Research Interests

Cellulase engineering and synergy for biomass conversion

Lab automation and high-throughput screening

Fungal molecular biology and fermentation

Non-dilute acid pretreatment technologies

Cellulose nanocrystal applications

Affiliated Research Programs

Enzyme Engineering and Optimization (PI)

BioEnergy Science Center – Biomass Recalcitrance (project lead)

BioEnergy Science Center – Enzymatic Fundamentals (contributor)


Targeted Microbial Deconstruction (contributor)

Cellulosic Nanocrystals (contributor)

Biological and Catalytic Conversion of Sugars and Lignin (collaborator)

Computational Modeling (collaborator)

Areas of Expertise

Protein biochemistry (enzyme assays and kinetics; protein engineering; protein expression and purification, including fungal/yeast/bacterial; fungal transformation; enzyme synergy/optimization for hydrolysis of biomass; cellulase biochemistry; and protein production through fermentation up to 100L scale)

Biomass conversion (functional understanding of multiple biomass pretreatment strategies, including acid/alkaline/neutral; detailed knowledge of biomass-hydrolyzing enzyme function and interaction with biomass feedstocks; and experience with numerous feedstock types)

Project and personnel management (coordinate scientists and engineers with diverse backgrounds to solve complex problems; plan budgets and annual operating plans; develop productive and cooperative relationships with internal and external—including international—partners; plan and meet milestones; obtain funding through various granting agencies and partners; and recurring Program Chair/Co-Chair for the annual Symposium on Biotechnology for Fuels and Chemicals of ˜700 attendees)

Unique problem-solving abilities (innovative and successful approaches to high throughput screening in biomass recalcitrance; development of a robust Trichoderma reesei expression system for Cel7 and other proteins; and direct and systematic solving of research roadblocks through logic and out-of-the-box thinking)


Ph.D., Microbiology, Colorado State University

M.S., Microbiology, University of Wisconsin, Oshkosh

B.S., Biology, University of Wisconsin, Stevens Point

Professional Experience

Principal Scientist/Section Supervisor, NREL, Project Leader in BioEnergy, Science Center, Subtask Leader for Advanced Biological Deconstruction (2013–present)

Senior Scientist II, NREL, Subtask Leader for Oligomer Saccharification, Task Leader for Joint U.S. Department of Energy/U.S. Department of Agriculture Project Edenspace Cooperative Research and Development Agreement (2007–2013)

Senior Scientist, NREL, Subtask Leader for Hemicellulase and Accessory Enzymes (2002–2006)

Staff Scientist II, NREL (1999–2002)

Postdoctoral Research Fellow, NREL (1996–1999)

Adjunct Faculty, Red Rocks Community College (2000–2004)

Featured Work

Working Towards Recalcitrance Mechanisms: Increased Xylan and Homogalacturonan Production by Overexpression of GAlactUronosylTransferase12 (GAUT12) Causes Increased Recalcitrance and Decreased Growth in Populus, Biotechnology for Biofuels (2017)

Distinct Roles of N- and O-Glycans in Cellulase Activity and StabilityProceedings of the National Academy of Sciences (2017)

Lignocellulose Deconstruction in the Biosphere, Current Opinion in Chemical Biology (2017)

Anaerobic Microplate Assay for Direct Microbial Conversion of Switchgrass and Avicel Using Clostridium thermocellum, Biotechnology Letters (2017)

Undefined Cellulase Formulations Hinder Scientific Reproducibility, Biotechnology for Biofuels (2017)

Biomass Conversion, in Handbook of Industrial Chemistry and Biotechnology (2017)

Multifunctional Cellulolytic Enzymes Outperform Processive Fungal Cellulases for Coproduction of Nanocellulose and Biofuels, ACS Nano (2017)

A Versatile 2A Peptide-Based Bicistronic Protein Expressing Platform for the Industrial Cellulase Producing Fungus, Trichoderma reesei, Biotechnology for Biofuels (2017)

Study of Traits and Recalcitrance Reduction of Field-Grown COMT Down-Regulated Switchgrass, Biotechnology for Biofuels (2017)

Downregulation of the UDP-Arabinomutase Gene in Switchgrass (Panicum virgatum L.) Results in Increased Cell Wall Lignin while Reducing Arabinose-Glycans, Frontiers in Plant Science (2016)

Biochemical and Structural Characterization of Two Dictyostelium Cellobiohydrolases from the Amoebozoa Kingdom Reveal a High Conservation between Distant Phylogenetic Trees of Life, Applied and Environmental Microbiology (2016)

Identification and Overexpression of a Knotted1-Like Transcription Factor in Switchgrass (Panicum virgatum L.) for Lignocellulosic Feedstock Improvement, Frontiers in Plant Science (2016)

Hybridization of Downregulated-COMT Transgenic Switchgrass Lines with Field-Selected Switchgrass for Improved Biomass Traits, Euphytica (2016)

New Perspective on Glycoside Hydrolase Binding to Lignin from Pretreated Corn Stover, Biotechnology for Biofuels (2015)

Down-Regulation of p-Coumaroyl Quinate/Shikimate 3′-Hydroxylase (C3′H) and Cinnamate 4-Hydroxylase (C4H) Genes in the Lignin Biosynthetic Pathway of Eucalyptus urophylla × E. grandis Leads to Improved Sugar Release, Biotechnology for Biofuels (2015)

High-Throughput Screening of Recalcitrance Variations in Lignocellulosic Biomass: Total Lignin, Lignin Monomers, and Enzymatic Sugar Release, Journal of Visualized Experiments (2015)

Identification and Molecular Characterization of the Switchgrass AP2/ERF Transcription Factor Superfamily, and Overexpression of PvERF001 for Improvement of Biomass Characteristics for Biofuel, Frontiers in Bioengineering and Biotechnology (2015)

A Constitutive Expression System for Glycosyl Hydrolase Family 7 Cellobiohydrolases in Hypocrea jecorinaBiotechnology for Biofuels (2015)

Rapid Estimation of Sugar Release from Winter Wheat Straw During Bioethanol Production Using FTIR-Photoacoustic Spectroscopy, Biotechnology for Biofuels (2015)

Field Evaluation of Transgenic Switchgrass Plants Overexpressing PvMYB4 for Reduced Biomass Recalcitrance, BioEnergy Research (2015)

Heterologous Protein Expression in Hypocrea jecorina: An Historical Perspective and New Developments, Biotechnology Advances (2015)

Identification and Characterization of Core Cellulolytic Enzymes from Talaromyces cellulolyticus (Formerly Acremonium cellulolyticus) Critical for Hydrolysis of Lignocellulosic Biomass, Biotechnology for Biofuels (2014)

Predicting Enzyme Adsorption to Lignin Films from Enzyme Surface Hydrophobicity, Journal of Biological Chemistry (2014)

Evaluation of High Throughput Screening Methods in Picking Up Differences between Cultivars of Lignocellulosic Biomass for Ethanol Production, Biomass and Bioenergy (2014)

Fungal Cellulases and Complexed Cellulosomal Enzymes Exhibit Synergistic Mechanisms in Cellulose Deconstruction, Energy & Environmental Science (2013)


Multi-Chamber Pretreatment Reactor for High Throughput Screening of Biomass, U. S. Patent Application 20100105570 (2010)

Processing Cellulosic Biomass, WIPO PCT Application PCT/US2009/048153, U. S. Patent Application 20120040408 (2009)

Cellobiohydrolase I Enzymes, U. S. Patent Application 20090162916 (2009)

Superactive Cellulase Formulation Using Cellobiohydrolase-1 from Penicillium funiculosum, U.S. Patent No. 8,283,150 (2012)

Superactive Cellulase Formulation Using Cellobiohydrolase-1 from Penicillium funiculosum, U.S. Patent No. 7,449,550 (2008)

Thermal Tolerant Exoglucanase from Acidothermus cellulolyticus, U.S. Patent No. 7393673 (2008)

Cellobiohydrolase I Gene and Improved Variants, U.S. Patent No. 7375197 (2008)

Thermal Tolerant Cellulase from Acidothermus cellulolyticus, U.S. Patent No. 7059993 (2006)

Alkaline Tolerant Dextranase from Streptomyces anulatus, U.S. Patent No. 6509184 (2003)

Cellulase Animation, U.S. Copyright Registration No. PAu-2-568-364 (2001)

Please contact me with research questions, ideas for collaborations, and questions about the Biomass Program and Recalcitrance Pipeline. Please do NOT contact me directly for jobs—see instead information on NREL's Director's Postdoctoral Fellowship program or on NREL Careers in general.