Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mystery of archaeal butane degradation solved

18.10.2016

Researchers from the Max Planck Institute for Marine Microbiology in Bremen and their colleagues from the Helmholtz-Zentrum für Umweltforschung (UFZ) in Leipzig discovered microbial communities thriving on the hydrocarbon butane without the help of molecular oxygen. The microbial consortia, obtained from hydrothermally heated sediments in Guaymas Basin, Gulf of California, use unprecedented biochemistry to feed on butane.

Gaseous hydrocarbons in the seafloor


Cell specific visualization of the butane oxidizing consortia. In red the archaea Candidatus Syntrophoarcheum butanivorans, in green the bacteria Hotseep-1

Rafael Laso-Pérez. Max Planck Institute for Marine Microbiology and Victoria Orphan, Caltech, USA


Scheme of the butane oxidation in the archaea (Candidatus Syntrophoarcheum butanivorans) and the coupled sulfate reduction in the partner bacteria Hotseep-1. Butane binds to coenzyme M in the acti

Max Planck Institute for Marine Microbiology

Natural gas is often released at the seafloor surface. In the upper sediment layers methane is formed by methanogenic archaea (see box). Economically more valuable gas reservoirs are however situated in deeper layers of the seafloor.

Here gas forms in purely chemical reactions from geothermally heated biomass of plant, animal and microbial origin. Along with methane, the thermogenic (thermally generated) gas contains other hydrocarbons such as propane and butane.

As anyone who has lit a gas stove, a lighter or started a gas powered car knows, burning gas requires oxygen. Also many microorganisms eat hydrocarbon gases by using oxygen, for instance in well-oxygenated top sediment layers. When the oxygen is used up, other microorganisms take over, however most of their metabolic solutions to activate and fully oxidize their substrate are completely unknown.

How microorganisms consume natural gas without molecular oxygen

Distinct microorganisms specialized on the anaerobic oxidation of different hydrocarbons. Even though methane is the simplest hydrocarbon, its anaerobic oxidation (AOM) coupled to sulfate reduction involves a team of two specific partners, archaeal and bacterial. The methane-oxidizing archaea (ANME) use similar enzymes as their methane-producing (methanogenic) relatives, however in reverse direction.

To activate the methane molecule these archaea produce large quantities of the enzyme Methyl-Coenzyme M Reductase (MCR). MCR binds the methane as methyl group to the sulfur compound coenzyme M, thereby starting the oxidation process which eventually leads to carbon dioxide (CO2).

The ANME however do not possess enzymes for sulfate reduction: this part of the AOM process is covered by the sulfate-reducing partner. On the other hand, the anaerobic oxidation of the larger gases, propane and butane, was found in bacteria that couple hydrocarbon oxidation to sulfate reduction in one cell.

The novel pathway for butane is based on the degradation of the anaerobic methane oxidation
In their latest research published in Nature microbiologists from Bremen, Leipzig, Göttingen and Bielefeld describes a new type of microbial consortia thriving on a butane diet. Similar to AOM these consortia also consist of archaeal and bacterial species. Surprisingly, the genomes of both partner organisms lack the typical genes for anaerobic butane activation.

“Instead we found genes distantly related to the MCR of methanogenic and methanotrophic archaea. Do the encoded enzymes have a role in butane oxidation?” thought PhD student Rafael Laso-Pérez, first author of the research article “And if that proves to be true, what other reactions would lead to a complete oxidation of butane to carbon dioxide?” Only painstaking lab work, and many different analyses, could solve this puzzle.

To validate this theory the microbiologist Dr. Florin Musat and his colleagues from the ProVIS at the UFZ in Leipzig used ultra-high resolution mass spectroscopy to look at intracellular metabolites. His team succeeded in identifying the forecasted intermediate - butyl-coenzyme M. “Up to date, methyl-coenzyme M reductases where known to be highly specific to the methane metabolism.

By proving the formation of butyl-coenzyme M in these archaea we demonstrate that this enzyme family can indeed handle larger hydrocarbons”, explains Dr. Musat. The research teams completed the pathway by finding other genes of the methanogenesis pathway and key elements of the butyrate and acetate metabolism.

“Combining these pathways in the right manner allows complete oxidation of butane in archaea. Evolution is ingenious: Some old tricks from other species were copied and adapted. This is known as horizontal gene transfer, this means that DNA sequences are taken from other species” explains Dr. Gunter Wegener, initiator of this study. “It was quite a long way to solve this puzzle and involved investigators from many different fields.”

Like their methane-consuming relatives the butane-oxidizing archaea are not able to fulfill the job on their own. As in AOM consortia the butane oxidizers have partner bacteria. “Electron microscopy shows tiny protein compounds connecting bacterial and archaeal cells. Electrons travel on these nanowires from the archaea to the bacteria that use them to reduce sulfate. We were able to show syntrophic electron exchange via protein nanowires for a second example,” says Dr. Gunter Wegener and adds:” Studying the archaea is like a journey in the past, and the coenzyme M reactions are among the earliest in the history of life”. All discovered species need a name – and so their new lab pet was baptized Candidatus Syntrophoarchaeum butanivorans – a butane-eating archaeon that needs a little help (syntrophy) by a partner for life.

Open questions remain

Where else on the planet do these archaea exist? Why and how did evolution lead to team work of microorganisms in consortia vs. microorganisms able to catalyze both oxidation and reduction reactions? Are there other variants of methyl-coenzyme M reductases able to activate even higher alkanes than butane? Such questions will keep researchers busy at the Max Planck Institute for Marine Microbiology and the Helmholtz Zentrum für Umweltforschung (UFZ).

Please direct your questions to
Rafael Laso-Perez, Max Planck Institute for Marine Microbiology,
D-28359 Bremen, Phone: 0421 2028 867, rlperez@mpi-bremen.de
Dr. Gunter Wegener, Max Planck Institute for Marine Microbiology,
D-28359 Bremen, Phone: 0421 2028 867, gwegener@mpi-bremen.de
Dr. Florin Musat, Helmholtz-Zentrum für Umweltforschung (UFZ) Leipzig,
D-04318 Leipzig, Phone: 0341 235 1005, florin.musat@ufz.de
Or the press office
Dr. Manfred Schloesser and Dr. Fanni Aspetsberger
presse@mpi-bremen.de Phone: 0421 2028 704

Original publication
Thermophilic archaea activate butane via alkyl-CoM formation. Rafael Laso-Pérez, Gunter Wegener, Katrin Knittel, Friedrich Widdel, Katie J. Harding , Viola Krukenberg, Dimitri V. Meier, Michael Richter, Halina E. Tegetmeyer, Dietmar Riedel, Hans-Hermann Richnow, Lorenz Adrian, Thorsten Reemtsma, Oliver Lechtenfeld, Florin Musat. Nature, 2016 doi: 10.1038/nature20152

Participating Institutions
Max Planck Institute for Marine Microbiology, Bremen
MARUM, Zentrum für Marine Umweltwissenschaften, Universität Bremen
Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany.
Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven
Centrum für Biotechnologie, Universität Bielefeld
Helmholtz Centre for Environmental Research – UFZ, Leipzig

Weitere Informationen:

http://www.mpi-bremen.de Web site of the Max Planck Institute for Marine Microbiology

Dr. Manfred Schloesser | Max-Planck-Institut für marine Mikrobiologie

More articles from Earth Sciences:

nachricht Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>