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Feb
15
Thu 8:45 AM

ChBE Seminar Series

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When: Thursday, February 15, 2018
8:45 AM - 10:00 AM  

Where: Technological Institute, L361, 2145 Sheridan Road, Evanston, IL 60208 map it

Audience: - Faculty/Staff - Student - Post Docs/Docs - Graduate Students

Contact: Cody Jarrett   847.467.4824

Group: McCormick-Chemical and Biological Engineering

Category: Academic

Description:

William Bothfeld, Tyo Lab:

Title
A glucose-sensing toggle switch for autonomous, high productivity genetic control

Abstract
Great progress has been made in expanding the number and types of chemicals made biologically. Many of the strategies to biosynthesize these chemicals involve production during cell growth. This scheme is inherently limited because feedstock (e.g., sugar) is converted to excess biomass instead of product, essential genes must be maintained for cell growth, and a high titer of product can be toxic to growth and may limit yields. A two-stage growth and production phase strategy could avoid these issues. At bench scale, chemical additions turn on production pathways in cells to implement two-phase strategies. However, these chemicals are expensive and not practical for large scale production. We have developed a genetic toggle switch that uses glucose sensing to enable this two-phase strategy. Temporary glucose starvation precisely and autonomously activates product expression in rich or minimal media, obviating the requirement for inducing chemicals. The switch remains stably in the new state even after reintroduction of glucose. In the context of polyhydroxybutyrate biosynthesis (a bio-polymer), our system enables shorter growth phases and comparable titers to cells that are steadily expressing PHB at near maximal tolerance levels. This two-phase production strategy, and specifically the glucose toggle switch, should be broadly useful to initiate many types of genetic program for metabolic engineering applications.

 

Robert Brydon, Broadbelt Lab:

Title
Microkinetic modeling of homogeneous and catalyzed oxidation systems

Abstract
Epoxidation, a specific form of partial oxidation, is an especially valuable process for the production of resins, plasticizers, curing agents, and more products. Traditional mechanisms used to explain partial oxidation systems are often insufficient when applied to cases where there is a high selectivity to epoxide products. This work sought to create a comprehensive microkinetic model that could be applied to a variety of partial oxidation systems with varying intrinsic selectivities to epoxide products. A challenge in modeling is the ability to sufficiently capture the behavior of complex chemistry without the scale of the model becoming unreasonable. By employing automatic network generation with a reaction family approach, a set of reactions and parameters of manageable size was created for partial oxidation and validated against experimental data. The resultant net flux analysis provided insights that shape a new understanding of epoxidation through radical intermediates. With the contribution of homogeneous oxidation well-defined, the developed microkinetic model was adapted to account for various catalysts. The resultant models were then used to investigate the effect of catalysts, including gold nanoparticles and transition metal oxides, on oxidation activity and selectivity.

 

Feb
22
Thu 8:45 AM

ChBE Seminar Series, Dr. Jeffrey J. Richards

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When: Thursday, February 22, 2018
8:45 AM - 10:00 AM  

Where: Technological Institute, L361, 2145 Sheridan Road, Evanston, IL 60208 map it

Audience: - Faculty/Staff - Student - Post Docs/Docs - Graduate Students

Contact: Cody Jarrett   847.467.4824

Group: McCormick-Chemical and Biological Engineering

Category: Academic

Description:

Jeffrey J. Richards

Title:
Colloidal Fluids as Electrical Current Collectors

Advances in synthetic techniques have enabled a revolution in the design of colloidal dispersions that contain particles with an enormous variety of sizes, shapes and compositions. These advances have not only provided access to a sophisticated understanding of intimate link between a dispersion’s microstructure and its macroscopic properties, but also form the basis of a powerful design paradigm to formulate advanced colloidal materials to address a wide range of important societal problems.


In this talk, I will highlight our recent progress toward understanding the intrinsic link between the electrical conductivity and the rheological properties of suspensions of electrochemically active nanoparticles. Such suspensions increasingly comprise the working fluid in electrochemical flow applications. In this context, a key design constraint collector is the trade-off between electrical performance and viscosity. To examine the origin of these macroscopic properties, we formulated suspensions of two, high-structured carbon blacks in neat propylene carbonate and characterize their rheological and electrical properties using small amplitude oscillatory shear and impedance spectroscopy at concentrations spanning the fluid-gel transition. Using these methods, we identify the electrical and mechanical percolation transitions and rationalize these results in the context of the equilibrium microstructure determined from scattering measurements. These results coupled with emerging in situ characterization techniques reveal a pathway toward current collectors with improved performance.

 

Bio:
Jeffrey J. Richards received his PhD in August 2014 from the Department of Chemical Engineering at the University of Washington working for Dr. Lilo D. Pozzo. During that time, he was an NSF IGERT Fellow and the College of Engineering Dean’s Fellow. After graduating from UW, he had the opportunity to join Dr. Norman Wagner’s group at the University of Delaware as a postdoctoral scholar in the Department of Biomolecular and Chemical Engineering Department before starting his NRC Fellowship at the NIST Center for Neutron Research in Gaithersburg, MD. Jeffrey’s current research focus at the NCNR is the development of in situ characterization techniques for electrochemically active colloidal systems.

 

 

Mar
1
Thu 8:45 AM

ChBE Seminar Series, Dr. Amanda Marciel

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When: Thursday, March 1, 2018
8:45 AM - 10:00 AM  

Where: Technological Institute, L361, 2145 Sheridan Road, Evanston, IL 60208 map it

Audience: - Faculty/Staff - Student - Post Docs/Docs - Graduate Students

Contact: Cody Jarrett   847.467.4824

Group: McCormick-Chemical and Biological Engineering

Category: Academic

Description:

Amanda Marciel

Title:
Structure and Rheology of Polyelectrolyte Complex Coacervates

Polyelectrolyte complexes are highly tunable materials that span from low-viscosity liquids (coacervates) to high-modulus solids with high water content, making them attractive as surface coating, membrane purification and bioadhesive materials. However, most of their properties and their effects with salt, pH, polymer ratio and temperature have only been qualitatively described. Here, we present a scattering investigation of the structure and chain conformations, and rheological properties of polyelectrolyte complex (PEC) coacervates comprising model polyelectrolytes. Systematic studies using small-angle X-ray scattering (SAXS) of the structure and chain behavior in liquid PEC coacervates revealed a physical description of these materials as strongly screened semidilute solutions of polyelectrolytes comprising oppositely charged chains. At the same time, solid PECs were found to be composed of hydrogen-bonding driven stiff ladder-like structures with large correlation lengths. While the liquid complexes behaved akin to semidilute polyelectrolyte solutions upon addition of salt, the solids were largely unaffected by it. Terminal relaxations of the chains in PEC coacervates were explored by rheology measurements. Excellent superposition of the dynamic moduli data was achieved by a time-salt superposition, although with the shift factors varying more strongly than previously reported with increasing salt concentration.

Bio:

Amanda Marciel is currently a postdoctoral fellow at the Institute for Molecular Engineering (IME) at The University of Chicago working with Professor Matthew Tirrell studying the physical properties of polyelectrolyte complexes. In 2015, Amanda completed her PhD with Professor Charles Schroeder at the University of Illinois at Urbana-Champaign where she developed a synthetic platform to precisely control polymer microstructure and implemented a microfluidic strategy to drive assembly of complex polymer architectures for biomedical and electronics applications.

 

Mar
8
Thu 8:45 AM

ChBE Seminar Series

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When: Thursday, March 8, 2018
8:45 AM - 10:00 AM  

Where: Technological Institute, L361, 2145 Sheridan Road, Evanston, IL 60208 map it

Audience: - Faculty/Staff - Student - Post Docs/Docs - Graduate Students

Contact: Cody Jarrett   847.467.4824

Group: McCormick-Chemical and Biological Engineering

Category: Academic

Description:

TBA

Title:
TBA

 

Bio:
TBA

 

 

Mar
15
Thu 8:45 AM

ChBE Seminar Series

SHOW DETAILS

When: Thursday, March 15, 2018
8:45 AM - 10:00 AM  

Where: Technological Institute, L361, 2145 Sheridan Road, Evanston, IL 60208 map it

Audience: - Faculty/Staff - Student - Post Docs/Docs - Graduate Students

Contact: Cody Jarrett   847.467.4824

Group: McCormick-Chemical and Biological Engineering

Category: Academic

Description:

TBA

Title:
TBA

 

Bio:
TBA