Enhanced Biological Phosphorus Removal (EBPR) is an established process in wastewater treatment that uses bacteria to reduce phosphorus levels below regulatory discharge limits. Recently, in light of growing political concern over phosphorus sustainability, EBPR has also been recognised as a platform from which phosphorus may be recovered and recycled onto land as fertiliser. Operating EBPR to optimise performance and efficiency is therefore extremely important, but remains a challenge due to poor understanding of these bacterial ecosystems. Raman spectroscopy is a non-invasive, label-free, culture-independent technique capable of analysing live, single cells. Despite its advantages, Raman spectroscopy has been applied to study EBPR bacteria in just a handful of studies and thus has a low profile in this field of research. More work is required to investigate potential areas of application for Raman spectroscopy in EBPR research. The principal thesis presented here is that Raman spectroscopy could be used as a tool to improve EBPR. The Raman spectra used for this investigation were acquired from individual EBPR bacteria dried onto a calcium fluoride substrate. The bacterial samples were collected from three different sources, namely lab-scale sequencing batch reactors located in Edinburgh (University of Edinburgh, UK) and Boston (Northeastern University, USA), and a full-scale EBPR plant in Slough (Thames Water, UK). Using these spectra, some potential applications and limitations of Raman spectroscopy for improving EBPR were explored. In this foundation work, a particular emphasis on spectral analysis methods was kept in light of the benefits of automating analysis as well as the need for standardisation to be able to compare results between different studies and groups. Nine methods were compared for baselining Raman spectra of individual EBPR bacteria. From these, the “small-window moving average” (SWiMA) method was determined to be the best baselining technique for our purposes at the current time. In agreement with earlier studies, the Raman spectroscopic signatures of three key EBPR metabolites – polyphosphate, polyhydroxyalkanoate (PHA) and glycogen – were shown to be clearly identifiable in individual EBPR bacteria when present. The Raman shifts of characteristic spectral bands arising from polyphosphate were shown to vary significantly between samples and the implications of this were discussed. Examples of how the Raman spectra of individual bacteria can be modelled with multivariate tools to open up new areas for research were given. MCR modelling was demonstrated to offer a novel way to normalise the Raman spectra of individual EBPR bacteria prior to quantitative analysis. With the instrumental set-up in this work, the limit of detection (LOD) of aqueous polyphosphate samples was estimated to be approximately 0.08 M and 0.02 M for 10 second and 200 second acquisitions respectively. Future work is required to research ways in which a more comparable form of polyphosphate ‘standard’ might be prepared so that direct correlation can be drawn between measurements made on such a standard and measurements made in bacterial cells. Overall, several applications and challenges of Raman spectroscopy for the investigation of EBPR bacteria are presented in this work together with recommendation for how to process the spectral data. The conclusions drawn from this work indicate that Raman spectroscopy could be used as a tool to improve EBPR but further work is required to refine and apply these methods.

<p>Although microbes may strongly influence wetland phosphorus (P) cycling, specific microbial communities and P metabolic processes have not been characterized in wetlands, and microbial P cycling is poorly understood across global ecosystems, especially in soils. The goal of this work is to test the effects of stress and growth factors on microbial communities in wetlands, and on microbial P metabolism and P cycling at ecosystem scales in wetland soils and beyond. I conducted field and laboratory research experiments in wetland soils, which by definition lie along gradients between terrestrial and aquatic ecosystems, and I explicitly compared results in wetlands to adjacent ecosystems to improve inference and impact. </p><p> To test relationships between microbial communities, soil stress and resource supply, I compared the distribution and abundance of uncultured bacterial communities to environmental factors across a range of wetland soils including a well-characterized P enrichment gradient, and restoration sequences on organic soils across freshwater wetland types. The strongest predictor of bacterial community composition and diversity was soil pH, which also corresponded with the abundance of some bacterial taxa. Land use and restoration were also strong predictors of bacterial communities, diversity, and the relative abundance of some taxonomic groups. Results from wetland soils in this study were similar to both terrestrial and aquatic ecosystems in the relationship of pH to microbial communities. However, patterns of biogeography I observed in wetlands differed from aquatic systems in their poor relationships to nutrient availability, and from terrestrial ecosystems in the response of microbial diversity to ecosystem restoration.</p><p> Accumulation of inorganic polyphosphate (PolyP) is a critical factor in the survival of multiple environmental stresses by bacteria and fungi. This physiological mechanism is best characterized in pure cultures, wastewater, sediments, and I used 31P-NMR experiments to test whether similar processes influence microbial P cycling in wetland soils. I surveyed PolyP accumulation in soils from different wetland types, and observed PolyP dynamics with flooding and seasonal change in field soils and laboratory microcosms. I found PolyP accumulation only in isolated pocosin peatlands, similar to patterns in the published literature. I observed rapid degradation of PolyP with flooding and anerobic conditions in soils and microcosms, and I characterized the biological and intracellular origin of PolyP with soil cell lysis treatments and bacterial cultures. While degradation of PolyP with flooding and anaerobic conditions appeared consistent with processes in aquatic sediments, some seasonal patterns were inconsistent, and experimental shifts in aerobic and anaerobic conditions did not result in PolyP accumulation in soil slurry microcosms. Similar to patterns in wetlands, I found prior observations of PolyP accumulation in published 31P-NMR studies of terrestrial habitats were limited to acid organic soils, where PolyP accumulation is thought to be fungal in origin. Fungal accumulation of PolyP may be useful as an alternative model for PolyP accumulation in wetlands, although I did not test for fungal activity or PolyP metabolism. </p><p> To evaluate relationships between microbial P metabolism and growth, I compared concentrations of P in soil microbial biomass with the soil metabolic quotient (qCO2) by compiling a large-scale dataset of the carbon (C), nitrogen (N) and P contents of soils and microbial biomass, along with C mineralization rates across global wetland and terrestrial ecosystems (358 observations). The ratios of these elements (stoichiometry) in biomass may reflect nutrient limitation (ecological stoichiometry), or be related to growth rates (Biological Stoichiometry). My results suggest that the growth of microbial biomass pools may be limited by N availability, while microbial metabolism was highly correlated to P availability, which suggests P limitation of microbial metabolism. This pattern may reflect cellular processes described by Biological Stoichiometry, although microbial stoichiometry was only indirectly related to respiration or metabolic rates. I found differences in the N:P ratios of soil microbial biomass among ecosystems and habitats, although high variation within habitats may be related to available inorganic P, season, metabolic states, or P and C rich energy storage compounds. Variation in microbial respiration and metabolic rates with soil pH suggests important influences of microbial communities and their responses to stress on metabolism and P cycling.</p><p> My dissertation research represents early contributions to the understanding of microbial communities and specific processes of microbial P metabolism in wetlands, including PolyP accumulation and Biological Stoichiometry, which underpin microbial cycling of P and C. Together, my research findings broadly indicate differences in microbial P metabolism among habitats in wetlands and other ecosystems, which suggests the prevailing paradigm of uniform P cycling by microbes will be inadequate to characterize the role of microbes in wetland P cycling and retention. While I observed some concomitant shifts in microbial communities, PolyP accumulation, and microbial stoichiometry with soil pH, land use, and habitat factors, relationships between specific microbial groups and their P metabolism is beyond the scope of this work, but represents an exciting frontier for future research studies.</p> / Dissertation

A modern approach to the treatment of localized disease involves the use of advanced polymeric or ceramic implant materials for controlled-rate drug delivery. These implants are dynamic systems that maintain drug concentrations within the optimal therapeutic window via complex hydration, swelling, and degradation processes. To optimize the performance of these materials, however, requires a fundamental understanding of the mechanisms that govern drug release. Magnetic resonance imaging (MRI) provides a means of non-invasively characterizing the microstructure and transport properties in this type of material, and has proven to be an invaluable tool for their advancement. Calcium polyphosphate (CPP) is a biomaterial that has shown promise as a degradable matrix for drug delivery and bone defect repair. Release rates are potentially governed by hydrogelation, swelling, and polymer chain scission. CPP bioceramics have previously been studied using models for drug elution, but these tend to be simplistic and unable to explain the many interrelated mechanisms. Structural analysis techniques have also been applied, but these tend to be inherently destructive and unable to characterize the material in situ. With the aim of characterizing degradation/drug release mechanisms, a non-invasive approach based on MRI was developed and optimized for imaging two existing types of CPP device. Techniques included mapping of the T1 and T2 relaxation times and the apparent diffusion coefficient (ADC), which together provide sensitivity to local fluid transport parameters. The non-destructive nature of MRI permitted longitudinal observation, and structural degradation effects were investigated by correlation with concurrent drug elution measurements. Temporal variation in the release mechanisms was treated by analyzing elution in stages. Large variation between samples was found, but on average, drug elution that was controlled by a structural-relaxation mechanism appeared correlated with the gradual formation of a highly-mobile ``free'' water component within the disk. Other characteristics, such as swelling rate, did not appear to correlate with drug release at all. While the data did not implicate a singular, governing scheme for drug release from CPP bioceramics, the approach did yield an assessment of the relative importance of the various contributing mechanisms.

Porous constructs of calcium polyphosphate (CPP) are under investigation as a substrate for tissue engineering of cartilage for repair of osteochondral defects. Previous studies have shown that CPP has the required features to satisfy these requirements. However, its degradation rate is lower than desired. This study investigated the effect of doping with MgCO3, MgCl2, K2CO3 or KCl at a molar ratio of M/Ca = 0.02 on sintering and in vitro degradation behavior of CPP. Doping with magnesium or potassium improved the tensile and compressive strengths of CPP at similar porosities. After 15 days of aging in phosphate buffer saline, the rate of tensile strength loss was faster for the doped CPP groups than undoped CPP. The chemical degradation rate of Mg-doped CPP groups was the fastest among CPP groups. The chemical degradation rate of K-doped CPP groups was slower than undoped CPP.

Porous constructs of calcium polyphosphate (CPP) are under investigation as a substrate for tissue engineering of cartilage for repair of osteochondral defects. Previous studies have shown that CPP has the required features to satisfy these requirements. However, its degradation rate is lower than desired. This study investigated the effect of doping with MgCO3, MgCl2, K2CO3 or KCl at a molar ratio of M/Ca = 0.02 on sintering and in vitro degradation behavior of CPP. Doping with magnesium or potassium improved the tensile and compressive strengths of CPP at similar porosities. After 15 days of aging in phosphate buffer saline, the rate of tensile strength loss was faster for the doped CPP groups than undoped CPP. The chemical degradation rate of Mg-doped CPP groups was the fastest among CPP groups. The chemical degradation rate of K-doped CPP groups was slower than undoped CPP.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O trabalho reporta o estudo da formaÃÃo de um novo coacervato preparado a partir da mistura de soluÃÃes aquosas de polifosfato de sÃdio e nitrosilos complexos de rutÃnio. Foram utilizados os nitrosilos complexos cis-[Ru(bpy)2(L)(NO)]n+, com L=1-metilimidazol (MeimN), imidazol (ImN) ou sulfito (SO32-). A formaÃÃo dos coacervatos se mostrou possÃvel alterando a metodologia tradicional pela adiÃÃo de etanol. Com relaÃÃo à caracterizaÃÃo dos coacervatos a espectroscopia eletrÃnica na regiÃo do UV-Vis mostra as bandas caracterÃsticas dos complexos indicando a presenÃa deles nos coacervatos. A espectroscopia de absorÃÃo na regiÃo do infravermelho indica que apÃs a coacervaÃÃo, o oxido nÃtrico (NO) mantÃm-se coordenado ao complexo na forma NO+ sugerindo que os coacervatos nÃo interferem no estado de oxidaÃÃo do NO nos complexos. Os espectros de ressonÃncia magnÃtica nuclear de 1H apontam a presenÃa dos ligantes (L) que fazem parte da esfera de coordenaÃÃo dos complexos, mais uma vez sugerindo a presenÃa dos complexos nos coacervatos. Os resultados mostram que à possÃvel controlar a quantidade de complexo no coacervato simplesmente aumentando a quantidade de complexo no inÃcio da mistura. Os resultados mostram que as soluÃÃes de polifosfato e os coacervatos exercem um efeito muito interessante no processo de conversÃo nitrosilo-nitro. Em soluÃÃes de polifosfato o processo de conversÃo ocorre lentamente em pH 7,0 enquanto nos coacervatos o complexo permanece estÃvel por atà 12 meses sem sofrer conversÃo. O processo de conversÃo foi monitorado por espectroscopia eletrÃnica a regiÃo do UV-Vis pelo deslocamento da banda de transferÃncia de carga metal-ligante (MLCT) de 332nm para 450nm. A liberaÃÃo do Ãxido nÃtrico foi estudada nos coacervatos em testes baseados na reduÃÃo fotoquÃmica e na reduÃÃo quÃmica. Em ambos a liberaÃÃo foi possÃvel mostrando que os complexos nos coacervatos mantem sua capacidade de liberadores de NO. / This work reports the preparation of a new coacervate by mixture of aqueous solution of sodium polyphosphate and nitrosyl ruthenium complexes. The complexes used were: cis-[Ru(bpy)2(L)(NO)]n+, where L = 1-methylimidazole (MeimN), imidazole (ImN) and sulfite (SO32-). The preparation of the coacervates is possible only when ethanol is used. In accord of characterization of the coacervates the electronic absorption spectroscopy (UV-Vis) shows the characteristics bands of complex indicating their presence in the coacervates. Even after the preparation of the coacervates the infrared spectra show the presence of the NO+ group. Therefore, the preparation doesnât change the form (oxidation state) of the NO ligand attached in the complexes. The nuclear magnetic resonance (NMR) 1H spectra have showed the signals of the hydrogen of the ligands into the coordination sphere of the complexes. Several compositions to coacervates are possible only changing the initial concentration of the complexes into mixture. The aqueous solution of sodium polyphosphate and the coacervates have showed interesting features related to conversion process nitrosyl-nitro. The conversion process nitrosyl-nitro occurs slowly into aqueous solution of the sodium polyphosphate at pH 7,0 but into the coacervates thereâs no evidence of conversion process nitrosyl-nitro during 12 months. The shifting of the metal-ligand charge-transfer (MLCT) band from 332nm to 450nm was used to evaluated the conversion process nitrosyl-nitro by electronic absorption spectroscopy (UV-Vis). The release of the nitric oxide in the coacervates was induced by photochemical and chemical reduction. In both situations the release occurred and the complexes showed the properties of the nitric oxide releasing.

No description available.

The increasing population with its associated rising food demand requires more agricultural fertilizers to maintain the harvest for food security. However, the natural calcium carbonate phosphate mineral (carbonate apatite) used to produce phosphorus (P) fertilizer is a non- renewable ore. Therefore, in this study, the objective is to extract the inorganic polymeric phosphate (polyphosphate: polyP) P-component in waste activated sewage sludge (WAS) from Ottawa’s municipal wastewater plant (ROPEC). Once extracted, the goal was to break down the polyP to inorganic phosphate (Pi) to produce carbonate apatite. PolyP is a P-component in WAS because a group of wastewater microorganisms called polyphosphate-accumulating organisms uptake phosphate and generate intracellular polyP stores during aerobic digestion in municipal wastewater treatment plant processes. The total acidic, oxidative P content of WAS was measured. PolyP was extracted and quantified to estimate the fraction of total P as polyP in WAS. Different polyP extraction methods were undertaken. It was determined that the complicated composition and weight fractions of TWAS, including iron phosphate, complicated polyP extraction and Pi measurement. Lessons learned were applied towards preliminary batch and continuous precipitation of carbonate apatite with the product slurry from the anaerobic digestion process at ROPEC. Limestone was tested as an inexpensive calcium carbonate source for carbonate apatite precipitation. The dissolution of calcium and carbonate from limestone was assessed, and it was determined that further optimization is required. Preliminary work indicated that the calcium- carbonate solution from limestone could precipitate synthetic carbonate apatite from anaerobic digester material. This synthetic carbonate apatite product may lead to mitigating the impending limitations on natural carbonate apatite availability for P-fertilizer production.

The first report of polyphosphates (polyP) was in 1890 by L. Liberman and since then, polyP’s role in biology has been explored. PolyPs are chains of phosphoanhydride-linked inorganic phosphates ranging from 3-1000s of units in length. These chains are implicated in many cellular pathways including blood clotting, bacterial virulence, and neuroproteotoxic disease. Given the diversity of polyP, they make an excellent candidate in the development of novel therapeutics. In yeast, polyP is synthesized by the vacuolar transporter chaperone (VTC) complex as a translocation event into the vacuole lumen. In 2015, polyP chains were found to act as a post-translational modification termed polyphosphorylation on yeast proteins (Nsr1 and Top1). This modification occurs non-enzymatically on lysine residues within poly-acidic, serine, and lysine (PASK) motifs and can only be detected via electrophoretic mobility shift on NuPAGE gels. We have since expanded the pool of yeast polyphosphorylated substrates to 25, with an enrichment of proteins with roles related to RNA biology. Additionally, we were the first group to demonstrate polyphosphorylation of 6 human proteins by expressing E. coli PPK1 in HEK293T cells. We next focused on elaborating how polyP is being regulated via the VTC complex by assessing which protein trafficking pathways are critical for VTC localization at the vacuole membrane. We found the adaptor protein 3 (AP-3) complex is responsible for localizing Vtc5 subunit to the vacuole membrane and in AP-3 mutants, Vtc5 becomes mislocalized to the vacuole lumen and degraded. Vtc5 degradation, upon AP-3 mutation, is mediated by the endosomal sorting complex required for transport (ESCRT) complex. The loss of polyP in AP-3 mutants is imparted by Vtc5 mislocalization. In humans, mutations in AP-3 cause a rare genetic disorder termed Hermansky-Pudlak Syndrome (HPS) which has a wide range of symptoms. These include defects in polyP accumulation in platelets, likely related to a loss of polyP. We expect that our work using yeast will provide a framework for understanding fundamental aspects of polyP biology related to HPS and other health conditions.

Polymer composites are used in a varying extent and are challenging the use of traditional materials due to the push towards sustainable development. They have replaced steels and aluminum alloys in applications. Polymer composites are used in load-bearing and semi-load bearing applications in automotive, transport and aerospace industry due to their good characteristics. Polymer poses beneficial characteristics such as chemical stability, corrosion resistance, attractive strength-to-weight ratio, and be processed with ease. However, many polymers are highly flammable, making them a fire hazard. The fact that polymer composite is highly flammable, they need to undergo fire safety treatment that are sustainable towards the environment and humans. In this study biochar and ammonium polyphosphate (APP) were added in different combinations to epoxy resin. The purpose was to evaluate the synergistic effects that biochar and APP has on epoxy composite and how it will affect the fire- and mechanical properties. Additionally, developing a composite that retains a high compressive strength while increasing its thermal stability. Lastly, evaluate if the best performing composite could be recommended for load/semi-load‑bearing applications along with being sustainable towards the environment and humans. This thesis was conducted through literature study and laboratory work where three different tests were done such as cone calorimeter (CC), thermogravimetric analysis (TGA) and compressive test. The CC and TGA test were done to analyze the synergistic effect APP and biochar had on epoxy composites fire properties, but also determine which composition obtained the best fire properties. The compressive test was done to analyze the synergistic effect APP and biochar had on the epoxy composites mechanical properties. From the CC- and TGA tests it was observed that biochar and APP individually improved the fire properties of the epoxy where a decrease in peak heat release rate per unit area (PHRRPUA) and a decrease in mass loss was obtained. Additionally, it was noticed that the addition of only APP had a greater impact in improving the fire properties compared to only biochar. However, a combination of 15 wt.% biochar and 20 wt.% APP improved the fire properties the most. The compression tests indicated that biochar reduced the compressive strength drastically compared to the neat epoxy, since the biochar-based samples exhibited a porous structure. The addition of only APP in the epoxy showed a minimal reduction in compressive strength compared to neat epoxy. In conclusion, biochar and APP were improving the fire properties of epoxy composite whereas the compressive strength decreased. Overall, by an addition of only APP to the epoxy, the fire properties were enhanced where the compressive strength was conserved compared to neat epoxy. Since the composition with only APP performed the best overall, this composition can thereby be recommended for development in load/semi-load-bearing applications.