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Fungal Enzymes Team Up to More Efficiently Break Down Cellulose

Cost-effectively breaking down bioenergy crops into sugars that can then be converted into fuel is a barrier to commercially producing sustainable biofuels. Enabled by DOE User Facilities, a team reports that early lineages of fungi can form enzyme complexes capable of degrading plant biomass.

Argonne Scientists Make Vanadium Into a Useful Catalyst for Hydrogenation

In a new study, Argonne chemist Max Delferro boosted and analyzed the unprecedented catalytic activity of an element called vanadium for hydrogenation - a reaction that is used for making everything from vegetable oils to petrochemical products to vitamins.

Printed, Flexible and Rechargeable Battery Can Power Wearable Sensors

Nanoengineers at the University of California San Diego have developed the first printed battery that is flexible, stretchable and rechargeable. The zinc batteries could be used to power everything from wearable sensors to solar cells and other kinds of electronics. The work appears in the April 19, 2017 issue of Advanced Energy Materials.

Neutrons Provide the First Nanoscale Look at a Living Cell Membrane

A research team from the Department of Energy's Oak Ridge National Laboratory has performed the first-ever direct nanoscale examination of a living cell membrane. In doing so, it also resolved a long-standing debate by identifying tiny groupings of lipid molecules that are likely key to the cell's functioning.

How X-Rays Helped to Solve Mystery of Floating Rocks

Experiments at Berkeley Lab's Advanced Light Source have helped scientists to solve a mystery of why some rocks can float for years in the ocean, traveling thousands of miles before sinking.

Special X-Ray Technique Allows Scientists to See 3-D Deformations

In a new study published last Friday in Science, researchers at Argonne used an X-ray scattering technique called Bragg coherent diffraction imaging to reconstruct in 3-D the size and shape of grain defects. These defects create imperfections in the lattice of atoms inside a grain that can give rise to interesting material properties and effects.

Neptune: Neutralizer-Free Plasma Propulsion

The most established plasma propulsion concepts are gridded-ion thrusters that accelerate and emit a larger number of positively charged particles than those that are negatively charged. To enable the spacecraft to remain charge-neutral, a "neutralizer" is used to inject electrons to exactly balance the positive ion charge in the exhaust beam. However, the neutralizer requires additional power from the spacecraft and increases the size and weight of the propulsion system. Researchers are investigating how the radio-frequency self-bias effect can be used to remove the neutralizer altogether, and they report their work in this week's Physics of Plasmas.

Report Sheds New Insights on the Spin Dynamics of a Material Candidate for Low-Power Devices

In a report published in Nano LettersArgonne researchers reveal new insights into the properties of a magnetic insulator that is a candidate for low-power device applications; their insights form early stepping-stones towards developing high-speed, low-power electronics that use electron spin rather than charge to carry information.

Researchers Find Computer Code That Volkswagen Used to Cheat Emissions Tests

An international team of researchers has uncovered the mechanism that allowed Volkswagen to circumvent U.S. and European emission tests over at least six years before the Environmental Protection Agency put the company on notice in 2015 for violating the Clean Air Act. During a year-long investigation, researchers found code that allowed a car's onboard computer to determine that the vehicle was undergoing an emissions test.

Physicists Discover That Lithium Oxide on Tokamak Walls Can Improve Plasma Performance

A team of physicists has found that a coating of lithium oxide on the inside of fusion machines known as tokamaks can absorb as much deuterium as pure lithium can.


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University of Wisconsin-Milwaukee Joins Energy-Focused National Science Foundation Research Center

The University of Wisconsin-Milwaukee is joining a National Science Foundation-backed research center that will develop new technologies for storing, controlling and distributing energy that could ward off cybersecurity threats and lower energy bills.

Rensselaer Polytechnic Institute Graduates Urged to Embrace Change at 211th Commencement

Describing the dizzying pace of technological innovation, former United States Secretary of Energy Ernest J. Moniz urged graduates to "anticipate career change, welcome it, and manage it to your and your society's benefit" at the 211th Commencement at Rensselaer Polytechnic Institute (RPI) Saturday.

ORNL Welcomes Innovation Crossroads Entrepreneurial Research Fellows

Oak Ridge National Laboratory today welcomed the first cohort of innovators to join Innovation Crossroads, the Southeast region's first entrepreneurial research and development program based at a U.S. Department of Energy national laboratory.

Department of Energy Secretary Recognizes Argonne Scientists' Work to Fight Ebola, Cancer

Two groups of researchers at Argonne earned special awards from the office of the U.S. Secretary of Energy for addressing the global health challenges of Ebola and cancer.

Jefferson Science Associates, LLC Recognized for Leadership in Small Business Utilization

Jefferson Lab/Jefferson Science Associates has a long-standing commitment to doing business with and mentoring small businesses. That commitment and support received national recognition at the 16th Annual Dept. of Energy Small Business Forum and Expo held May 16-18, 2017 in Kansas City, Mo.

Rensselaer Polytechnic Institute President's Commencement Colloquy to Address "Criticality, Incisiveness, Creativity"

To kick off the Rensselaer Polytechnic Institute Commencement weekend, the annual President's Commencement Colloquy will take place on Friday, May 19, beginning at 3:30 p.m. The discussion, titled "Criticality, Incisiveness, Creativity," will include the Honorable Ernest J. Moniz, former Secretary of Energy, and the Honorable Roger W. Ferguson Jr., President and CEO of TIAA, and will be moderated by Rensselaer President Shirley Ann Jackson.

ORNL, University of Tennessee Launch New Doctoral Program in Data Science

The Tennessee Higher Education Commission has approved a new doctoral program in data science and engineering as part of the Bredesen Center for Interdisciplinary Research and Graduate Education.

SurfTec Receives $1.2 Million Energy Award to Develop Novel Coating

The Department of Energy has awarded $1.2 million to SurfTec LLC, a company affiliated with the U of A Technology Development Foundation, to continue developing a nanoparticle-based coating to replace lead-based journal bearings in the next generation of electric machines.

Ames Laboratory Scientist Inducted Into National Inventors Hall of Fame

Iver Anderson, senior metallurgist at Ames Laboratory, has been inducted into the National Inventors Hall of Fame.

DOE HPC4Mfg Program Funds 13 New Projects to Improve U.S. Energy Technologies Through High Performance Computing

A U.S. Department of Energy (DOE) program designed to spur the use of high performance supercomputers to advance U.S. manufacturing is funding 13 new industry projects for a total of $3.9 million.


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Casting a Wide Net

Designed molecules will provide positive impacts in energy production by selectively removing unwanted ions from complex solutions.

New Software Tools Streamline DNA Sequence Design-and-Build Process

Enhanced software tools will accelerate gene discovery and characterization, vital for new forms of fuel production.

The Ultrafast Interplay Between Molecules and Materials

Computer calculations by the Center for Solar Fuels, an Energy Frontier Research Center, shed light on nebulous interactions in semiconductors relevant to dye-sensitized solar cells.

Supercapacitors: WOODn't That Be Nice

Researchers at Nanostructures for Electrical Energy Storage, an Energy Frontier Research Center, take advantage of nature-made materials and structure for energy storage research.

Groundwater Flow Is Key for Modeling the Global Water Cycle

Water table depth and groundwater flow are vital to understanding the amount of water that plants transmit to the atmosphere.

Finding the Correct Path

A new computational technique greatly simplifies the complex reaction networks common to catalysis and combustion fields.

Opening Efficient Routes to Everyday Plastics

A new material from the Inorganometallic Catalyst Design Center, an Energy Frontier Research Center, facilitates the production of key industrial supplies.

Fight to the Top: Silver and Gold Compete for the Surface of a Bimetallic Solid

It's the classic plot of a buddy movie. Two struggling bodies team up to drive the plot and do good together. That same idea, when it comes to metals, could help scientists solve a big problem: the amount of energy consumed by making chemicals.

Saving Energy Through Light Control

New materials, designed by researchers at the Center for Excitonics, an Energy Frontier Research Center, can reduce energy consumption with the flip of a switch.

Teaching Perovskites to Swim

Scientists at the ANSER Energy Frontier Research Center designed a two-component layer protects a sunlight-harvesting device from water and heat.


Saturday May 20, 2017, 12:05 PM

Rensselaer Polytechnic Institute Graduates Urged to Embrace Change at 211th Commencement

Rensselaer Polytechnic Institute (RPI)

Monday May 15, 2017, 01:05 PM

ORNL, University of Tennessee Launch New Doctoral Program in Data Science

Oak Ridge National Laboratory

Friday April 07, 2017, 11:05 AM

Champions in Science: Profile of Jonathan Kirzner

Department of Energy, Office of Science

Wednesday April 05, 2017, 12:05 PM

High-Schooler Solves College-Level Security Puzzle From Argonne, Sparks Interest in Career

Argonne National Laboratory

Tuesday March 28, 2017, 12:05 PM

Champions in Science: Profile of Jenica Jacobi

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Great Neck South High School Wins Regional Science Bowl at Brookhaven Lab

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Wednesday February 15, 2017, 04:05 PM

Middle Schoolers Test Their Knowledge at Science Bowl Competition

Argonne National Laboratory

Friday January 27, 2017, 04:00 PM

Haslam Visits ORNL to Highlight State's Role in Discovering Tennessine

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Internship Program Helps Foster Development of Future Nuclear Scientists

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Friday May 13, 2016, 04:05 PM

More Than 12,000 Explore Jefferson Lab During April 30 Open House

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Monday April 25, 2016, 05:05 PM

Giving Back to National Science Bowl

Ames Laboratory

Friday March 25, 2016, 12:05 PM

NMSU Undergrad Tackles 3D Particle Scattering Animations After Receiving JSA Research Assistantship

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Shannon Greco: A Self-Described "STEM Education Zealot"

Princeton Plasma Physics Laboratory

Monday November 16, 2015, 04:05 PM

Rare Earths for Life: An 85th Birthday Visit with Mr. Rare Earth

Ames Laboratory

Tuesday October 20, 2015, 01:05 PM

Meet Robert Palomino: 'Give Everything a Shot!'

Brookhaven National Laboratory

Tuesday April 22, 2014, 11:30 AM

University of Utah Makes Solar Accessible

University of Utah

Wednesday March 06, 2013, 03:40 PM

Student Innovator at Rensselaer Polytechnic Institute Seeks Brighter, Smarter, and More Efficient LEDs

Rensselaer Polytechnic Institute (RPI)

Friday November 16, 2012, 10:00 AM

Texas Tech Energy Commerce Students, Community Light up Tent City

Texas Tech University

Wednesday November 23, 2011, 10:45 AM

Don't Get 'Frosted' Over Heating Your Home This Winter

Temple University

Wednesday July 06, 2011, 06:00 PM

New Research Center To Tackle Critical Challenges Related to Aircraft Design, Wind Energy, Smart Buildings

Rensselaer Polytechnic Institute (RPI)

Friday April 22, 2011, 09:00 AM

First Polymer Solar-Thermal Device Heats Home, Saves Money

Wake Forest University

Friday April 15, 2011, 12:25 PM

Like Superman, American University Will Get Its Energy from the Sun

American University

Thursday February 10, 2011, 05:00 PM

ARRA Grant to Help Fund Seminary Building Green Roof

University of Chicago

Tuesday December 07, 2010, 05:00 PM

UC San Diego Installing 2.8 Megawatt Fuel Cell to Anchor Energy Innovation Park

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Monday November 01, 2010, 12:50 PM

Rensselaer Smart Lighting Engineering Research Center Announces First Deployment of New Technology on Campus

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Friday September 10, 2010, 12:40 PM

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Ithaca College

Tuesday July 27, 2010, 10:30 AM

Texas Governor Announces $8.4 Million Award to Create Renewable Energy Institute

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Wednesday May 05, 2010, 09:30 AM

National Engineering Program Seeks Subject Matter Experts in Energy

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Microbes Making the Most of Their Energy Sources

Article ID: 673855

Released: 2017-05-01 10:05:50

Source Newsroom: Department of Energy, Office of Science

  • Credit: Image courtesy of Saroj Poudel

    A generalized electron bifurcation reaction. An electron donor provides two electrons that are bifurcated simultaneously to two acceptor molecules with lower energy and higher energy in a hypothetical enzyme.

  • Credit: Image courtesy of Nathan Johnson

    Imagine a blue ball rolls downhill. Normally, it hits the yellow ball at the bottom of the hill, forcing that second sphere to go up the hill. In electron bifurcation, the energy from the blue ball goes into the hill.

Microorganisms are most typically thought of as biological nuisances that cause disease or spoil food. However, bacteria and other microorganisms are responsible for many important processes on Earth, without which the planet would be uninhabitable for any form of life.

Microorganisms can even be used to help bridge the gap towards more abundant and economical energy sources. This can occur by microbes that naturally generate biofuels such as hydrogen gas and methane. They can also be engineered to produce other biofuels such as butanol and biodiesel.

The key is that microorganisms need to harness, or conserve, energy in order to live — as all life does. It just so happens that they can also provide useful byproducts — resultant from their unique means of energy conservation — such as biofuels.

One mechanism of energy conservation — termed electron bifurcation — was not discovered until as recently as 2008. Before this discovery, there were only two known ways that life forms can conserve energy.

Several key biofuel targets for next-generation energy development are reliant on electron bifurcation as a means of energy conservation. As a result, this discovery ignited interest from the Department of Energy due to its relevance in hitting targets for next-generation energy development.

Now scientists at the Biological Electron Transfer and Catalysis (BETCy) Energy Frontier Research Center are beginning to understand how this process works and how it can aid in meeting next-generation energy demands.

Harnessing energy through electron bifurcation. To understand how electron bifurcation can be leveraged in biofuels research, an understanding of how it works is necessary.

A unifying theme of all life is that energy must be acquired to fuel biochemical processes that require energy. This is accomplished by coupling reactions that are favorable and provide energy, known as exergonic reactions, to reactions that are unfavorable and require energy input, known as endergonic reactions.

Imagine a blue ball rolls downhill. Normally, it hits the yellow ball at the bottom of the hill, forcing that second sphere to go up the hill. The energy is transferred between the two spheres in this example. In electron bifurcation, the hill, or enzyme, itself mediates this energy transfer from the blue ball to the yellow ball. In the ball analogy, the energy would power an escalator that simultaneously takes the yellow ball up the hill. The hill manages the energy transfer and separates the motion of both balls, allowing both events to occur instantaneously and separately. 

Electron bifurcation is similar in this regard. It is unique, however, in that the energy released from the exergonic reaction involves the direct transfer of electrons, and energy is conserved to simultaneously power the unfavorable reaction that also involves the direct transfer of electrons.

To conceptualize electron bifurcation, imagine two hills with a ball at the top of one hill and one in between the hills. By pushing the first one downhill, the impact pushes the other ball up the other hill. However, this process happens simultaneously in electron bifurcation. Perhaps more directly analogous, imagine the first ball is rolled downhill and that energy is transferred to the hill where it powers an escalator that simultaneously conveys the second ball up the other hill. The hill, in this example, mediates the energy transfer and separates the movements of both balls.

Analogously, electron bifurcation proceeds through the simultaneous transfer of electrons to both exergonic (downhill) and endergonic (uphill) reaction pathways. The process occurs within a single protein structure, or enzyme, that consists of multiple protein components, or subunits. Recalling the above example, the enzyme acts as the hill that mediates energy transfer. By coupling the two electron transfer reactions within a single enzyme simultaneously, energy loss that would otherwise escape as heat is minimized. Efficiency is critical for bifurcation because the organisms that perform it tend to live in environments where there is little energy. Thus, every bit of energy that is harnessed is crucial for survival.

Understanding the mechanisms behind electron bifurcation. Unraveling the mechanisms that allow electron bifurcation to occur in microorganisms has clear biotechnological and bio-energy implications. Understanding how microorganisms minimize energy loss during chemical reactions will enable the design of more efficient bio-inspired energy technologies. More directly, several electron bifurcating enzymes are important biotechnological and bio-energy targets. Gaining insight into how these enzymes function at the molecular level will provide a framework for enhancing their utilization in energy science.

Scientists at the BETCy Energy Frontier Research Center are investigating hydrogenases, which are a type of bifurcating enzyme that catalyze the production of hydrogen gas during cellular metabolism in microorganisms. Hydrogenases display high rates of hydrogen production and are thus highly sought-after bio-energy targets. This microbially produced hydrogen can then be harnessed and used as an alternative fuel source.

Interestingly, some hydrogenases catalyze hydrogen production through electron bifurcation (or rather, a version of bifurcation that operates in reverse as the above example). Yet, other than the discovery of the process in hydrogenases, little is known about how it occurs at the molecular level.

Recently, BETCy scientists compared the gene and protein repertoires of microbes that contain hydrogenases (bifurcating and non-bifurcating). The team’s goal was to better understand which hydrogenase enzyme components are determinants of the ability to bifurcate. These comparisons indicated that, aside from the enzyme subunit that catalyzes hydrogen production, additional enzyme protein components were likely necessary for bifurcating ability.

The team found that the presence of protein subunits that contain specific electron transferring inorganic components (coordinated iron and sulfur molecules) appear to be one key to bifurcation. In addition, organic electron transferring subunits (termed flavins — naturally occurring pigments) also appeared to be key to bifurcation ability. In other types of bifurcating enzymes, these electron transferring protein components are also almost certainly integral to the bifurcating process.

Untangling how electrons taken from a single source are sent down two different transfer pathways is a major focus of bifurcation research. Naturally, electrons should be transferred through the exergonic (downhill) pathway without active interference, forcing them towards the endergonic (uphill) pathway. One idea being investigated by BETCy involves an electron “gating” mechanism. Gating by the protein subunits would allow the transfer and separation of each set of electrons towards endergonic and exergonic pathways. This is where the iron-sulfur and flavin electron transfer components of the enzymes become important. These co-factors then mediate the transfer of electrons through each of these pathways.

Thus, analogous to the ball and hill example, the first electron transfer downhill would drive an enzyme change that simultaneously forces the other electron up the other hill.

Clearly, electron bifurcation represents an intriguing energy transfer process in biology. Understanding how this process occurs, as the BETCy team is investigating, promises significant advances in understanding biological energy transfer. Further, a more complete understanding of these processes holds substantial promise for bio-inspired energy advances.

Acknowledgments: 

Peters et al. This work was supported as part of the Biological Electron Transfer and Catalysis (BETCy) Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. P.W.K. was supported by the U.S. Department of Energy contract with the National Renewable Energy Laboratory.

Poudel et al. This work was supported as part of the Biological Electron Transfer and Catalysis Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. The mass spectrometry facility at Montana State University receives funding from the Murdock Charitable Trust and National Institutes of Health of the Centers of Biomedical Research Excellence program.

More Information: 

Peters JW, AF Miller, AK Jones, PW King, and MW Adams. 2016. “Electron Bifurcation.” Current Opinion in Chemical Biology 31:146-152. DOI: 10.1016/j.cbpa.2016.03.007

Poudel S, M Tokmina-Lukaszewska, DR Colman, M Refai, GJ Schut, PW King, PC Maness, MW Adams, JW Peters, B Bothner, and ES Boyd. 2016. “Unification of [FeFe]-Hydrogenases into Three Structural and Functional Groups.” Biochimica et Biophysica Acta 1860(9):1910-1921. DOI: 10.1016/j.bbagen.2016.05.034

This item, written by Dan Colman, is part of Frontiers in Energy Research, a newsletter for the Energy Frontier Research Centers created by early career members of the centers. See http://www.energyfrontier.us/newsletter/