Highlights Archive

Search Highlights:

November 21, 2011

A fundamental discovery by University of Georgia scientists Melani Atmodjo (left) and Debra Mohnen ( (...more)

The University of Georgia (UGA) discovery changes the way scientists think about how plant cell walls are made and holds implications for biofuels
Wood and grasses, sources of lignocellulosic biomass, are enriched in the tough secondary wall – this new discovery provides a means for modifying pectin to improve the availability of carbon reserves in the plant cell wall for renewable sources of energy.

October 20, 2011

BESC investigates tension wood formation as a model for studies of reduced recalcitrance
Tension wood is formed in response to tension stress on upper side of bent stems and is characterized by many desirable feedstock properties. BESC researchers undertook a first-of-its-kind study of tension wood formation in Populus integrating phenotyping techniques such as CARS, 13C CP/MAS, py-MBMS and GPC and correlating results to recalcitrance assays. Tension wood samples were found to contain higher cellulose and lower lignin levels as well as increased % crystallinity, % total and accessible fibril surfaces, cell wall thickness and xylem cell number. Combinatorial effects of increased accessible specific surface area, localized lignin down-regulation and chemical alteration along with increased accumulation of cellulose was found to result in significantly increased enzymatic hydrolysis yields and reduced biomass recalcitrance. The present study in integration with molecular assessments is yielding new gene targets for further evaluation in the design of suitably tailored bioenergy feedstocks.

October 10, 2011

BESC Website Renovation
The BESC website (bioenergycenter.org) recently underwent a renovation to facilitate a more user friendly interface which includes several new features to highlight the science of BESC. News - highlights of recent media exposure Publications – up to date front page information on current and recently published BESC publications Partners – expanded information on BESC inventions and industrial opportunities Who’s Who – pictorial comprehensive listing of BESC management, scientists, SAB and BOD members Research – expanded sections on Biomass Formation, Deconstruction & Conversion and Characterization & Modeling science areas Video – new video interviews of BESC scientists Featured Scientist – monthly feature section on a BESC scientist Newsletter – sign up capability for web users to receive the BESC newsletter electronically or to request information Expanded and revised navigation tools to aid web users in locating just the right information they may be seeking about BESC

September 11, 2011

Salicylic acid mediates the reduced growth phenotype of plants with strong reductions in lignin content
Blocking formation of SA by a genetic knock-out (sid2) restores growth to low lignin (HCT-RNAi) Arabidopsis plants while maintaining low lignin levels. Therefore, high SA rather than low lignin is the reason for the growth defects, indicating that it is possible to engineer plants with very low lignin and good biomass yield.

August 16, 2011

Single Microbial Gene Linked to Increased Ethanol Tolerance
A mutated alcohol dehydrogenase (AdhE) with altered co-factor specificity was shown to enhance ethanol tolerance in Clostridium thermocellum, a candidate consolidated bioprocessing microbe. The simplicity of the genetic basis for this ethanol-tolerant phenotype informs rational engineering of mutant microbial strains for cellulosic ethanol production.

July 18, 2011

2011 BESC Science Retreat
The BioEnergy Science Center held their 5th Annual Science Retreat in Chattanooga, Tennessee, on July 18th - 21st 2011. The retreat was attended by over 250 members of BESC, including researchers, post-docs, students, commercialization council members, industrial affiliates, science advisory board members and members of the board of directors.

July 12, 2011

Co-Hydrolysis of Pretreated Populus Slurries to Support Development of a High-Throughput Pretreatment System
The co-hydrolysis approach can be confidently applied in high-throughput systems to screen for low recalcitrant plants, optimize enzyme formulations, determine whether lower severity pretreatments can achieve high sugar yields, and facilitate identification of enzymes that withstand inhibitors from pretreatment.

June 14, 2011

Genetic Response during Cellulose Fermentation by Clostridium thermocellum Elucidated
Under limited carbon situations growth slows to decrease metabolic burden and C. thermocellum alters gene expression to modulate the composition of cellulosomes which are released into the environment.

June 11, 2011

BIO International Convention—BESC Highlights
At the annual biotechnology gathering, BESC met with Congressional staffers and federal agency representatives, as well as state and industry representatives, to brief them on the progress of research.

June 01, 2011

Representation of a cellulosome from C thermocellum: Scaffoldin (blue). Enzymes in gray.

Self-Assembly of the Cellulosome Enzyme Complex Shows Larger Sub-units Bind More Rapidly
This study can be used to produce designer cellulosomes with enhanced or decreased binding affinity for the scaffoldin to produce improved catalysts. Demonstrates that numerical modeling can be applied successfully to large, complex biological systems.

May 16, 2011

The mathematical model allowed the inference of metabolic channels as well as a significant regulatory mechanism controlling the pathway.

Mathematical Modeling Elucidates Control of Lignin Biosynthesis
BESC researchers developed a novel model combining static flux-based analysis with Monte Carlo simulation to identify control points in the lignin biosynthetic pathway. The model, built upon experimentally generated S/G monolignol data from stem internodes of transgenic alfalfa (Medicago sativa L.) lines, predicted new metabolic channels and novel regulatory control schemes which then were confirmed experimentally (e.g., salicylic acid).

May 16, 2011

Mathematical Modeling Elucidates Control of Lignin Biosynthesis
Ratios of lignin monomers can be a significant contributor to recalcitrance of biomass to cellulosic biofuel conversion. BESC researchers developed a novel model combining static flux-based analysis with Monte Carlo simulation to identify control points in the lignin biosynthetic pathway. The model, built upon experimentally generated S/G monolignol data from stem internodes of transgenic alfalfa (Medicago sativa L.) lines, predicted new metabolic channels and novel regulatory control schemes which then were confirmed experimentally (e.g., salicylic acid). Such wall biosynthesis pathway models are indispensable tools in the rational design of feedstock crops for efficient biofuels production.

May 02, 2011

BESC Well Represented at the Symposium on Biotechnology for Fuels and Chemicals—2011
BESC researchers presented 15 posters and 9 presentations at the Symposium.

May 01, 2011

BESC Compiles Biomass Characterization Technique Reference
This includes brief descriptions of the methods, sample preparation, and the contact person.

April 15, 2011

Quantitative Proteomics Reveal the Secreted, Highly Thermostable Cellulases of Two Extremely Thermophilic Bacteria
53-57 proteins changed in abundance during the course of cellulose fermentations, including glycosidases, pectate lyases and extracellular binding proteins. Caldicellulosiruptor spp. secrete a small number of highly abundant multidomain, multifunctional glycosidases with carbohydrate binding domains. Glycosidase mixtures efficiently degraded crystalline cellulose at 85°C. Glycosidase domains and architecture vary between the two closely related species.

April 01, 2011

Microbe engineered to produce isobutanol directly from cellulose
BESC researchers engineered a native cellulose-degrading microbe, Clostridium cellulolyticum, to produce isobutanol. Demonstrating the ability to combine CBP (consolidated bioprocessing) with production of next generation biofuels.

March 01, 2011

Lignin content and composition in natural Populus variants affects sugar release
The largest recalcitrance studies of Populus natural variants. Strong negative correlation between lignin content and glucose release does not apply to biomass samples with an S/G ratio > 2.0. Certain natural variants yielded unusually high sugar yields with no pretreatment. New insight for the rational design of biomass with reduced recalcitrance and efficient biofuels production.

March 01, 2011

Genetic manipulation of lignin improves biofuel production from switchgrass
Down-regulation of a single gene reduces recalcitrance with no apparent growth defects and leads to: Increase in ethanol production by over one third. Reduction in needed severity of pre-treatment. Evidence that biofuel processing costs can be reduced by at least 20% with 300-400% lower enzyme costs.

January 01, 2011

Snapshot of the 2 lignin-cellulose models at the end of the Molecular Dynamics simulations

Lignin Aggregation and Precipitation onto Cellulose: A Molecular Dynamics Study
Biomass recalcitrance after acid pretreatment: lignin aggregation and reprecipitation onto cellulose. Lignin Forms Larger Interface (closer affinity) with Crystalline Cellulose vs. Semi-Crystalline.

January 01, 2011

Complete Genome Sequence for Five Anaerobic, Extremely Thermophilic, Plant Biomass-Degrading Caldicellulosiruptor Species
Whole genome sequences (WGS) now available for eight geographically diverse species. Includes three hemicellulolytic but less cellulolytic species.

BioEnergy Science Center one of three DOE Bioenergy Research Centers established by the U.S. Department of Energy.