Microbial Stabilization and Kinetic Enhancement of Marine Methane Hydrates

Abstract

In clathrate hydrates, a water host lattice encages small guest molecules in cavities. Methane hydrates are the most widespread in-situ clathrate in the permafrost and continental-shelf ocean regions, constituting a significant energy resource, and prompting recent marine-hydrate gas-production trials. Despite exciting engineering advances and a few marine-mimicking laboratory studies of methane-hydrate kinetics and stabilization, from microbial perspectives, little is known about a potential microbial origin of marine hydrates, nor their possible formation kinetics or potential stabilization by microbial sources. Here, for the first time, we show that an exported, extra-cytoplasmic porin – produced by a marine methylotrophic bacterium culture – provides the basis for kinetic enhancement and stabilization of methane hydrates under conditions simulating the seabed environment. We then identify the key protein at play, and we therefore suggest microbe-based stabilization of marine hydrates is evidently a property likely to be found in many marine bacteria. Our research opens the possibility of managing marine-hydrate deposits using microbiological strategies for environmental and societal benefit.

Keywords:

• Methane hydrates
• methylotrophy

Acknowledgements

NE thanks John Osegovic for interesting and helpful conversations.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

NE, PKN and MRG thank Science Foundation Ireland for funding under grant [SFI 15/ERC-I3142]. MRG also thanks the Irish Research Council for a Government-of-Ireland postdoctoral fellowship [GOIPD/2016/365]. CCRA and TK were supported by a QUB AFQCC grant funded by Invest Northern Ireland. SD was supported by a Commonwealth PhD Scholarship. JY was supported by a DENI studentship. Mass spectrometry analysis was supported by the Wellcome Trust [grant number 094476/Z/10/Z] which funded the purchase of the TripleTOF 5600 mass spectrometer at the BSRC Mass Spectrometry and Proteomics Facility, University of St Andrews.