Examination of the Soil Bacteria Responsible for the Decomposition of Ailanthone, an Inhibitory Chemical in Ailanthus altissima

Ailanthus altissima produces the inhibitory chemical ailanthone, which is primarily found in the roots and bark of maturing trees. The goal of this project was to determine under what soil conditions ailanthone decomposes. Ailanthone broke down in slightly basic conditions and non-sterile soil while remaining stable in sterile soil. This suggests that ailanthone is broken down by soil microbes. The next phase in this project was isolating the soil bacteria that may be responsible for ailanthone decomposition in soil. Soil bacteria were successfully cultured from soil samples near A. altissima trees using a structurally similar compound to ailanthone, quassin, for selection

What It Does, Where It Does It, and How To Market It: Creative Problem Solving Impact Catalog for Marketing.

This project contains a spreadsheet and data catalog that show documented impacts of Creative Problem Solving (CPS), the domains/industries in which they occurred, what type of CPS application was used, and the literature that provided the information. This information is cross-referenced to determine good target markets according to type of CPS product, what domain/industry is being sold to, and what type of impact is being sought. Analysis of marketing materials determined the information sought, which in turn influenced the categories of data used on the spreadsheet. All materials are contained in the appendixes catalog for easy reference

Deactivation and regeneration of immobilized titanium dioxide photocatalysts during treatment of pharmaceutical micropollutants in groundwater

As detection methods improve, a number of classes of emerging contaminants are being detected in natural waters, including many pharmaceuticals and personal care products (PPCPs). Many of these chemicals are recalcitrant to conventional treatment processes, so new treatment methods are being investigated. Titanium dioxide (TiO2)-based photocatalytic treatment has proven to be an effective method for degrading trace organic contaminants, including PPCPs. However, most studies on photocatalytic treatment of PPCPs to date have been conducted in short-term batch experiments using fresh catalysts in laboratory solutions devoid of non-target constituents that are often abundant in natural water matrices (e.g., Ca2+, HCO3-, natural organic matter). In this contribution, we describe the results of an investigation of the long-term stability and deactivation of immobilized TiO2 photocatalysts used to treat PPCPs in groundwater (GW). GW spiked with four model PPCPs (5 µg/L atenolol, sulfamethoxazole, carbamazepine, and 10 µg/L iopromide) was treated with immobilized thin films of TiO2 coated on glass slides under UV-A light in a serpentine plug-flow reactor. Initially, catalysts achieved 50-75% degradation of influent PPCPs using a 2-hr reactor residence time (higher removal can be achieved using longer residence times). Over one month of continuous operation, catalyst films developed visual discoloration and the extent of PPCP removal in the reactor diminished, eventually reaching complete catalyst deactivation for some of the target PPCPs. Calcite (CaCO3(s)) with smaller quantities of iron and copper were detected on the surface of deactivated catalyst films when analyzed by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Treatment of deactivated catalysts with 10 mM hydrochloric acid was able to restore catalyst activity to pre-GW levels, so introduction of recurrent acid washing stages during GW treatment were investigated to prolong catalyst activity. Pretreatment of GW using a sodium-loaded cation exchange softening resins was investigated to eliminate calcite precipitation in the reactor. Although calcite precipitation was eliminated, catalysts continued to experience a similar loss of activity observed for unsoftened GW. Analysis of catalyst surfaces after exposure to softened groundwater indicates deposits of zinc, copper, iron, and manganese. Results suggest that both physical blocking of active sites by calcite surface precipitates and adsorption of trace metals contribute to catalyst deactivation. Further work is needed to investigate other pretreatment methods such as pH modification to prevent surface deposition of catalyst-deactivating metal species on the TiO2 surface and prolong reactor activity between acid washing regeneration stages

Effects Of Iron Limitation And Carbon Source On Extracellular Excretions And Intracellular Carbon Metabolism In Pseudomonas Putida

Iron (Fe) is an important micronutrient in soils, essential for bacterial growth and carbon metabolism, serving as an enzymatic cofactor for many central carbon metabolic reactions. It has limited bioavailability due to being embedded in Fe oxide and hydroxide minerals. Bacteria secrete high-affinity metal-binding molecules, or siderophores, along with low-affinity organic acids to cope with Fe limitation and facilitate mineral dissolution. In the research presented, I investigated the role of available carbon sources (glucose, succinate, acetate, and citrate) on the secretion of these molecules from the ubiquitous soil bacteria Pseudomonas putida and their effectiveness in dissolving Fe from common soil minerals. Fe limited cells secreted the siderophore pyoverdine in addition to secreting higher levels of small organic acids. Dissolution experiments were carried out with bacterial secretions, substrates, and detected organic acids to determine the amount of Fe released with each organic compound. Overall, bacterial secretions were more effective in dissolving Fe than the individual substrates and organic acids. Additionally, to elucidate the changes in metabolic flux with respect to Fe, kinetic and steadystate isotopic labeling experiments were performed with [U-13C] and [1,2-13C] glucose under Felimited and replete conditions. Steady-state experiments were also performed with [2,3-13C] succinate under Fe-replete conditions to compare changes in metabolic flux between carbon sources. Overall, most fluxes decreased under Fe-limited conditions with glucose as the sole carbon source, but the flux to the amino acid precursor phosphoenolpyruvate increased. The succinate flux model showed a decrease in flux through the citric acid cycle under Fe-replete conditions, with a corresponding decrease in the amount of CO2 produced compared to Fereplete glucose. These findings indicate that the secretion of organic molecules is substrate and Fe dependent, as are the carbon fluxes through the pathways of the central carbon metabolism