The current production of ethanol relies on the use of expensive enzymes that break down complex plant materials to yield sugars that are fermented into ethanol. One suggested cheaper alternative is consolidated bioprocessing, a streamlined process that uses microorganisms to break down the resistant biomass.
"Consolidated bioprocessing is like a one-pot mix," said Oak Ridge National Laboratory's Richard Giannone, coauthor on a BESC proteomics study that looked at one microorganism candidate. "You want to throw plant material into a pot with the microorganism and allow it to degrade the material and produce ethanol at the same time."
The BESC study focused on Caldicellulosiruptor obsidiansis, a naturally occurring bacterium discovered by BESC scientists in a Yellowstone National Park hot spring. The microorganism, which thrives at extremely high temperatures, breaks down organic material such as sticks and leaves in its natural environment, and scientists hope to transfer this capability to biofuel production tanks.
In a paper featured on the cover of the Journal of Proteome Research, the BESC team conducted a comparative analysis of proteins from C. obsidiansis grown on four different carbon sources, ranging from a simple sugar to more complex substrates such as pure cellulose and finally to switchgrass. The succession of carbon substrates allowed researchers to compare how the organism processes increasingly complex materials.
"This progression helps us look at how proteins change given different carbon substrates," Giannone said. "One of the goals is to identify new proteins that we haven't seen before. If an unknown protein doesn't show up on the simple sugars or cellulose, but it shows up on the switchgrass, then we can say something about that gene or protein—that it responds to something the switchgrass is providing."
The researchers found that growth on switchgrass prompted the organism to express an expanded set of proteins that deal specifically with the hemicellulose content of the plant, including hemicellulose-targeted glycosidases and extracellular solute-binding proteins. Acting together, these two sub-systems work to break down the plant material and import the resulting sugars into the cell. The scientists went on to show that once inside the cell, the organism "switches on" certain enzymes involved in pentose metabolism in order to further process these hemicellulose-derived sugars into usable energy.
"By comparing how C. obsidiansis reacted to switchgrass, relative to pure cellulose, we were able to pinpoint the specific proteins and enzymes that are important to plant cell wall deconstruction—a major roadblock to the production of advanced biofuels," Giannone said.
The team's measurement of the full complement and abundance of C. obsidiansis proteins, called proteomics, can now be combined with other technologies such as genomics, transcriptomics and metabolomics in order to obtain a 360-degree, system-wide view of the organism. Instead of studying discrete proteins, these systems biology-type approaches provide more thorough insight into the day-to-day operations of bioenergy-relevant organisms and thus better equip researchers to make recommendations about their use in ethanol production.
"One goal for us at the BioEnergy Science Center is to take these 'omic' technologies and integrate the data so we can draw definitive conclusions about a system," Giannone said.
Coauthors on the paper are Hamburg University of Technology's Adriane Lochner and Garabed Antranikian, and ORNL's Martin Keller, David Graham and Robert Hettich. The full publication is available here: http://pubs.acs.org/doi/abs/10.1021/pr200536j.
BESC is one of three DOE Bioenergy Research Centers established by the DOE's Office of Science in 2007. The centers support multidisciplinary, multi-institutional research teams pursuing the fundamental scientific breakthroughs needed to make production of cellulosic biofuels, or biofuels from nonfood plant fiber, cost-effective on a national scale. The three centers are coordinated at ORNL, Lawrence Berkeley National Laboratory and the University of Wisconsin-Madison in partnership with Michigan State University.
ORNL is managed by UT-Battelle for the Department of Energy's Office of Science. DOE's 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 http://science.energy.gov.
Morgan McCorkle | EurekAlert!
If Machines Could Smell ...
19.07.2019 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA
Algae-killing viruses spur nutrient recycling in oceans
18.07.2019 | Rutgers University
Adjusting the thermal conductivity of materials is one of the challenges nanoscience is currently facing. Together with colleagues from the Netherlands and Spain, researchers from the University of Basel have shown that the atomic vibrations that determine heat generation in nanowires can be controlled through the arrangement of atoms alone. The scientists will publish the results shortly in the journal Nano Letters.
In the electronics and computer industry, components are becoming ever smaller and more powerful. However, there are problems with the heat generation. It is...
Scientists have visualised the electronic structure in a microelectronic device for the first time, opening up opportunities for finely-tuned high performance electronic devices.
Physicists from the University of Warwick and the University of Washington have developed a technique to measure the energy and momentum of electrons in...
Scientists at the University Würzburg and University Hospital of Würzburg found that megakaryocytes act as “bouncers” and thus modulate bone marrow niche properties and cell migration dynamics. The study was published in July in the Journal “Haematologica”.
Hematopoiesis is the process of forming blood cells, which occurs predominantly in the bone marrow. The bone marrow produces all types of blood cells: red...
For some phenomena in quantum many-body physics several competing theories exist. But which of them describes a quantum phenomenon best? A team of researchers from the Technical University of Munich (TUM) and Harvard University in the United States has now successfully deployed artificial neural networks for image analysis of quantum systems.
Is that a dog or a cat? Such a classification is a prime example of machine learning: artificial neural networks can be trained to analyze images by looking...
An international research group led by scientists from the University of Bayreuth has produced a previously unknown material: Rhenium nitride pernitride. Thanks to combining properties that were previously considered incompatible, it looks set to become highly attractive for technological applications. Indeed, it is a super-hard metallic conductor that can withstand extremely high pressures like a diamond. A process now developed in Bayreuth opens up the possibility of producing rhenium nitride pernitride and other technologically interesting materials in sufficiently large quantity for their properties characterisation. The new findings are presented in "Nature Communications".
The possibility of finding a compound that was metallically conductive, super-hard, and ultra-incompressible was long considered unlikely in science. It was...
24.06.2019 | Event News
29.04.2019 | Event News
17.04.2019 | Event News
19.07.2019 | Physics and Astronomy
19.07.2019 | Physics and Astronomy
19.07.2019 | Earth Sciences