The development of processes for sustainable energy and chemical production is of great importance for the health of our planet. Utilising suitable feedstocks such as renewable resources and existing waste streams is central to making such processes a reality. Microorganisms can be employed in the processing of a diverse range of such feedstocks, offering unique routes of production for useful and valuable chemical products. Acetogenic organisms, capable of fermenting single carbon (C1) feedstocks are especially interesting from the perspective of industrial application. Their natural metabolism and biochemistry enables fixation of low energy C1 compounds, under conditions which would typically be unfeasible with traditional chemical catalysts. Genetic research and development of new acetogenic species opens the door to industrially feasible, and economically attractive, sustainable bioprocessing. This study outlines the genetic development of the methanol and syngas fermenting acetogen E. limosum. This includes establishing gene-transfer and genetic engineering tools in this organism for first time. Additionally, we demonstrate the genetic engineering of synthetic metabolic pathways in this strain to enable production of valuable chemicals, acetone and isopropanol. Gene-transfer is a cornerstone of modern genetic research in microorganisms, and so effective methods of establishing it are of significant value. We present the development of an improved methodology for enabling and enhancing gene transfer in recalcitrant microorganisms which contain active restriction modification (RM) systems. The method harnesses lambda-red recombineering to support the rapid creation of tailored methylation donor (MD) strains for the preparation and protection of transforming plasmids. The process is uniquely designed in a manner which enables compatibility with both electroporation and conjugation methods of gene transfer.

Environmental concerns have brought attention to the requirement for more efficient and renewable processes for chemicals production. Lignin is the second most abundant natural polymer, and might serve as a sustainable resource for manufacturing fuels and aromatic derivatives for the chemicals industry after being depolymerised. In this work, two main approaches were investigated with the aim of treatment of lignin with a mediator, 2,2’-azinobis(3-ethylbenthiazoline-6-sulfonic acid) diammonium salt (ABTS), in 1-ethyl-3-methylimidazolium ethyl sulfate, ([C2mim][C2SO4]). In the first approach, laccase from Trametes versicolor (LTV) was used to treat organosolv lignin, using [C2mim][C2SO4] as a co-solvent in the presence of ABTS. LTV was shown to possess catalytic activity for the degradation of organolsov lignin in systems containing ionic liquid and syringaldehyde was found to be a major product obtained from the process. ABTS alone has been evaluated for its reaction with lignin by means of cyclic voltammetry (CV). Here, the non-phenolic lignin model compound veratryl alcohol and three types of lignin (organosolv, Kraft and lignosulfonate) were specifically examined. The presence of either veratryl alcohol or organosolv lignin increased the second oxidation peak of ABTS under select conditions, indicating the ABTS-mediated oxidation of these molecules at high potentials in [C2mim][C2SO4]. Furthermore, CV was applied as a quick and efficient way to explore the impact of water in the ABTS-mediated oxidation of both organosolv and lignosulfonate lignin. Higher catalytic efficiencies of ABTS were observed for lignosulfonate solutions either in sodium acetate buffer, or when [C2mim][C2SO4] (15% v/v) was present in an aqueous solution, whilst there was no change found in the catalytic efficiency of ABTS in neat [C2mim][C2SO4]-lignosulfonate mixtures relative to ABTS alone. In contrast, organosolv showed an initial increase in oxidation, followed by a significant decrease on increasing the water content of a [C2mim][C2SO4] solution. Despite enhanced lignin solubility in ionic liquids, the yields of small molecules attributed to depolymerisation in ionic liquids are often quite low. Since depolymerisation approaches examined herein are thought to proceed via free-radical mediated mechanisms, two different stable radicals 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ABTS were assessed for the rapid monitoring of radical activity of lignin-related compounds in ionic liquid systems. While these assays are successful in aqueous and organic solvent systems, the presence of the ionic liquids complicates the assay procedure, requiring further developmental work.

Dosators (and other machines operating on generally similar principles) are widely used in the pharmaceutical industry for dosing products that are delivered to the customer in powder form (i.e. capsules and dry inhaled powder applications). However a significant problem for this technology is the ability to predict how accurately and reliably, new formulations can be dosed from these machines prior to scale-up for manufacture. Dosator filling machines have been on the market for over forty years, and their mechanisms have been refined over the time; in parallel with development work of formulation scientists. Despite the work that has progressed in both of these important fields, there has been only a limited improvement in the understanding of how the formulations behave when introduced into production line equipment. Typical problems include variation in potency and manufacturing dose weight – both being issues that can be difficult to predict and counter (especially where mainly the manufacturing process is undertaken on a batch basis). Many manufacturing problems can be traced back to an inadequate understanding of the bulk properties of the powders at the formulation stage. Common issues encountered during full scale production include extended commissioning; high levels of out of specification materials (specifically through dose weight variation). The project aims to provide a predictive tool to industry, the use of which can improve manufacturing efficiency, minimise costs and risk when launching new products. The approach proposed focuses on the development of an analytical model for the pick up and discharge of powder into and out of dosators, based upon established particle/powder characterisation techniques combined with an improved understanding of dosator machine factors, constitutive models and geometry of the machine. The model will be used to predict fill dose weights and filling/discharge behaviour of new products in dosator fillings systems; likewise, to investigate what changes in powder flow properties mean to dosator operation. Recommendations for the practical use of flow property measurement techniques in conjunction with the model are also outputs from this project. To simulate the process and (very importantly) validate the model, a dosator single shot testrig was engineered at The Wolfson Centre to measure forces acting on the dosator during the filling stage, the force required to eject the dose and the dose weight. In addition other important aids, such as a dosator demonstrator and an ultimate bearing application of soil mechanics, are key in the understanding of the process and estimate the stress distribution occurring in the stages of the operation. In addition, the development of this research provides a better understanding of the compaction phenomena in dosator operation, and more importantly, critical flow properties and machine settings factors compromising the uniformity of the fill dose weight in production lines using dosator filling machines not mentioned in the literature yet. Although this project has focussed on dosators, the general concept could be applicable to other volumetric powder filling systems.

Concerns about climate change and energy supply security have led to a focus on using biofuels to replace oil-based fuels in the transport sector. Second generation biofuels (SGBs), which are produced from lignocellulosic material such as wheat straw, are currently being developed. This project investigated wheat straw supply for SGB production, focusing on the use of dual-purpose cultivars (DPCs) that are optimised to provide for both food and SGB markets. The project consisted of: agronomic assessment of cultivars and management practices for traits associated with a DPC; economic assessment of the value of these DPCs to farmers and costs of straw delivery; life cycle assessment for quantifying environmental burdens associated with straw production from DPCs; and a farmer survey for quantifying current straw supply and potential future straw supply should a new market for straw emerge. Agronomic trials did not identify any outstanding candidates for use as DPCs from currently grown wheat cultivars or any management practices that would benefit DPC traits. Economic assessment found that straw production costs were lower than the straw price but the overall straw gross margins were much lower than grain gross margins suggesting that grain yield would not be traded off against increased straw yield. Transport costs were slightly lower with the use of DPCs. Environmental burdens for straw production were found to be lower than in other studies but the allocation process had a large influence. From the survey, 50% of respondents were willing to increase straw yields but even with a very generous price of straw, 21% of respondents would not supply additional straw. The work suggests that straw availability is lower than some current estimates and there is only limited scope to increase straw yield through cultivar selection.

There is a continuing need for improvements in the cryopreservation of clinically relevant cells, tissues and organs as advances in transplantation science and regenerative medicine rise alongside an aging populace that intensifies demand. Antifreeze (glyco)proteins (AF(G)Ps) and antifreeze proteins (AFPs) are classes of proteins found in cold acclimatized species. Ice recrystallization is a highly damaging process that occurs upon the thawing of frozen specimens with AF(G)Ps and AFPs limiting this effect in a process termed ice recrystallization inhibition (IRI). However AF(G)Ps and AFPs largely fail to improve in vitro and ex vivo cryopreservation due to their secondary property of dynamic ice shaping. The biocompatible and synthetically accessible polymer poly(vinyl alcohol) (PVA) has been shown to process a strong IRI activity. The IRI property of PVA along with numerous other polymers and polyols is investigated to highlight the uniqueness of PVA (Chapter 2). PVA is then explored as a cryoprotectant with red blood cells (Chapter 3), immortalized mammalian cell lines (Chapter 4) and primary cells (Chapter 5) with a significant advantageous effect observed with each cell type in terms of the number of cells recovered post thaw. However, this is despite the use of proportionately low concentrations of PVA compared to traditional membrane permeable cryoprotectants. The application of PVA as a cryoadjuvant could therefore improve the cryopreservation of cells, tissues and organs resulting in widespread clinical benefits.

New energy materials have been investigated, including hydrogen storage materials and dilute nitride semiconductors. The two potential hydrogen storage materials to have been investigated are di-sodium amide borohydride (Na2NH2BH4) and lithium sodium borohydride (LiNaBH4). Additionally, the homoepitaxial growth of InNSb and GaNSb across a range of growth temperatures and rates has been examined and the effect of annealing GaNSb layers grown on GaAs has also been studied. It has been shown that Na2NH2BH4 undergoes a first order phase transition between a low temperature orthorhombic phase and a high temperature cubic phase. There is a large coexistence region between the two phases of -10°C to 70°C. The relative percentages of each of these phases in this region are dependent on whether the sample is been heated or cooled and the rate of change of the temperature, leading to a discrepancy in the overall volume of the sample between heating and cooling. It has also been proved that there is a metastable cubic phase of the sample that is seen when this material is first formed and cooled. Phase pure samples of LiNaBH4 have been synthesised from mixtures of sodium borohydride and lithium borohydride, with varying amounts of lithium inclusion. This lithium inclusion has resulted in some disorder in the sodium borohydride structure of the samples up to temperatures of 200°C, which disorder is increased as the amount of lithium increases. The inclusion of lithium has reduced the hydrogen desorption temperature by c.a.10% from 550°C for pure sodium borohydride to 504°C for the sample with the most lithium inclusion. Both InNSb and GaNSb exhibit a linear relationship between growth temperature and amount of nitrogen inclusion, with both more nitrogen being included and a greater maximum growth temperature seen in the GaSb-based material. In both types of material higher growth rates have resulted in less nitrogen inclusion at a given temperature. It has been shown that the increased amount of nitrogen inclusion has improved the quality of the grown layer. Annealing of hetroepitaxially grown GaNSb has increased the amount of substitutional nitrogen in these layers by allowing interstitial nitrogen to diffuse on to the crystallographic B site of the material, at higher temperatures this effect has been reversed. Increased nitrogen incorporation has resulted in a reduction in the crystal quality of these layers, differing from the effects seen in the homoepitaxial layers.

The research conducted can be split into three major regions; pigment material, a simulation program called QuadFit and mesoporous oxides. There has also been some extra work conducted on a catalyst for partial hydrogenation of vegetable oils. Various techniques have been used on the different systems including XPS, STEM and 77Se, 17O, 93Nb, 15N, 119Sn, 27Al, 115In and 63,65Cu static and MAS NMR. The pigment materials consist of a series of materials which are grouped under the F-Colours project. The pigments consist of sulphur doped tin niobates, copper indium sulphur selenide doped zinc selenides, sulphur doped tin tungstates and colloidal gold and silver enamels. The sulphur doped tin niobate study shows a conversion from foordite to pyrochlore and also where the sulphur sits in the structure. The copper indium sulphur selenide doped zinc selenide study shows the indium and copper moving into the zinc selenide as copper indium pairs. However, how the pairs sit in the structure remains undetermined. The sulphur doped tin tungstate study shows that the sulphur acts as a promoter for the beta phase rather than the desired alpha phase. The enamels based on gold and silver show that the tin site does not determine the colour of the enamel and the silver-gold association is likely to be the dominant factor. Mesoporous oxides show a link between the amount of mesoporous structure and their temperature stability. The nitrogen spectra of the template in the material shows that in the mesoporous silicate (which has the largest surface area) there is a breakdown of the amine into NH groups which does not appear in the other mesoporous materials. This could lead to a method of increasing the surface area of the other mesoporous oxides. QuadFit has the ability to simulate quadrupolar and CSA interactions with distributions of interactions whilst static and the quadrupolar interaction with distributions under MAS. The program is written in Java so will run on most platforms and also has near perfect stability.

The majority of work presented covers an investigation in to vegetable oil based monomers for use in low ‘volatile organic compounds’ (VOC) or VOC free paints. Chapter 1 provides an introduction to recent EU legislation into the reduction of VOCs in a wide variety of paints and coatings. This is followed by an overview of vegetable oil based chemistry and subsequently the use of vegetable oils within materials, specifically coatings. Chapter 2 discusses the synthesis of a selection of vegetable oil derived monomers using a number of different diamines and aminoalcohols to produce fatty amides with methacrylate, styrene and maleate functionalisation. A selection of 3 vegetable oils with varying degrees of unsaturation (soybean oil, rapeseed oil and cocoa butter) were trialled to see the effect the starting oil had on the subsequent monomers. Removal of some or all of the unsaturation within the fatty chains of the triglycerides and monomers was carried out, primarily as a way to potentially reduce yellowing often found in paints derived from a vegetable oil source. Chapter 3 introduces the technique of emulsion polymerisation, followed by the incorporation of a selection of the methacrylate monomers synthesised in the previous chapter into polymer latexes. Comparisons of the latex properties are made and the results of a variety of tests (DSC, MFFT, hardness, yellowing ability) described. Comparisons between unsaturated and epoxidised derivatives are made and conclusions drawn. Chapter 4 focuses on the preparation of polyurethanes (PU) from a small library of renewable diols. These were synthesised using both cocoa butter and rapeseed oil with diethanolamine, followed by epoxidation of the residual unsaturation in some cases. These were reacted with MDI and a variety of commercial diols (PEGs and 1,4-butanediol) and their physical properties (tensile strength, Young’s modulus, swelling and cross-linking density) and thermal properties analysed by a variety of methods (TGA, DSC). Chapter 5 describes the BF3.Et2O catalysed ring-opening of a small range of epoxidised oils derived from rapeseed and cocoa butter to give higher molecular weight pre-polymers/oligomers suitable as polyols for PU synthesis. Two approaches to the monomers are described. Chapter 6 describes the experimental conditions and chemical analysis of the all the key reactions and processes described in the thesis.

The work presented in this thesis represents the chemical modifications of unsaturated plant oils to yield oligomeric/polymeric polyols suitable for polyurethane synthesis. Chapter 1 provides the introduction to the chemistry of polyurethanes, plant oils and plant oil based polyols. Chapter 2 focus on making oligomeric polyols from unsaturated plant oils through epoxidation and subsequent epoxide ring opening oligomerization that yielded oligomeric polyols. The properties of these oligomeric polyols were influence by the level of unsaturation of the plant oils. In addition, catalyst loading, monomer concentration and reaction time play vital role in determining the properties of the oligomeric polyols. Plant oil based polyols were also prepared by epoxide ring opening with renewable polyhydric alcohols that provide a variety of plant oil based polyols for polyurethane synthesis. Chapter 3 focus on the synthesis of polyurethanes (PU) from various types of plant oil based polyols as well as the evaluation of the mechanical properties of these synthesized PU. The tensile test of the PU shows that the mechanical properties were related to the structure and functionalities of the plant oil based polyols. The bulk of Chapter 4 discusses the copolymerization of epoxidized plant oils with tetrahydrofuran and the use of these copolymers for the synthesis of PU. The properties of the copolymers were related to the epoxidized oils used in the reaction and therefore influence the mechanical properties of the PU synthesized from them. Finally, Chapter 5 is a collection of work on the one-pot oligomerization of unsaturated fatty acid and plant oils with and without catalyst as well as the synthesis of PU based on these polyols.

The work described in this thesis was carried out on the synthesis of silicon carbide using microwave processing and aimed to develop procedures to reduce processing complexity and cut processing times. Si-C/SiO2-C systems were first studied due to the ready availability at reasonable cost of the starting powders and the excellent microwave absorption properties of carbon. Silicon carbide was synthesised from silicon or silica combined with activated carbon or graphite via microwave heating over timescales from minutes to seconds without the need for inert atmospheres or subsequent purification. In the reactions performed in a MMC, graphite was found fundamental not only as a microwave susceptor, but also as a reductant, preventing the oxidation of silicon carbide. Another important beneficial factor was water, used as a binder in the pellet making process, it minimised the intergrain void space between particles and possibly acted as a polar liquid microwave susceptor. It was found the carbide morphology and phase purity can be controlled by the microwave cavity used, the power applied and hence by the heating rate. Short irradiation times (ca. 5 minutes) in a multimode cavity using silicon and activated carbon powders produced single phase β-SiC nanofibres as small as 5 nm in diameter while large crystallites of β-SiC can obtained in ~1 minute using high power, single mode cavity microwave techniques. Furthermore, similar microwave cavity systems shown that the removal of the susceptor, starting from silica and carbon mixtures, is possible and the successful conversion to silicon carbide can be performed using loose powders. This represented a major step with respect to designing a flow process and reducing carbon contamination. Studies of microwave processing of silicon carbide were then extended to x-aerogels, to probe whether the produced silicon carbide would mimic the porous microstructures offered by the precursor. This indeed resulted in the production of porous silicon carbide (in 15 minutes) and also sintered crystallites of micrometre sizes (after 3.5 minutes) whether MMC or SMC systems were employed.