Viable methanotrophic bacteria enriched from air and rain can oxidize methane at cloud-like conditions

Šantl Temkiv, Tina (author), Finster, Kai (author), Hansen, Bjarne Munk (author), Pašić, Lejla (author), Karlson, Ulrich Gosewinkel (author)

Atmospheric methane is degraded by both photooxidation and, in topsoils, by methanotrophic bacteria, but this may not totally account for the global sink of this greenhouse gas. Topsoils are a prominent source of airborne bacteria, which can degrade some organic atmospheric compounds at rates similar to photooxidation. Although airborne methanotrophs would have direct access to atmospheric methane, their presence and activity in the atmosphere has not been investigated so far. We enriched airborne met- hanotrophs from air and rainwater and showed that they oxidized methane at atmospheric concentration. The majority of seven OTUs, detected using pmo A gene clone libraries, were affiliated to the type II methanotrophic genera Methylocystis and Methylosi- nus . Furthermore, 16S rRNA gene clone libraries revealed the presence of OTUsaffiliated with the genera Hyphomicrobium and Variovorax , members of which can stimulate methane oxidation by yet uniden- tified mechanisms. Simulating cloud-like conditions revealed that although both low pH and the presence of common cloud-borne organics negatively affected methane oxidation,airborne methanotrophs were able to degrade atmospheric methane in most cases. We demonstrate here for the first time that viable methanotrophic bacteria are present in air and rain and thus expand our knowledge on the global distri- bution of methanotrophs to include the atmosphere. The fact that they can degrade methane to below atmospheric concentrations when inoculated into artificial cloud water leads to an important possible effect of these organisms: the atmosphere may not only function as a medium for microbial dissemina- tion, but also as a site of active microbial methane turnover.

• Language: English
• Keywords: air microbiology, methane, methanotrophs, aerial dispersal, airborne bacteria
• Work type: Not categorized
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Year: 2013
• Number of pages: Str. 373-384
• Numbering: Vol. 29, issue 3
• PID: 20.500.12556/RUL-37684
• UDC: 577.2
• ISSN on article: 0393-5965
• DOI: 10.1007/s10453-013-9287-1
• COBISS.SI-ID: 2744143
• Publication date in RUL: 10.07.2015

Record is a part of a journal

• Title: Aerobiologia
• Shortened title: Aerobiologia
• Publisher: Pitagora Editrice
• ISSN: 0393-5965
• COBISS.SI-ID: 1432596

Secondary language

• Language: English
• Keywords: Methylocystis