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Oak Ridge, TN, United States

BioEnergy Science Center

Oak Ridge, TN, United States
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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 CO 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 in directly converting cellulosic materials into hydrogen and hydrocarbons biofuels. Most bacteria feeding upon organic carbon compounds, such as glucose or xylose, release CO 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 CO , 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 CO 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 CO 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 "CO -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 CO enters the cell, identify the enzymes critical to CO uptake, and how CO incorporates into products thereby discovering a new metabolic route unknown to the scientific community. Many species of bacteria have the pathway in place for CO uptake, but before the new research, the pathway was not associated with the role of carbon dioxide assimilation (otherwise known as CO fixation). The pathway enables the bacterium to use both CO 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 CO 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 CO 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.


News Article | November 3, 2016
Site: www.sciencedaily.com

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 CO 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 in directly converting cellulosic materials into hydrogen and hydrocarbons biofuels. Most bacteria feeding upon organic carbon compounds, such as glucose or xylose, release CO 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 CO , 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 CO 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 CO 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 "CO -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 CO enters the cell, identify the enzymes critical to CO uptake, and how CO incorporates into products thereby discovering a new metabolic route unknown to the scientific community. Many species of bacteria have the pathway in place for CO uptake, but before the new research, the pathway was not associated with the role of carbon dioxide assimilation (otherwise known as CO fixation). The pathway enables the bacterium to use both CO 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 CO 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 CO 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.


Clostridium thermocellum is among the most efficient bacteria in directly converting cellulosic materials into hydrogen and hydrocarbons biofuels. Most bacteria feeding upon organic carbon compounds, such as glucose or xylose, release CO 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 CO , 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 CO 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 CO 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 "CO -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 CO enters the cell, identify the enzymes critical to CO uptake, and how CO incorporates into products thereby discovering a new metabolic route unknown to the scientific community. Many species of bacteria have the pathway in place for CO uptake, but before the new research, the pathway was not associated with the role of carbon dioxide assimilation (otherwise known as CO fixation). The pathway enables the bacterium to use both CO 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 CO 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 CO 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. Explore further: Team explains the higher cellulolytic activity of a vital microorganism More information: Wei Xiong et al. CO-fixing one-carbon metabolism in a cellulose-degrading bacterium, Proceedings of the National Academy of Sciences (2016). DOI: 10.1073/pnas.1605482113


News Article | January 14, 2016
Site: www.greencarcongress.com

« Automotive sales in Russia in 2015 down 35.7% | Main | VW e-Golf to be enhanced with improved infotainment, connectivity and range » A new comparative study by researchers at the Department of Energy’s BioEnergy Science Center (BESC), based at Oak Ridge National Laboratory, finds the natural abilities of unconventional bacteria could help boost the efficiency of cellulosic biofuel production. A team of researchers from five institutions analyzed the ability of six microorganisms to solubilize potential bioenergy feedstocks such as switchgrass that have evolved strong defenses against biological and chemical attack. Solubilization prepares the plant feedstocks for subsequent fermentation and, ultimately, use as fuel. While the ability to achieve significant solubilization of minimally pretreated switchgrass is widespread, they found a five-fold difference between the most- and least-effective biocatalyst—feedstock combinations. The paper, published in Biotechnology for Biofuels, is the most comprehensive comparative study of its type to date, the authors said. Their analysis demonstrated that under carefully controlled conditions, a microbe called Clostridium thermocellum is twice as effective as fungal enzymes used by industry today. The researchers also tested the different microbes’ performance with minimal pretreatment of the plant materials, indicating it may be possible to reduce or eliminate use of heat and chemicals that make the feedstock accessible to biological processing. The researchers note that the study was designed to provide indications of intrinsic capability and performance under industrial conditions. They hope their findings will guide the development of advanced processes to lower costs and improve the efficiency of commercial biofuel production. Although promising, further work is required to translate these results into industrial practice. In particular, the biocatalysts we found to be most effective at solubilizing biomass are non-model microorganisms for which limited molecular tools are available and extensive development and testing under industrial conditions are required, e.g. with respect to solids loading. In addition, optimization, innovation, and evaluation pursuant to a diversity of co-treatment strategies in conjunction with these biocatalysts have yet to be undertaken. The research team also considered the use of mechanical disruption techniques such as milling to complement the microorganisms’ biological breakdown. Coauthors are Dartmouth College’s Lee Lynd, Julie Paye, Anna Guseva and Sarah Hammer; the National Renewable Energy Laboratory’s Erica Gjersing, Mark Davis, Jessica Olstad, Bryon Donohoe; ORNL’s Brian Davison; Thanh Yen Nguyen and Charles Wyman of the University of California, Riverside; and University of Georgia’s Sivakumar Pattathil and Michael Hahn. BESC is a Department of Energy Bioenergy Research Center supported by DOE’s Office of Science.


News Article | March 7, 2016
Site: www.greencarcongress.com

« Comet Biorefining awarded C$10.9M SDTC grant for bio-based chemicals plant | Main | UT, Oak Ridge scientists gain new insights into atomic disordering of complex metal oxides; materials for energy applications » Three US Department of Energy-funded research centers—the BioEnergy Science Center (Oak Ridge National Laboratory); the Great Lakes Bioenergy Research Center (University of Wisconsin–Madison and Michigan State University); and the Joint BioEnergy Institute (Lawrence Berkeley National Laboratory) (earlier post)—reported the disclosure of their 500th invention. Created in 2007, the Bioenergy Research Centers (BRCs) work together to address the most significant challenges standing in the way of affordable, sustainable and scalable advanced liquid transportation fuels. In their focus on producing biofuels from cellulosic biomass (i.e., wood, grasses and the inedible parts of plants), the BRCs are developing a portfolio of new bio-based products, methods and tools for use in the biofuels industry. Great Lakes Bioenergy Research Center Director Tim Donohue credits the BRCs’ continued success to its multidisciplinary research model, which brings together a diverse group of experts, including ecologists, economists, engineers, plant biologists, microbiologists, computational scientists and chemists. Enabled by a broad range of genome-driven research methods, the BRCs’ technologies represent a variety of approaches to different bottlenecks in the current biofuel pipeline. Some technologies focus on improved ways of breaking down biomass for conversion into fuel, some on engineering plants with the characteristics most advantageous for biofuels, and still others on creating co-products that can help make advanced biofuels economically viable. That variety, however, does not represent a lack of focus. BioEnergy Science Center Director Paul Gilna points to the 500 invention disclosures as proof of the BRCs’ progress, focusing on the role the BRCs are playing in creating a broad knowledgebase for future biofuels technologies. Joint BioEnergy Institute Chief Executive Officer Jay Keasling praised the pioneering efforts of the BRCs and their role in envisioning a future in which cellulosic biofuels provide transformative advantages. BRC research is supported by the US Department of Energy’s Office of Science. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.


« DOE’s Office of Technology Transitions issues first call to launch new energy technologies from national laboratories to market | Main | Gasoline consumption in California rose 2.4% during FY 2014-15; largest yearly increase in a decade » Researchers at the Energy Department’s National Renewable Energy Laboratory (NREL) and the BioEnergy Science Center (BESC) have discovered a new cell-free cellulosomal system in Clostridium thermocellum—the most efficient single biomass degrader characterized to date —that is not tethered to the bacterial cell wall and is independent of the primary (tethered) cellulosomes. Their discovery was made during an investigation into the performance of C. thermocellum. The scientists found the microorganism utilizes the common cellulase degradation mechanisms known today (free enzymes and scaffolded enzymes—i.e., a structured architecture of enzymes—attached to the cell), and a new category of scaffolded enzymes not attached to the cell. Reported in an open-access paper in Science Advances, the finding could lead to cheaper production of cellulosic ethanol and other advanced biofuels. The anaerobic bacterium C. thermocellum is a major candidate for the production of biofuels from biomass feedstocks because it already possesses both an external cellulase system and the internal metabolic pathways to convert biomass to ethanol. C. thermocellum is ubiquitous and has been isolated from soil, compost, herbivores, and hot springs. C. thermocellum uses both a free-enzyme system and a tethered cellulosomal system (cellulosome) wherein carbohydrate active enzymes (CAZymes) are organized by primary and secondary scaffoldin proteins to generate large protein complexes attached to the bacterial cell wall. BESC researchers at NREL used newly published cloning strategies, enabled by a collaboration with Dartmouth College, to probe the importance of the primary and secondary scaffoldins of C. thermocellum using scaffoldin deletion strains. They found the scaffoldins were essential to the cell wall defibrillation mechanism used by C. thermocellum. Native cellulosomes are capable of creating or at least maintaining increased substrate surface area during deconstruction by splaying and dividing the biomass particles. This ability is completely lost with any modification of these cellulosomes, such as the removal of the primary or secondary scaffoldins. Using the same mutant strains as background, they also found a new type of enzyme assembly that is not tethered to the cell and allows the microorganism more freedom to explore for additional biomass or provides a redundancy in its cellulolytic system to assure a consistent source of sugars. The researchers suggested that the cell-free cellulosome complex can be seen as a “long range cellulosome” because it can diffuse away from the cell and degrade polysaccharide substrates remotely from the bacterial cell. They found that the primary scaffoldin played the most important role in cellulose degradation by C. thermocellum, whereas the secondary scaffoldins have less important roles. Additionally, the distinct and efficient mode of action of the C. thermocellum exoproteome, wherein the cellulosomes splay or divide biomass particles, changes when either the primary or secondary scaffolds are removed, showing that the intact wild-type cellulosomal system is necessary for this essential mode of action. This discovery, enabled by the BioEnergy Science Center, will influence the strategies used to improve the cellulolytic activity of biomass degrading microbes going forward. First author of the paper was NREL scientist Qi Xu. Others from NREL include Michael G. Resch, Kara Podkaminer, Shihui Yang, John O. Baker, Bryon S. Donohoe, Stephen R. Decker, Michael E. Himmel, and Yannick J. Bomble. Other authors from the BioEnergy Science Center are Charlotte Wilson, Dawn M. Klingeman, Daniel G. Olson, Richard J. Giannone, Robert L. Hettich, Steven D. Brown, Lee R. Lynd, and Edward A. Bayer.


News Article | December 7, 2016
Site: www.eurekalert.org

To arrange for an interview with a researcher, please contact the Communications staff member identified at the end of each tip. For more information on ORNL and its research and development activities, please refer to one of our media contacts. If you have a general media-related question or comment, you can send it to news@ornl.gov. New Mexico's Almeria Analytics has added a suite of Oak Ridge National Laboratory software technologies to its arsenal of tools useful for disaster relief, civil engineering, urban planning and homeland security applications. Piranha, Raptor and DTHSTR combined with ORNL's VERDE, licensed last year by Almeria, will allow the company to create a software package that can quickly and efficiently search millions of documents in minutes. Almeria provides real-time status of infrastructure during significant events. "We generate a lot of documents from real-time sensor and reporting feeds, so by adding this capability we will be able to further refine our real-time reporting capabilities," said Steve Fernandez of Almeria Analytics. [Contact: Ron Walli, (865) 576-0226; wallira@ornl.gov] Caption: With Piranha, Almeria Analytics can make sense of vast amounts of data in mere minutes. A technology being developed at Oak Ridge National Laboratory could be a valuable tool for urban planning, emergency management and understanding where people are and how they move. Researchers are developing a wireless sensor network that uses signals from cell towers to examine population density in real time, which is important to understand accessibility and livability in urban areas. "Our system works by passively capturing cell tower signals with a radio frequency antenna tuned to specific frequency bands," said ORNL's Teja Kuruganti, one of the developers. Researchers expect this technology to be useful for LandScan and other population databases. [Contact: Ron Walli, (865) 576-0226; wallira@ornl.gov] Caption: ORNL's wireless sensor network provides researchers with an accurate index of population density in half-hour increments. Researchers at Oak Ridge National Laboratory have developed a novel, nontoxic fluorescent air leak detection system that can find cracks in walls and roofs in existing and new buildings. In laboratory experiments, ORNL's Diana Hun and Brenda Smith used an off-the-shelf humidifier to release a water-based solution of commercially available riboflavin, or Vitamin B2, supplement against a plywood wall with cracks. When the room was pressurized, tiny vitamin droplets were pulled to the leak points where they accumulated. The vitamins remained invisible unless revealed under ultraviolet light when they fluoresced. "Our system is ideal for occupied buildings, because the solution won't harm furniture, for instance, plus the vitamin particles are not visible or harmful to occupants," Hun said. Repair of a leaky home could yield a $450 per year energy savings with a 2.5-year payback. The ORNL-developed system could be used in other spaces such as storage containers. [Contact: Sara Shoemaker, (865) 576-9219; shoemakerms@ornl.gov] Caption: ORNL's novel, nontoxic fluorescent air leak detection system uses a vitamin- and water-based solution to quickly locate cracks in occupied buildings without damaging property. A new motor developed by researchers at Oak Ridge National Laboratory achieved 75 percent higher power than a comparably sized commercial motor for electric vehicles. The prototype motor uses ferrite, iron-based, permanent magnets instead of the expensive imported rare earth permanent magnets common in motors today. "We are focused on increasing energy security for the nation by designing efficient high performance motors built with materials that are both economical and abundantly available here in the United States," said ORNL's Tim Burress. "We've demonstrated a peak power of 103 kilowatts so far, and we are still fine tuning the motor design." [Contact: Kim Askey, (865) 946-1861; askeyka@ornl.gov] Caption: Oak Ridge National Laboratory researcher Tim Burress works with a prototype motor that generates 75 percent more power than comparable commercial motors without the use of rare earth materials. A new microscopy technique developed at Oak Ridge National Laboratory enables rapid measurement of the dynamic state of materials used in memory storage and allows "imaging" of this phenomenon with unprecedented resolution (approximately 10 nanometers). The technique, detailed in Nature Communications, acquires the complete information from the microscope sensor that facilitates the extraction of material properties thousands of times faster than the current state of the art. The increased measurement and imaging speed provides a new window for understanding complex and dynamic material properties. Scientists are using this technique to study materials that are promising candidates for the next generation of electronic computing and storage devices. [Contact: Sara Shoemaker, (865) 576-9219; shoemakerms@ornl.gov] Caption: ORNL scientists developed a new microscopy technique that provides high-resolution images of nanomaterial behavior thousands of times faster than current techniques. Livestock may soon be getting more nutrition from forage feed thanks to an invention from the BioEnergy Science Center at Oak Ridge National Laboratory and partners at the University of Tennessee and West Virginia University. Working with a population of poplar trees, the scientists identified a gene that regulates the production of lignin, the material that lends plants rigidity. By altering lignin synthesis, the gene can decrease lignin content and increase desirable flavonoids, resulting in plants that are easier to digest and more nutritious. Preliminary studies showed that the genetic mechanism has the same effect in Medicago truncatula, a model system for alfalfa, which is widely used for animal feed. "We've achieved decreases in lignin of up to 25 percent and increases in flavonoid content of more than 250 percent using this genetic mechanism," said ORNL lead researcher Wellington Muchero. Forage Genetics International, a major supplier of alfalfa seed, has licensed the technology and will evaluate it for commercial use in animal feed. [Contact: Kim Askey, (865) 946-1861; askeyka@ornl.gov] Caption: Oak Ridge National Laboratory researchers Sara Jawdy (left) and Lee Gunter evaluate the growth of rice plants carrying a genetic mechanism that reduces lignin and increases flavonoids.


News Article | January 14, 2016
Site: phys.org

The microbe Clostridium thermocellum (stained green), seen growing on a piece of poplar biomass, is among several microorganisms recently evaluated in a BioEnergy Science Center comparative study. Credit: Jennifer Morrell-Falvey, Oak Ridge National Laboratory. Researchers at the Department of Energy's BioEnergy Science Center are looking beyond the usual suspects in the search for microbes that can efficiently break down inedible plant matter for conversion to biofuels. A new comparative study from the Oak Ridge National Laboratory-based center finds the natural abilities of unconventional bacteria could help boost the efficiency of cellulosic biofuel production. A team of researchers from five institutions analyzed the ability of six microorganisms to solubilize potential bioenergy feedstocks such as switchgrass that have evolved strong defenses against biological and chemical attack. Solubilization prepares the plant feedstocks for subsequent fermentation and, ultimately, use as fuel. The paper, published in Biotechnology for Biofuels, is the most comprehensive comparative study of its type to date. "Starting with nature's best biomass-solubilizing systems may enable a reduction in the amount of nonbiological processing required to produce biofuels," said ORNL coauthor Brian Davison. "We're asking the question—what are nature's best biocatalysts?" Their analysis demonstrated that under carefully controlled conditions, a microbe called Clostridium thermocellum is twice as effective as fungal enzymes used by industry today. The researchers also tested the different microbes' performance with minimal pretreatment of the plant materials, indicating it may be possible to reduce or eliminate use of heat and chemicals that make the feedstock accessible to biological processing. "Eliminating both enzyme addition and conventional pretreatment is a potential game-changer," said Dartmouth engineering professor Lee Lynd, the study's corresponding author. The researchers note that the study was designed to provide indications of intrinsic capability and performance under industrial conditions. They hope their findings will guide the development of advanced processes to lower costs and improve the efficiency of commercial biofuel production. "One of the directions that this study leads is that we might have to go out into nature to find the best bugs, even if they are not the ones we're most familiar with," Lynd said. "A major thrust in BESC is that we exclusively focus on these non-standard microorganisms that bring strong biocatalytic abilities to the table, rather than focusing on well-known microorganisms." The research team also considered the use of mechanical disruption techniques such as milling to complement the microorganisms' biological breakdown. The study is published as "Biological lignocellulose solubilization: Comparative evaluation of biocatalysts and enhancement via cotreatment." Explore further: Microbe produces ethanol from switchgrass without pretreatment More information: Julie M. D. Paye et al. Biological lignocellulose solubilization: comparative evaluation of biocatalysts and enhancement via cotreatment, Biotechnology for Biofuels (2016). DOI: 10.1186/s13068-015-0412-y


News Article | January 14, 2016
Site: www.rdmag.com

Researchers at the Department of Energy's BioEnergy Science Center are looking beyond the usual suspects in the search for microbes that can efficiently break down inedible plant matter for conversion to biofuels. A new comparative study from the Oak Ridge National Laboratory-based center finds the natural abilities of unconventional bacteria could help boost the efficiency of cellulosic biofuel production. A team of researchers from five institutions analyzed the ability of six microorganisms to solubilize potential bioenergy feedstocks such as switchgrass that have evolved strong defenses against biological and chemical attack. Solubilization prepares the plant feedstocks for subsequent fermentation and, ultimately, use as fuel. The paper, published in Biotechnology for Biofuels, is the most comprehensive comparative study of its type to date. "Starting with nature's best biomass-solubilizing systems may enable a reduction in the amount of nonbiological processing required to produce biofuels," said ORNL coauthor Brian Davison. "We're asking the question -- what are nature's best biocatalysts?" Their analysis demonstrated that under carefully controlled conditions, a microbe called Clostridium thermocellum is twice as effective as fungal enzymes used by industry today. The researchers also tested the different microbes' performance with minimal pretreatment of the plant materials, indicating it may be possible to reduce or eliminate use of heat and chemicals that make the feedstock accessible to biological processing. "Eliminating both enzyme addition and conventional pretreatment is a potential game-changer," said Dartmouth engineering professor Lee Lynd, the study's corresponding author. The researchers note that the study was designed to provide indications of intrinsic capability and performance under industrial conditions. They hope their findings will guide the development of advanced processes to lower costs and improve the efficiency of commercial biofuel production. "One of the directions that this study leads is that we might have to go out into nature to find the best bugs, even if they are not the ones we're most familiar with," Lynd said. "A major thrust in BESC is that we exclusively focus on these non-standard microorganisms that bring strong biocatalytic abilities to the table, rather than focusing on well-known microorganisms." The research team also considered the use of mechanical disruption techniques such as milling to complement the microorganisms' biological breakdown. The study is published as "Biological lignocellulose solubilization: Comparative evaluation of biocatalysts and enhancement via cotreatment."


News Article | January 15, 2016
Site: www.renewableenergyworld.com

A new comparative study from the Oak Ridge National Laboratory-based BioEnergy Science Center has found that the natural abilities of unconventional bacteria could help boost the efficiency of cellulosic biofuel production.

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