
authors: BB
authors: Jørgensen
mesh_terms: D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D001431:Bacteriological Techniques; D004734:Energy Metabolism / Q000502:physiology*; D004783:Environmental Microbiology