Simultaneous Oxidation of Atmospheric Methane, Carbon Monoxide and Hydrogen for Bacterial Growth

• Published in: Microorganisms
• Main Authors: Tveit, Alexander Tøsdal, Schmider, Tilman, Hestnes, Anne Grethe, Lindgren, Matteus, Didriksen, Alena, Svenning, Mette Marianne
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI 2021
• Subjects: VDP::Mathematics and natural science: 400::Zoology and botany: 480; VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480; Arctic
• Online Access: https://hdl.handle.net/10037/20296; https://doi.org/10.3390/microorganisms9010153

The second largest sink for atmospheric methane (CH 4 ) is atmospheric methane oxidizing-bacteria (atmMOB). How atmMOB are able to sustain life on the low CH 4 concentrations in air is unknown. Here, we show that during growth, with air as its only source for energy and carbon, the recently isolated atmospheric methane-oxidizer Methylocapsa gorgona MG08 (USCα) oxidizes three atmospheric energy sources: CH 4 , carbon monoxide (CO), and hydrogen (H 2 ) to support growth. The cell-specific CH 4 oxidation rate of M. gorgona MG08 was estimated at ~0.7 × 10 −18 mol cell −1 h −1 , which, together with the oxidation of CO and H 2 , supplies 0.38 kJ Cmol −1 h −1 during growth in air. This is seven times lower than previously assumed necessary to support bacterial maintenance. We conclude that atmospheric methane-oxidation is supported by a metabolic flexibility that enables the simultaneous harvest of CH 4 , H 2 and CO from air, but the key characteristic of atmospheric CH 4 oxidizing bacteria might be very low energy requirements.