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Theses/Dissertations

Chemical engineering

Retrospective Theses and Dissertations

1994

Articles 1 - 6 of 6

Full-Text Articles in Engineering

Genetically Engineered Charge Modifications To Enhance Protein Separation In Aqueous Two-Phase Systems , John Richard Luther Jan 1994

Genetically Engineered Charge Modifications To Enhance Protein Separation In Aqueous Two-Phase Systems , John Richard Luther

Retrospective Theses and Dissertations

The purpose of this work was to investigate the effect of genetically engineered charge modifications on the separation behavior of proteins in aqueous two-phase extraction. The proteins used in this study included: [beta]-galactosidase, modified by the fusion of positively--or negatively--charged peptide tails to the carboxy terminus of the enzyme, and lysozyme, which has been altered by site-directed mutagenesis to replace basic amino acids with acidic ones. The effects of these charge modifications were evaluated in phase systems utilizing two different charge-based mechanisms;Protein net charge was found to be effective in systems where partitioning is driven by a salt ...


Role Of Protein Charge In Reversed Micellar Extraction , Craig Everett Forney Jan 1994

Role Of Protein Charge In Reversed Micellar Extraction , Craig Everett Forney

Retrospective Theses and Dissertations

This work was performed to investigate the role of charge on the efficiency of reversed micellar extraction. This was accomplished using charged fusion proteins, proteins which had been genetically altered to contain regions not only of extra charge but also regions of high charge density. The enzyme glucoamylase from Aspergillus awamori was altered to have poly(aspartate) tails at either the amino terminus (Asp-Tyr-(Asp) [subscript]n-Lys-Ala-Arg, with n = 4 or 9) or the carboxyl terminus (Met-Ala-(Asp)[subscript]n-Tyr, with n = 0, 5, or 10), with one mutant carrying tails of 5 aspartic acids at both termini;The fusions ...


Ultrafiltration Behavior Of Polyelectrolyte And Protein Mixtures, Scott J. Blonigen Jan 1994

Ultrafiltration Behavior Of Polyelectrolyte And Protein Mixtures, Scott J. Blonigen

Retrospective Theses and Dissertations

A number of nonchromatographic separation techniques have been developed previously in which polyelectrolytes are used as separating agents to reduce the cost or enhance the selectivity of protein purification techniques. This work examines the potential of ultrafiltration to separate a protein from a smaller polyelectrolyte.;The ultrafiltration behavior of two polyelectrolytes, poly(acrylic acid) (PAA) and polyphosphate, were examined individually and in mixtures with the protein, bovine serum albumin (BSA), using dead-end and hollow fiber crossflow ultrafiltration systems. Dead-end ultrafiltration was used to study the flux decline and retention behavior of 1000, 10,000, and 30,000 molecular weight cutoff ...


Fusion Proteins Containing The Starch-Binding Domains Of Glucoamylase And Cyclodextrin Glucanotransferase , Bipin Kumar Dalmia Jan 1994

Fusion Proteins Containing The Starch-Binding Domains Of Glucoamylase And Cyclodextrin Glucanotransferase , Bipin Kumar Dalmia

Retrospective Theses and Dissertations

This work addresses the interactions of a starch-binding domain (SBD) from glucoamylase-I (GA-I) of Aspergillus niger with raw starch and a possible application of the SBD as an affinity tail for a single-step recovery and purification of fusion proteins from crude cell extracts, using native starch granules as an adsorbent;Our previous studies indicated that GA-I adsorbed specifically and strongly to raw corn starch primarily via its SBD, which is located at the C-terminus of the enzyme molecule. A [beta]-galactosidase ([beta]-gal) fusion protein (BSB119) containing the C-terminal 119 aminoacids from GA-I showed significantly higher affinity for starch than ...


Water And Electrolyte Regulation During Space Flight And Exercise , Susan Elizabeth Doty Jan 1994

Water And Electrolyte Regulation During Space Flight And Exercise , Susan Elizabeth Doty

Retrospective Theses and Dissertations

When one is exposed to microgravity, fluid which is normally pooled in the lower extremities is redistributed headward and weight bearing bones begin to demineralize due to reduced mechanical stresses. The kidney, which is the primary regulator of body fluid volume and composition, responds to the fluid shift and bone demineralization by increasing the urinary output of water, sodium, and calcium. This research involves developing a mathematical description of how water and electrolytes are internally redistributed and exchanged with the environment during space flight. Various levels of activity are also considered, since it is believed that exercise can prevent some ...


Interactions Of Hydrogen With Alkali Promoted Ru/Sio2 Catalysts: A Proton Nmr Study , Deniz Ozbay Uner Jan 1994

Interactions Of Hydrogen With Alkali Promoted Ru/Sio2 Catalysts: A Proton Nmr Study , Deniz Ozbay Uner

Retrospective Theses and Dissertations

The work completed for this dissertation has endeavored to characterize alkali promoted Ru/SiO[subscript]2 catalysts. Initial work investigated the role of hydrogen spillover to the silica support on the characterization of the active metal sites via a hydrogen chemisorption technique. A strongly bound component of spilled over hydrogen was found in the silica support which interfered with accurate measurements of active metal sites via volumetric strong hydrogen chemisorption techniques. Based on the results of this work, the volumetric chemisorption technique was modified such that typical measurement times were reduced from 12-36 hours to 1 hour for silica supported ...