Discovery illuminates how
bacteria turn methane gas into liquid methanol
May 9, 2019
Northwestern University
Researchers have found that
the enzyme responsible for the methane-methanol conversion in methanotrophic
bacteria catalyzes the reaction at a site that contains just one copper ion.
This finding could lead to newly designed, human-made catalysts that can convert
methane -- a highly potent greenhouse gas -- to readily usable methanol with
the same effortless mechanism.
Known for their ability to
remove methane from the environment and convert it into a usable fuel,
methanotrophic bacteria have long fascinated researchers. But how, exactly,
these bacteria naturally perform such a complex reaction has been a mystery.
Now an interdisciplinary team
at Northwestern University has found that the enzyme responsible for the
methane-methanol conversion catalyzes this reaction at a site that contains
just one copper ion.
This finding could lead to
newly designed, human-made catalysts that can convert methane -- a highly
potent greenhouse gas -- to readily usable methanol with the same effortless
mechanism.
"The identity and
structure of the metal ions responsible for catalysis have remained elusive for
decades," said Northwestern's Amy C. Rosenzweig, co-senior author of the
study. "Our study provides a major leap forward in understanding how
bacteria methane-to-methanol conversion."
"By identifying the type
of copper center involved, we have laid the foundation for determining how
nature carries out one of its most challenging reactions," said Brian M.
Hoffman, co-senior author.
The study will publish on Friday,
May 10 in the journal Science. Rosenzweig is the Weinberg Family
Distinguished Professor of Life Sciences in Northwestern's Weinberg College of
Arts and Sciences. Hoffman is the Charles E. and Emma H. Morrison Professor of
Chemistry at Weinberg.
By oxidizing methane and
converting it to methanol, methanotrophic bacteria (or
"methanotrophs") can pack a one-two punch. Not only are they removing
a harmful greenhouse gas from the environment, they are also generating a
readily usable, sustainable fuel for automobiles, electricity and more.
Current industrial processes
to catalyze a methane-to-methanol reaction require tremendous pressure and
extreme temperatures, reaching higher than 1,300 degrees Celsius.
Methanotrophs, however, perform the reaction at room temperature and "for
free."
"While copper sites are
known to catalyze methane-to-methanol conversion in human-made materials,
methane-to-methanol catalysis at a monocopper site under ambient conditions is
unprecedented," said Matthew O. Ross, a graduate student co-advised by
Rosenzweig and Hoffman and the paper's first author. "If we can develop a
complete understanding of how they perform this conversion at such mild
conditions, we can optimize our own catalysts."
The study, "Particulate
methane monooxygenase contains only mononuclear copper centers," was
supported by the National Institutes of Health (award numbers GM118035,
GM111097 and 5T32GM008382) and the National Science Foundation (award number
1534743).
Story Source:
Materials provided by Northwestern University.
Original written by Amanda Morris. Note: Content may be edited for style
and length.
Journal Reference:
Matthew O. Ross, Fraser
MacMillan, Jingzhou Wang, Alex Nisthal, Thomas J. Lawton, Barry D. Olafson,
Stephen L. Mayo, Amy C. Rosenzweig, Brian M. Hoffman. Particulate methane
monooxygenase contains only mononuclear copper centers. Science, 2019; 364
(6440): 566-570 DOI: 10.1126/science.aav2572
No comments:
Post a Comment