ees 2019
17 November 2016 2016 01:04 PM GMT

NREL Scientists Discover How Bacterium Uses CO2 And Cellulose To Make Biofuels

Scientists at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) made the surprise discovery that a metabolic pathway to take up CO2 exists and functions in a microorganism capable of breaking down and fermenting cellulosic biomass to produce biofuels including hydrogen and hydrocarbons.

Clostridium thermocellum is among the most efficient bacteria indirectly converting cellulosic materials into hydrogen and hydrocarbons biofuels. Most bacteria feeding upon organic carbon compounds, such as glucose or xylose, release CO2 as a waste byproduct, decreasing the maximum amount of products the microorganism can produce per carbon atom measured as carbon efficiency.

Other scientists have found the addition of a form of CO2, known as bicarbonate, into the medium containing the bacterium actually promotes the growth of C. thermocellum, yet its mechanistic details remained a puzzle. This enhanced growth implied the bacterium had the ability to use CO2 and prompted NREL researchers to investigate the phenomena enhancing the bacterium’s growth.

“It took us by surprise that this microbe can recapture some of the CO2 released during growth while they consume sugars derived from cellulosic biomass,” said Katherine J. Chou, a staff scientist with NREL’s Photobiology group and co-author of the new paper “CO2-fixing one-carbon metabolism in a cellulose-degrading bacterium Clostridium thermocellum.” The research is in the new issue of the journal Proceedings of the National Academy of Sciences of the United States of America.

Using carbon isotopes coupled with mass spectrometry analysis, the researchers were able to track how CO2enters the cell, identify the enzymes critical to CO2 uptake, and how CO2 incorporates into products thereby discovering a new metabolic route unknown to the scientific community. Many species of bacteria have the pathway in place for CO2 uptake, but before the new research, the pathway was not associated with the role of carbon dioxide assimilation (otherwise known as CO2 fixation).

The pathway enables the bacterium to use both CO2 and organic carbons during its growth, which is counter-intuitive because it’s much more common for this type of organism to use one and not the other, especially in heterotrophic microbes.

NREL researchers and their collaborators determined adding bicarbonate increased the apparent carbon efficiency of C. thermocellum from 65.7 percent to 75.5 percent. The finding underscores the metabolic plasticity of the microbe and raises various possibilities on how the bacterium is able to use both organic carbons and CO2 without breaking the rules of thermodynamics in energy conservation. The discovery also provides a paradigm shift in the fundamental understandings of carbon metabolism in a cellulose degrading bacterium.

“Our findings pave the way for future engineering of the bacterium as a way to improve carbon efficiency and to reduce the amount of CO2 released into the environment,” Chou said. With the observed improved carbon efficiency, this work inspires future research to redirect more cellular electrons in support of increased hydrogen production, a key goal for the funded research. In addition to Chou, the co-authors from NREL are Wei Xiong, Lauren Magnusson, Lisa Warner, and Pin-Ching Maness. Two BioEnergy Science Center (BESC) co-authors are Paul Lin and James Liao from the University of California, Los Angeles, where Chou earned her Ph.D. in chemical and biomolecular engineering.

The latest research into the bacterium was financed by the NREL Director’s Fellowship Program, Energy Department’s Fuel Cell Technologies Office, as well as Office of Biological and Environmental Research in the DOE Office of Science. NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

Photo: Courtesy of National Renewable Energy Laboratory (NREL)

May 30th 2019
Battery Boom: Wind And Solar Can Generate Half Of Worldwide Electricity By 2050

Coal is to shrink to just 11% of global electricity generation by mid-century, from 38% now, as costs shift heavily in favour of wind, solar and batteries. Wind and solar are set to surge to almost “50 by 50” – 50% of world generation by 2050 due to reductions in cost. “Cheap battery storage means that it becomes increasingly possible to finesse the delivery of electricity from wind and solar so that these technologies can help meet demand even when the wind isn’t blowing and the sun isn’t shining. The result will be renewables eating up more and more of the existing market for coal, gas and nuclear.”

November 27th 2018
Solar And Wind Provide 100% Of New Generating Capacity Additions In September

US – According to an analysis by the SUN DAY Campaign of data just released by the Federal Energy Regulatory Commission (FERC), solar and wind were the only energy sources adding new capacity to the U.S. electricity generation mix in September. Three “units” of new wind accounted for 363-MW while nine units of solar provided 339-MW.

May 29th 2019
Arsenal Unveil Battery Storage System: First Of Its Kind At A UK Football Club

Arsenal Football Club has unveiled a battery storage system (BSS) to store enough energy to run the 60,000 seater Emirates Stadium from kick-off to full time. It follows a unique collaboration with Pivot Power to install a 2MW/2.5MWh lithium ion BSS, with funds managed by Downing LLP. The project, the first of its kind in the UK, will also save club money as it works to support low-carbon plans. The BSS allows Arsenal to avoid peak power prices, buying electricity when it is cheap and storing it for use when prices are high. Typically, energy can cost three times more at peak times than overnight. The installation maintains Arsenal as the leader in sustainability in sport following its commitment to clean energy with Octopus Energy in 2016.

May 18th 2019
Wind: China Maintains Emerging Markets Top Spot Following 19.7GW Build Boom

Wind industry intelligence service A Word About Wind has launched its Emerging Markets Attractiveness Index report for 2018, which provides insight and analysis into the most attractive emerging markets for wind companies. The index, now in its second year, ranks the top 30 emerging markets that investors should consider when investing in wind in Europe, Africa, Asia and Latin America. The list considers factors including political and economic stability for investors, alongside the growth of electricity demand and potential for wind growth, in order to rank the countries by overall potential. As with last year’s report, China tops the list and the ongoing trade war with the US shows no sign of slowing China’s formidable growth.

May 30th 2019
EU Approves Ambitious Energy Efficiency Goals, Encourages Clean Energy Feed-In

Europeans will now be entitled to consume, store and sell the renewable energy they produce in line with ambitious targets set by the EU. The targets are to be reviewed by 2023, and can only be raised, not lowered. By making energy more efficient, Europeans will see their energy bills reduced. In addition, Europe will reduce its reliance on external suppliers of oil and gas, improve local air quality and protect the climate. For the first time, member states will also be obliged to establish specific energy efficiency measures to the benefit of those affected by energy poverty. Member states must also ensure that citizens are entitled to generate renewable energy for their own consumption, to store it and to sell excess production.

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