Saturated fat has a good potential for improving emulsion stability and products texture. However in the past ten years, food industry has intended to reduce its amount to prevent its impact on heart diseases. Therefore a better understanding of fat crystallisation has been studied to design the final properties of fat systems by changing the formulation and process of crystallisation. Fat crystallisation occurs in several stages like nucleation, crystal growth and fat network formation. Adding emulsifiers or waxes has demonstrated the possibility to change the process of crystallisation by promoting primary or secondary nucleation as a function of additive concentration. The head group size of emulsifiers has also exhibited an influence on fat crystallisation by promoting secondary nucleation with glycerol or primary heterogeneous nucleation with sorbitol. Furthermore waxes differing by their single or multi-component nature, have induced secondary and primary nucleation respectively. The process of crystallisation has been changed by applying different cooling rates and shear rates; increasing the cooling rate increased the number of nucleation sites and shear could enhance the interactions between fat and emulsifiers. Finally formulation and process have displayed the design of the final texture and allowed a reduction in saturated fat of 50 % while keeping the same network strength.

Two-stage roll milling of chocolate pastes was studied to investigate the relationships between roll speeds and pressing force with mass processing rate, product particle size and roll torque. A three-roll mill was used, operating in two and three-roll mode for each stage, respectively. A strong correlation (R2=0.97) was found between the size of the largest particles and the surface coverage of the discharge roll. No evidence was found of shear rate affecting the size of the largest particles (p=0.13). Negative torque values were measured on the slower rolls under higher forces and/or speed ratios. The minimum specific mechanical energy input (S\(M\(E\(I) was observed to occur for the lowest pressing force that still resulted in satisfactory material transfer. Theoretical models based on the lubrication approximation (LAT), with and without pressure-dependent viscosity, resulted in lower apparent viscosities found at faster roll speeds, higher speed ratios and/or greater forces. The observed tendency for the material to detach from the slow roll suggests that higher shearing action in the slow boundary causes a greater reduction in paste-roll adhesion, provided that material cohesion exceeds adhesion. A comparison with full 2D FEM solutions revealed differences no greater than 0.02% in the pressure and velocity profiles.

This thesis is concerned with tackling three major challenges of melamine formaldehyde (MF) microcapsules for delivering of core materials: reducing the formaldehyde content in the formulation, modulate the mechanical properties and reducing the leakage of the core material through the microcapsules. Thus, to reduce the formaldehyde content in the microcapsules, a low formaldehyde to melamine (F/M) molar ratio (0.20-0.49) compared to the conventional literature formulations (2.30-5.50) was used to produce the MF microcapsules in this study. It was found that there is a relatively small window of F/M molar ratio between 0.20 and 0.49 in which the wall thickness and nominal rupture stress of the microcapsules can be modulated significantly. Above 0.49 increases in F/M molar ratios only increase these properties marginally. Furthermore, to reduce the leakage of the microcapsules, organic/inorganic double shell composite microcapsules with MF/copolymer as the inner shell, and ripened CaCO\(_3\) nanoparticles as the outer shell were produced. A ~20 fold reduction in leakage was observed between the double shell composite microcapsules and the MF microcapsules by the end of 24 hours, and it was also found that the mechanical properties of these double shell composite microcapsules are dominated by the CaCO\(_3\) nanoparticles outer wall. Finally, calcium shellac matrix containing MF microcapsules and unripened CaCO\(_3\) nanoparticulate microcapsules (complex capsules) were also produced to reduce the leakage. A ~37 fold leakage reduction between calcium shellac matrix containing MF microcapsules and MF microcapsules alone by the end of 20 days was observed, and a ~14 fold reduction was found between calcium shellac containing unripened CaCO3 nanoparticulate microcapsules and the unripened CaCO\(_3\) nanoparticulate microcapsules alone.

Clostridium autoethanogenum is an important organism for biofuel production. Other 'omics' approaches have been used to understand the mode of operation of the organism but metabolomics gives information on the cellular activities in the cell. Metabolomics combined with other 'omics' data can provide a deeper understanding for pathway interpretation. This project sets out to develop an analytical method that is suitable for analysis of highly charged polar compounds found in C. autoethanogenum metabolic pathways. Also investigate suitable isotope labelled internal standards to improve matrix effects to the metabolites as a result of the biological matrix. A high-throughput hydrophilic interaction liquid chromatography isotope dilution mass spectrometry (HILIC-IDMS) was developed and validated using high resolution hybrid orbital trap MS for both targeted and untargeted metabolomics analysis of intracellular metabolic pathways of Clostridium autoethanogenum. Extraction of intracellular metabolites from C. autoethanogenum was achieved using a specifically developed sample preparation protocol using freeze thaw cycles (freeze in liquid nitrogen and thaw on ice repeated 3x). A total of 133 metabolites were monitored and validated. Limits of detection (LODs) ranged from 0.001 µM to 5 µM reported for compounds such as NADPH and NADH. Limits of quantification (LOQs) for all metabolites ranged from 0.001 µM to 10 µM for metabolites such as glucose-6-phosphate and glyceraldehyde-3 phosphate. Precision and accuracy were evaluated for all metabolites and found to be within the acceptable limits of ±15 % with few exceptions for some nucleotides and organic acids. Stable isotopically labelled internal standards were generated from C. pasteurianum cells that provided coverage for about 100 metabolites. This enabled absolute intracellular concentrations to be obtained in combination with the estimated cell volume of C. autoethanogenum that was obtained from microscopy and flow cytometry measurements. The developed HILIC-IDMS method was applied to various solvent production optimisation experiments conducted using C. autoethanogenum and the main findings are reported below. In chapter 4, the HILIC-IDMS method was applied to C. autoethanogenum in an experiment where the pH of the media was reduced to improve ethanol and solvent production. The metabolomics studies of this experiment gave intracellular concentrations that differentiated the acidogenic phase from the solventogenic phase. A total of 86 metabolites were quantified in this experiment. Intermediates in the tricarboxylic acid (TCA) cycle were the most affected during the acidogenic/solventogenic transition. Metabolites concentrations were used for metabolic pathways analysis to understand the pathways affected during the pH shift. The pathway analysis also confirmed the TCA cycle was the most affected pathway during the acidogenic/solventogenic transition. In chapter 5, The HILIC-IDMS method was applied to a gas shift experiment to optimise ethanol and solvent production. Gas shift is another approach that can be used to optimise solvent production in similar as the pH shift experiment. The use of gas shift to induce solventogenic phase can be difficult as C. autoethanogenum has little tolerance for high levels of CO hence the increase in gas (CO) flow rate has to be done in a gradual fashion. Equally, TCA intermediates were observed to be the most affected as observed in the pH shift experiment. In chapter 6, the method was applied to a study where pantothenate and phosphate concentrations in the growth media of C. autoethanogenum were reduced to increase ethanol production. Pantothenate is the precursor for coenzyme A (CoA) production and metabolomics study confirmed a decrease in CoA concentration when pantothenate concentration was reduced. Metabolomics also showed decrease in concentration of metabolites directly linked to CoA synthesis such as L- Aspartate. Metabolic pathway analysis also confirmed the pantothenate and CoA biosynthesis and its associated pathways were the most affected pathways during the pantothenate-limiting phase. Both targeted and untargeted metabolomics analysis were performed on these nutrient-limiting experiments and there were clear differences between the two different conditions before and after nutrient limitation. Supervised multivariate data analysis using OPLS-DA was used to compare higher pantothenate and low pantothenate concentration and there were clear separation and clustering between the two conditions. Cross validation obtained for R2Y and Q2 were 0.993 and 0.941 respectively. OPLS-DA plots for phosphate limitation also showed clustering and separation between the high phosphate concentration and reduced phosphate concentration with R2Y and Q2 0.981and 0.837 respectively. In conclusion, a novel high-throughput HILIC-IDMS method was developed and validated for analysis of different classes of polar compounds in bacteria. The method has the potential to be applied in other biological matrices for coverage of diverse range of polar compounds.

The aim of this thesis is the investigation of the use of a RAFT agent developed by the company Lubrizol, BMDPT (Butyl-2-methyl-2-[(dodecylsulfanylthiocarbonyl) sulfanyl] propionate) produced in tonnes scale to make amphiphilic block copolymers in ester solvent (butyl acetate and methoxypropyl acetate). For this purpose, a broad range of monomers including acrylate, methacrylate and styrenic containing tertiary amine were polymerised and used as pigment dispersants. As the starting point, the reactivity of n-butyl acrylate (n-BA) and di(methyl)aminopropyl acrylate (DMAEA) monomer followed by the synthesis of acrylate diblock copolymers in acetate solvents (butyl acetate and methoxypropyl acetate) are investigated. The second chapter is focused on the methacrylate polymerisation which is a large body of work of this thesis. The poor reactivity of the trithiocarbonate RAFT agent towards methacrylate monomer was already published few times. Consequently, the kinetic studies of butyl methacrylate (BMA) and di(methyl)amino ethyl methacrylate (DMAEMA) was investigated in batch mode. Subsequently, a new synthetic route is explored to reach a well-controlled diblock copolymers. In the third chapter, a novel class of amphiphilic diblock copolymer containing acrylate and a mixture of styrene and maleic anhydride is explored. Then, the functionalisation of polymer backbone is carried out by using an amine in order to insert an anchoring group for pigment affinity. Finally, the efficiency of all the diblock copolymers on carbon black pigment dispersion is reported. A combination of different techniques such as dynamic light scattering (DLS), transmission electronic microscopy (TEM) and thermogravimetric analysis (TGA) are used to investigate the interaction between the polymer and the pigment.

This thesis investigates the degradation and release of a fluorescent dye from biodegradable microparticles. Particular attention is given to determining the effect of polymeric properties on the subsequent microparticle degradation and release rate. Chapter 1 reviews the current polymerisation techniques for the synthesis of polyesters and introduces the synthetic procedures and degradability currently attainable for biodegradable microparticles. The concept of ‘smart’ release technology is introduced and the potential for using biodegradable ‘smart’ particles for enhanced agricultural formulations is explored. In Chapter 2, the ring-opening polymerisation (ROP) of a variety of polyesters is demonstrated, including an investigative study on the ROP of poly(3-hydroxybutyrate) (PHB) using magnesium 2,6-di-tert-butyl-4-methylphenoxide (Mg(BHT)2(THF)2). The polyesters are used to prepare microparticles via a single oil-in-water solvent evaporation technique, a range of formulation parameters are studied to enable optimisation of the subsequent particle size and stability. Chapter 3 investigates the encapsulation of a model fluorescent dye into poly(L-lactide) (PLLA) microparticles and the subsequent PLLA particle degradation and dye release under simulated environmental conditions is reported. Chapter 4 describes the degradation and release of 3-bromo-4-(butylamino)-2,5-dihydro-1H- pyrrole-2,5-dione (ABM) from a range of polyester microparticles, investigating the effect of polymer properties (e.g., molecular weight, crystallinity, etc.) on the particle degradation and release rate. In Chapter 5, the incorporation of a stimulus responsive polymer using optimised particle synthesis and degradation conditions (detailed in Chapter 2 and 3) is investigated. The successful tuneable microparticle degradation and release is described by incorporation of a light-responsive poly(nitrobenzyl malic acid) (PNO2BnMA) into homopolymer blends of PLLA microparticles. Chapter 6 explores the synthesis of degradable poly(vinyl acetate) (PVAc) microparticles by the incorporation of 2-methylene-1,3-dioxepane (MDO) degradable ester linkages into the polymer backbone via free radical ring-opening polymerisation (rROP) and post- polymerisation microparticle synthesis (using the optimised solvent evaporation technique detailed in Chapter 2). The successful encapsulation of ABM into P(MDO-co-VAc) microparticles is reported and compared to encapsulation into PVAc microparticles. In Chapter 7, the synthesis of poly(ω-pentadecalactone) (PPDL) microparticles using the optimised single oil-in-water emulsion technique (Chapter 2) is reported. Investigation into the synthesis and degradation of films prepared from random copolymers of PPDL and poly(ɛ- caprolactone) (PCL) is described. An attempt at polymerisation-induced self-assembly (PISA) using block copolymers of PPDL and poly(ɛ-decalactone) (PeDL) is demonstrated. In chapter 8, a general summary of Chapters 2-7 is presented and key findings and conclusions highlighted. Chapter 9 provides the experimental methods used throughout this thesis and Chapter 10 provides supporting degradation studies for Chapter 3 and 4.

Currently, fossil fuels contribute a large number of high value chemicals that are used on a daily basis. Crude oil is cracked to give a number of high value chemicals, including vehicle fuels as well as chemicals and solvents that are used daily both commercially and industrially. However, fossil fuel reserves are in decline, with research going into alternatives to obtain these useful chemicals, one of which is biofuels. Biofuels can be generated in a number of ways, one of which is the fermentation of acetogenic bacteria, microorganisms that generate acetate as a product of anaerobic metabolism. Clostridium autoethanogenum is an acetogen that can grow on one carbon gases as its feedstock, and can be used to generate valuable chemicals, with scope to develop the range of metabolic products further. One aim of this project was to investigate the metabolic flux through pathways of the bacterium using isotopically labelled compounds, which would be assessed by mass spectrometry and NMR. Following on from this, design of inhibitors for the enzymes of the pathways with a view to drive the metabolic processes towards higher value chemical compounds by ‘switching off’ other branches of the pathway. Putative small molecule mimics of acetyl-CoA, SNAC thioesters, were synthesised and tested for uptake and activity in whole cell growth experiments with C. autoethanogenum, and determined to be unsuccessful. Further to this, compounds were designed and synthesised to replace pantothenic acid in the growth media, which were not tested in growth experiments. A library of inhibitor compounds was synthesised and tested against recombinantly purified acetate kinase. A number of compounds were shown to inhibit the enzyme, and the mode of inhibition was determined, as well as IC50 and Ki values for each. This project operated as part of a larger GASCHEM project in the Synthetic Biology Research Centre at the University of Nottingham.

This thesis is concerned with the preparation, and subsequent investigation of, titanium dioxide (TiO2) nanomaterials and their ability to remove phenol from gas streams for application towards the abatement of polluted land fill gas (LFG). Using the well documented ability of TiO2 to excite an electron by UV light, phenol was removed from gas streams to investigate the efficacy of TiO2 nanomaterials. Phenol was chosen as a representative VOC but the catalysts were proven to also remove four other organic compounds during gas phase photocatalysis. It was found that in loadings of 1 mol % the degradation of phenol could be increased relative to pristine TiO2 nanofibres. The activity of six metal oxide dopants were fairly compared to one another where it was found that cobalt doped TiO2 showed very high activity, more so than P25 powder. Furthermore, mono-metallic cobalt nanomaterials were shown to degrade phenol in the gas phase, however, more studies are required on these materials. Supports for TiO2 were investigated in order to provide a more practical catalyst for industrial continuous flow reactors. These included novel zeolite:titania composites which were fibrous, non-woven mats of these materials were prepared by electrospinning and were shown to effectively remove phenol from polluted gas stream.

The focus of the work presented here is the theoretical description of the photodissociation of molecular systems possessing low-lying singlet 3s/\(\pi\)σ* states that are quasi-bound with respect to an N-H bond. Model Hamiltonians are developed for and subsequently used in quantum dynamics simulations of the photo-induced dynamics of the molecules ammonia, 3-pyrroline, pyrrole, and aniline. The origin to the barrier to dissociation in ammonia's first excited state is identified and the effect of vibronic coupling of this state to a number of higher-lying states on the dissociation dynamics of the molecule is assessed. A conformer-resolved study of the dynamics of 3-pyrroline following excitation into its first two excited states is performed, and the first two bands in its electronic spectrum are calculated and analysed. The first band in the electronic spectrum of pyrrole is calculated, its vibrational structure assigned and the role played by intensity borrowing in its formation analysed. The dynamics of aniline following excitation to its first to singlet \(\pi\)\(\pi\)* are studied. Two previously neglected 3p Rydberg states are found to play important roles in aniline's excited state dynamics. The first two bands in aniline's electronic absorption spectrum are calculated, and the role played by the Hertzberg-Teller effect in the first band is analysed

This study aimed to study the effect of potential large-scale bioreactor environmental heterogeneities during fed-batch culture on the performance of an industrially-relevant GS-CHO cell culture, producing an IgG antibody. Heterogeneity was created by a two-compartment scale-down model, using a well-mixed stirred tank reactor (STR) and plug flow reactor (PFR). A peristaltic pump was used to continuously circulate cell culture from the STR through the PFR. Standard culture parameters were measured and flow cytometry was used to indicate cell viability and mode of cell death. The results essentially fell into two categories: those without circulation and those with it. In all cases with recirculation, whether nutrients and alkali were added into the STR or the PFR, significantly decreased culture duration (\(\sim\)48 hours shorter) and antibody titre (\(\sim\)20% decrease) were found compared to those experiments without circulation. It was impossible to conclude anything concerning the impact of bioreactor heterogeneities. Nevertheless, damage associated with peristaltic pumping has relevance to the many aspects of cell culture processes that require transfer of cells in suspension. The 'squeezing' motion of peristaltic pumps may impose sufficient mechanical stress to have decreased cell culture performance. The high biocompatibility of the materials used suggests long-term incompatibility is less likely.