Biomass Formation and Modification
Biomass Deconstruction and Conversion
Natural Biocatalysts Outperform Industry Standard
Comparative study finds heat-loving microbes could reduce the need for thermochemical pretreatment
In the most comprehensive controlled comparison to date of lignocellulosic solubilization by various biocatalysts, BESC researchers found that naturally cellulolytic microbes such as Clostridium thermocellum (stained green and growing on poplar tissue in image) achieved significantly higher solubilization yields over commercial pretreatment systems. [Image courtesy ORNL]Read More
Promise of Unusual Lignin Polymer as Feedstock for Carbon Fiber
Stronger, Lighter Carbon Fiber Could Be Used in Parts for Cars, Aircraft, Electronics, and Sports Equipment
BESC researchers discovered an unusual lignin polymer in the seed coats of vanilla beans (pictured) that is naturally biosynthesized from caffeyl (C) alcohol. In contrast to lignin polymers that are highly cross-linked, C-lignin is a linear polymer, which makes it easier to process into high-quality carbon fibers. [Image courtesy iStock]Read More
Identification of Poplar Adaptation Mechanisms
Findings Could Lead to More Efficient Ways of Breeding High-Ethanol-Yielding Poplar and Other Tree Species
Using whole-genome sequencing and high-throughput phenotyping, BESC researchers were able to rapidly pinpoint gene mutations responsible for causing low lignin levels in poplar trees planted in a variety of environmental conditions. This proof-of-concept will allow researchers to tag genes associated with other economically important but complex plant traits. [Image courtesy BESC]Read More
Beneficial Plant Gene Discovery
Research Lays Groundwork for New Ways of Manipulating Plants
BESC researchers discovered a previously uncharacterized gene (GXMT1), which directs a key step in the development of xylan, a principal component of cell walls in plants such as Arabidopsis (pictured). Characterizing this gene, which makes the plant resistant to biofuel conversion, will lead to improved strategies for modifying such cell wall structures to help turn plants into biofuel more efficiently. [Image courtesy iStock]Read More
Molecular Structure of Plant Biomass
Imaging Reveals Enzymes in Action and Significance of Plants' Nanoscale Architecture
Plant cell walls contain networks of cellulose microfibrils that can be broken down into sugars for fuel and complex polymers that shield the cellulose from enzymatic attack. To characterize cell wall structure at the subnanometer scale and assess its response to chemical pretreatment, BESC developed techniques to image enzyme digestion in real time, revealing that biomass reactivity is determined by the nanoscale architecture of plant cell walls.Read More
A Leap Forward in Microbial Ethanol Yields
Engineered yeast converts up to 97% of plant sugars into fuel
Scientists at BESC and research partner Mascoma LLC have developed an advanced strain of Saccharomyces cerevisiae that sets a new standard for conversion of biomass sugars from pretreated corn stover. While conventional yeast (pictured) leaves more than one-third of plant sugars unused in the form of xylose, the C5 FUEL™ microbe efficiently converts this xylose into ethanol in less than 48 hours.Read More
Real-World Performance of Low-Lignin Switchgrass
Field study assesses sugar release and ethanol yield in transgenic feedstock
Lignin in the cell walls of switchgrass and other bioenergy feedstocks severely limits the accessibility of cell wall carbohydrates to enzymatic breakdown into fermentable sugars and subsequently biofuels. In the first reported study of its kind, the biofuel potential of transgenic switchgrass with reduced lignin content was evaluated over two growing seasons.Read More
Using a "commercialization council" of technology transfer and intellectual property (IP) management professionals from partner institutions, BESC evaluates the commercial potential of new inventions arising from BESC research and promotes and facilitates the licensing of BESC IP.
BESC's education program, which is 75% self-sustaining, takes a novel approach. BESC has developed lesson plans to educate students about energy production and utilization. BESC uses a hub-and-spoke approach of working through regional science centers to maximize hands-on access and adaptation to local conditions.
Progress to Date
NREL Researchers Discover how a bacterium, clostridium thermocellum, utilizes both CO2 and Celluloase to make Biofuels
Why Science? - with Kyle Sander
The Poplar Genome at 10
Creative Discovery Museum receives the Center for Interactive Learning and Collaboration Pinnacle Award
November 29, 2016
New Approach Allows Resolution Of Xylan Polymers In Plant Cell Wall
This approach demonstrated that xylan, an important plant polymer source, can be resolved from cellulose and lignin in situ using enzymatic digestion and label-free SRS microscopy. This can be used to enhance understanding of xylan in cell wall biosynthesis and deconstruction.
November 21, 2016
Mini Review Surveys Improvements In Understanding Relationship Of Lignin Structure To Biomass Recalcitrance
This review focuses on advances in understanding the specific roles of lignin properties during pre-treatment; lignin-enzyme interactions; monolignol compositional units; and hydroxycinnamates and hydroxyl and carboxylic groups in lignin.
November 03, 2016
Comparisons of five transgenic switchgrass lines to their parental controls (* indicates not a stati (...more)
Comparative Analysis Of Field-Grown Transgenic Switchgrass Lines Shows Stable Increases In Biofuel Yields
Clones of plants representing independent transgenic events and their respective non-transgenic control lines were investigated for biomass yield, carbohydrate composition, and recalcitrance to bioconversion via separate hydrolysis and fermentation to ethanol. Over two consecutive field-growth seasons, most transgenic lines maintain higher glucan and xylan yield at similar, or sometimes better, plant biomass. Transgenic lines targeting cell wall modifications yielded significantly higher bioconversion to ethanol (up to 36% and 21% in year 1 and year 2, respectively).
November 02, 2016
Mean soil organic matter in the upper 0-15 cm (A) and deeper 15-30 cm (B) during the first two growi (...more)
Field Grown Transgenic Switchgrass Has No Negative Affect On Soil Chemistry, Microbiology Or Carbon Storage Potential
BESC has demonstrated that when shoot S/G lignin ratio is decreased in switchgrass, greater yields of biofuel can be produced; understanding agronomic consequences of such changes is important to proving industrial value of engineered biofuel crops. COMT-altered switchgrass appears to be substantially equivalent to non-engineered switchgrass with regards to soil and microbiome properties.
November 01, 2016
Heat map of C. thermocellum transcriptomic response to exogenous acetate. Blue and yellow ind (...more)
Improving Robustness of Engineered C. thermocellum
Understanding and overcoming low robustness in engineered microorganisms will be essential to industrial deployment of these organisms. This study helps reveal mechanisms of electron balancing in C. thermocellum that leads to increased robustness in its potential use in biofuel production.
October 28, 2016
Schematic of reductive C1 metabolism initiated from reversed PFOR and PFL. Carbons in red indicate < (...more)
C. thermocellum Endowed with Ability to Fix CO2
A novel route that C. thermocellum employs to fix CO2 when grown in primarily heterotrophic mode supplemented with sodium bicarbonate was discovered. Critical enzymes responsible for fixing CO2 and channeling the fixed carbon to the C1 metabolic pathway were identified. This research paves the way to future engineering of the Clostridium thermocellum bacterium to utilize cellulose and CO2 simultaneously as a means to improve microbial carbon efficiency and reduce CO2 in the environment.
October 19, 2016
National Bioenergy Day
BESC participated with seven different agencies to provide educational and informative biofuel connected activities and displays for ~200 elementary children during the National Bioenergy Day celebration held at the University of Tennessee (UT) Arboretum in Oak Ridge, Tennessee.
September 30, 2016
GreenWood and ORNL Sign Agreement.
Seated: Brian Stanton, Chief Science Officer, GreenWood Resour (...more)
GreenWood Resources Licenses BESC Invention to Boost Biofuel Yield
GreenWood Resources has licensed a BESC technology based on the discovery of a gene in Populus trichocarpa that makes it easier to convert poplar trees into biofuels. They plan to commercialize the technology to select and breed better varieties of poplar with less lignin content, which simplifies the conversion process and ultimately lowers the overall costs of biofuel production.
September 15, 2016
New Thioacidolysis Method Allows for Improved Throughput in Linking Biomass Recalcitrance with Lignin Structure and Composition
Thioacidolysis is a method used to measure the relative content of coumaryl (H), syringyl (S) and coniferyl (G) alcohol lignin monomers bound by β-O-4 linkages. This new method was developed with significantly higher throughput than traditional techniques and was found to measure statistically similar S/G ratios in lignin from different lignocellulosic biomass types relative to a traditional low-throughput technique. The composition and structure of lignin based on the relative amount of monomers bound by β-O-4 linkages can be more rapidly determined for screening purposes allowing for improved throughput in linking biomass recalcitrance with lignin structure and composition.
September 06, 2016
Development Of A Genome-Scale Metabolic Model Of C. Thermocellum Assists In Strain Design For Biofuels And Chemicals
Genome scale modeling is a powerful tool for investigating cellular metabolism. A genome scale model (GEM) of DSM 1313 was constructed and curated for simulation of growth on alternative cellulosic substrates by implementing an adjustable cellulosome. Using the GEM, researchers were able to explore how key redox and bioenergetic reactions change as a function of growth rates and carbon sources in a systematic manner. Use of the model led to a proposed substrate-dependent regulatory mechanism by which ethanol production is enhanced or limited.
August 25, 2016
Heterologous Expression of Xylanases from A. cellulolyticus Enhances Hemicellulolytic Activity of C. bescii
To test whether the addition of A. cellulolyticus xylanases might enhance the hemicellulolytic activity of C. bescii and growth on xylan substrates, the xylanases were expressed in C. bescii using new expression vectors. Expression of the xylanases in C. bescii results in an increase in the activity of the exoproteome on xylan and a dramatic increase in its ability to grow on xylan substrates.
August 10, 2016
Microbial Upgrading of Lignin-Derived Carboxylates to Branched-Chain Esters for Drop-in Biofuels
An innovative biological conversion route was developed for conversion of lignocellulosic biomass or organic wastes into biofuels and high-value chemicals.
August 08, 2016
HPC Simulation of Co-Solvent Pretreatment of Biomass Confirmed by Experiment
Previous BESC work has shown that reaction of biomass in aqueous tetrahydrofuran (THF) in CELF (Co-solvent Enhanced Lignocellulosic Fractionation) pretreatment is highly effective at delignification and deconstruction of biomass for biofuels and bioproducts. Molecular dynamics simulations were performed of whole cellulose fibers and single cellulose chains in a THF-water co-solvent at various temperatures on the ORNL TITAN supercomputer. The simulations were complemented by THF-water experiments on cellulose, measuring its solubilization and imaging the product residue.
August 05, 2016
Creative Discovery Museum Receives Pinnacle Award for Distance Learning
The Creative Discovery Museum (CDM) has been awarded a Center for Interactive Learning and Collaboration (CILC) Pinnacle Award for 2015 – 2016 based on recipient evaluations. The BESC-sponsored CDM "Distance Learning Biofuels" program is a 50-minute lesson designed for students in grades 4 – 8. A museum educator from CDM provides the lesson via video conferencing. The program provides the opportunity for students to learn about innovative research taking place in the fields of biofuels and alternative energy.
July 27, 2016
One-hour hydrolysis rate versus cumulative cellulose conversion for uninterrupted and restarted hydr (...more)
Cellulose DP And Accessibility Contribute To Cellulase Enzyme Action On Biomass Substrate
The enzymatic hydrolysis of lignocellulosic biomass proceeds initially at a fast rate followed by a rapid decrease in the conversion rates. Degree of polymerization (DP) analysis during hydrolysis suggested a synergistic action of endo- and exo-glucanases that contribute to the occurrence of a peeling off mechanism. Cellulose accessibility analysis showed that limited accessible surface area of cellulose is probably not a major limiting factor that causes the decline of hydrolysis rate in its late stage. Restart hydrolysis experiment suggested that enzyme related factors such as enzyme inactivation or steric hindrance of enzymes should be responsible to the reduction in hydrolysis rate given the large size of cellulase enzymes.
June 21, 2016
James Liao Appointed To Serve As Academia Sinica President
Dr. James Liao has been named as the 11th president of Academia Sinica — the top academic research institution in Taiwan. Academia Sinica supports research activities in a wide variety of disciplines, ranging from mathematical and physical sciences, to life sciences and to humanities and social sciences. Dr. Liao serves as the BESC Activity Lead for Butanol Production by CBP.
June 20, 2016
Discovery Of A Novel Molecular Mechanism Controlling Seed Physical Dormancy
Physical seed dormancy exists widely in higher plants, but its molecular mechanism has remained largely elusive. By screening a large number of Tnt1 retrotransposon-tagged Medicago truncatula lines, we identified non-dormant seed mutants from this model legume species. This study elucidated a novel molecular mechanism of physical dormancy and revealed a new role of class II KNOX genes.
June 20, 2016
Improved Thermophilic Anaerobe Achieves High Biofuel Titers From Wood And Cellulose
This study demonstrates that thermophilic anaerobes are capable of producing ethanol at high yield and at titers greater than 60 g/L from purified substrates. However,challenges were encountered with existing fungal cellulases and inhibitors from pretreatment. The high titers and yields observed support the feasibility of using engineered thermophiles for industrial ethanol production if challenges associated with pretreatment inhibitors can be avoided.
June 20, 2016
Syringyl/Guaiacyl (S/G) Ratio In Lignin May Influence Quality Of Carbon Fiber Produced From Lignins
Current lignin-based carbon fiber using low-cost lignin precursors does not possess the mechanical properties required for many structural applications. Lignins with various syringyl/guaiacyl (S/G) ratios were isolated from Populus genotypes and subjected to rheological treatment at various temperatures and cooling conditions. Organosolv lignins extracted from genotypes with lower S/G ratios exhibited higher viscosity values and molecular weights with larger amounts of condensed structures following rheology treatment at relatively lower temperature; higher viscosity and molecular weight is known to provide for higher quality carbon fiber.
June 07, 2016
Simultaneous Achievement Of High Ethanol Yield And Titer In Clostridium thermocellum
Adaptive evolution successfully improved the ethanol yield and the titer from a rationally engineered CBP strain. This evolved strain has the highest ethanol yield and titer reported to date for C. thermocellum, and is an important step in the development of this microbe for industrial applications.
June 01, 2016
Workshop Summary: Lessons From Industry In Commercializing Biotechnology
This article summarizes lessons learned drawn from the "Technology Challenges and Opportunities in Commercializing Industrial Biotechnology Workshop," September 28-29, 2015, San Diego.
May 09, 2016
A Bifunctional Ammonia-Lyase Is Critical In Grass Cell Wall Biosynthesis Of Lignin
Using phylogenetic, transcriptomic and in vitro biochemical analyses, a single homotetrameric cytosolic bifunctional ammonia-lyase (PTAL) was identified among eight BdPAL enzymes in the model grass species Brachypodium distachyon. 13C stable isotopic labelling experiments along with BdPTAL1-down-regulation in transgenic plants showed that the TAL activity of BdPTAL1 can provide nearly half of the total lignin deposited in grasses, with a significant preference for S-lignin and wall-bound coumarate biosynthesis.
April 29, 2016
Improved Whole Cell Wall NMR Measures Carbohydrate And Lignin Structures Without Derivatization
A new NMR solvent system composed of dimethylsulfoxide (DMSO-d6) and hexamethylphosphoramide (HMPA-d18) was developed to understand plant cell wall structures with minimal deconstruction and modification of biomass. The proposed bi-solvent system does not require derivatization or chemical modification, thus it facilitates easier sample preparation and less signal overlapping of correlation peaks compared to the traditional methods.
April 28, 2016
Identification And Overexpression Of Knotted1-Like Transcription Factor For Lignocellulosic Feedstock Improvement
Using transgenic approach, a switchgrass Knotted1 transcription factor, PvKN1 was overexpressed in switchgrass and transgenic plants were characterized for recalcitrance and growth-related traits. PvKN1 overexpression resulted in reduced lignin deposition/biomass recalcitrance and improved sugar release efficiency without affecting various growth parameters such as tiller height, tiller number, fresh and dry biomass.
April 28, 2016
Intellectual Property Impact of the BRCs
The Bioenergy Science Centers (BRCs) have generated over 500 invention disclosures, 328 patent applications (of which 45 have been awarded) which have led to 133 licenses or options with industry.
April 26, 2016
Development Of Improved Expression Plasmid In Clostridium thermocellum
Clostridium thermocellum is a promising candidate for ethanol production from cellulose biomass yet requires metabolic engineering to further improve ethanol yield. An expression plasmid was redesigned to improve transformation efficiency and structural stability. The new expression plasmid had both significantly higher transformation efficiency than its predecessor (~2x more), and was also able to more robustly express genes of interest.
April 26, 2016
New Genetic Markers Identified For Switchgrass Cell Wall Composition And Conversion
A full-sib switchgrass population was developed by crossing a lowland genotype (AP13) to an upland genotype (VS16). QTL associated with the traits of interest were identified. Significant variation for glucose, xylose and total sugar release, and lignin content (19-27%) in the population; a unit increase in lignin content reduced total sugar release by an average of 10 mg g-1; and QTL analysis detected nine genomic regions underlying sugar release and 14 for lignin content.
April 26, 2016
Structural Diversity Of Xylans Measured In Cell Walls Of Monocots
This study provides a new perspective on the diversity, function and evolution of monocot cell walls, enabling the manipulation of xylan structure and development of new technologies for the conversion of biomass from this important family of plants to yield commercially valuable and sustainable products.
April 25, 2016
BRCs Well Represented at Symposium on Biotechnology for Fuels and Chemicals
The Symposium on Biotechnology for Fuels and Chemicals (SBFC) was held April 25-28, 2016, in Baltimore, Maryland. As part of the overall symposium the combined Bioenergy Research Centers (BRCs) presented thirty-seven talks and twenty posters representing 25% of the talks and 10% of the posters.
April 18, 2016
Lignification And Recalcitrance Affected By Age And Season In Field-Grown COMT-Downregulated Switchgrass
Previous field and greenhouse studies have shown that COMT-downregulation in switchgrass decreases lignin content and reduces the S/G ratio, thereby lowering recalcitrance and improving ethanol yields. Trends in lignification and recalcitrance differ between growing seasons. Third-year results showed an increase in lignification and decrease in sugar release across the season. S/G ratios increased over time in non-transgenic control lines, but were relatively stable in COMT-downregulated lines. During early (elongation) growth stages, cell wall chemistry was similar between COMT-downregulated and control lines. After reaching the reproductive growth stage in July, COMT-downregulated lines maintained reduced lignin content, decreased S/G ratios, and improved sugar release through December. No differences in rust susceptibility were observed.