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Research Interests

I have broad research interests in fluid mechanics, rheology, separation science, reaction engineering, mathematical modeling, and scientific computing. At the National Renewable Energy Laboratory (NREL) I am applying expertise in these areas to the biochemical conversion of lignocellulosic biomass to renewable fuels, chemicals, and materials.

During low-temperature conversion processes, ground biomass feedstock is degraded by chemical and biological catalysts in the presence of water to become a liquid slurry. The reacting biomass slurry is a heterogeneous, multiphase material with complex physical and chemical properties. Well-established Newtonian fluid mechanics and solution reaction kinetics do not apply to these biomass slurries. We are performing fundamental and applied research to understand the fluid mechanics, mass transfer, and reaction kinetics of the biomass slurries in order to develop predictive modeling capabilities. Developed models and computational simulations are then used to guide the improvements in overall conversion efficiency and process economics.

We are also investigating routes to process intensification by integrating separation with reaction. Specifically, we have developed a process for continuous enzymatic hydrolysis in which membrane separation is used to continuously remove sugars from the system, thereby lowering product inhibition of the enzymes and improving volumetric productivity.

Reliable storage and transport of milled lignocellulosic feedstocks during preprocessing steps has proven to be a huge challenge in pilot- and demonstration-scale biorefineries. In collaboration with other national laboratory and corporate partners, we are working to develop an improved physical understanding of the mechanics of granular flow and to develop computational models suitable for simulating the flow of milled biomass feedstocks.


  • Ph.D., Chemical Engineering, University of California at Davis, 2006

  • B.S., Chemical Engineering, Rensselaer Polytechnic Institute, 1999

Professional Experience

  • Senior Research Engineer, NREL, Golden, CO, 2009–present

  • Research Engineer, NREL, Golden, CO, 20072009

  • Process Development Engineer, Bayer Healthcare, Berkeley, CA, 20052007

  • Graduate Student Researcher, University of California, Davis, CA, 20012005

  • Process Engineering Associate, Biogen Idec (Biogen, Inc.), Cambridge, MA, 19992001

Featured Publications

  1. "Continuous enzymatic hydrolysis of lignocellulosic biomass in a membrane-reactor system," Journal of Chemical Technology & Biotechnology (2018)

  2. "Formulation and validation of a computational model for a dilute biomass slurry undergoing rotational mixing," Chemical Engineering Science (2018)

  3. "Modeling residence-time distribution in horizontal screw hydrolysis reactors," Chemical Engineering Science (2018)

  4. "Demonstration of parallel algal processing: production of renewable diesel blendstock and a high-value chemical intermediate," Green Chemistry (2018)

  5. "Technical Performance and Economic Evaluation of Evaporative and Membrane-Based Concentration for Biomass-Derived Sugars," Industrial & Engineering Chemistry Research (2017)

  6. "Online residence time distribution measurement of thermochemical biomass pretreatment reactors,"  Chemical Engineering Science (2016)

  7. "Mixing behavior of a model cellulosic biomass slurry during settling and resuspension," Chemical Engineering Science (2016)

  8. "The effects of physical and chemical preprocessing on the flowability of corn stover," Biomass and Bioenergy (2016)

  9. "Two-stage dilute-acid and organic-solvent lignocellulosic pretreatment for enhanced bioprocessing,"  Bioresource Technology (2016)

  10. "Multiphysics modeling and simulation of high-solids dilute-acid pretreatment of corn stover," Chemical Engineering Journal (2015)

  11. "A low-cost solid–liquid separation process for enzymatically hydrolyzed corn stover slurries,"  Bioresource Technology (2015)

  12. "Parameter determination and validation for a mechanistic model of the enzymatic saccharification of cellulose-Iβ," Biotechnology Progress (2015)

  13. "Investigation of a submerged membrane reactor for continuous biomass hydrolysis," Food and Bioproducts Processing (2015)

  14. "Sugar concentration and detoxification of clarified biomass hydrolysate by nanofiltration," Separation and Purification Technology (2014)

  15. "Connecting large amplitude oscillatory shear rheology to steady simple shear rheology and applications to biomass slurries," Applied Rheology (2014)

  16. "Enzymatic hydrolysis of lignocellulosic biomass," Bioprocessing of Renewable Resources to Commodity Bioproducts (2014)

  17. "Benchtop methods for measuring the fraction of free liquid of biomass slurries," Cellulose (2014)

  18. "Response of elastoviscoplastic materials to large amplitude oscillatory shear flow in the parallel-plate and cylindrical-Couette geometries,"  Journal of Rheology (2013)

  19. "A mechanistic model for enzymatic saccharification of cellulose using continuous distribution kinetics II: Cooperative enzymatic action, solution kinetics, and inhibition," Biotechnology and Bioengineering (2011)

  20. "A mechanistic model for enzymatic saccharification of cellulose using continuous distribution kinetics I: Depolymerization by EGI and CBHI," Biotechnology and Bioengineering (2011)

  21. "Mathematical modeling of chain-end scission using continuous distribution kinetics," Chemical Engineering Science (2011)

  22. "Particle morphology characterization and manipulation in biomass slurries and the effect on rheological properties and enzymatic conversion," Biotechnology Progress (2011)

  23. "Calculating sugar yields in high solids hydrolysis of biomass," Bioresource Technology (2011)

  24. "A Simplified Method for the Measurement of Insoluble Solids in Pretreated Biomass Slurries," Applied Biochemistry and Biotechnology (2010)

  25. "Data Smoothing and Numerical Differentiation by a Regularization Method," Computers and Chemical Engineering (2010)

  26. "Laboratory-Scale Method for Enzymatic Saccharification of Lignocellulosic Biomass at High-Solids Loadings," Biotechnology for Biofuels (2009)

  27. "Particle Concentration and Yield Stress of Biomass Slurries during Enzymatic Hydrolysis at High-Solids Loadings," Biotechnology and Bioengineering (2009)

  28. "Rheology Measurements of a Biomass Slurry: An Inter-Laboratory Study," Rheologica Acta (2009)

  29. "Application of a Constitutive Model for Particulate Suspensions: Time-Dependent Viscometric Flows,"  Journal of Rheology (2007)

  30. "A Constitutive Model for Microstructure and Total Stress in Particulate Suspensions,"  Journal of Rheology (2006)

  31. "Fluid Mechanics and Rheology of Dense Suspensions," Annual Review of Fluid Mechanics (2005)

  32. "Pressure-Flow Relationships for Packed Beds of Compressible Chromatography Media at Laboratory and Production Scale," Biotechnology Progress (2001)

  33. "Fractionation of multiwalled carbon nanotubes by cascade membrane microfiltration,"  Journal of Physical Chemistry B (1999)

View all NREL Publications for Jonathan J. Stickel.