Industry operations require a clean plant to make safe, quality products consistently. As well as product quality, the environmental impact of processes has become increasingly important to industry and consumers. Cleaning In Place (CIP) is the ubiquitous method used to ensure plant cleanliness and hygiene. It is therefore vital the system is optimal and efficient. I.e. the correct cleaning agent is delivered to the fouled surface at the right time, temperature, flow rate and concentration. This cannot be assured without effective online measurement technologies. Fryer and Asteriadou (2009) describe how the nature of a fouling deposit can be related to the cost of cleaning. The evolution of three key deposit types has also enabled current fouling and cleaning literature to be easily classified. In the brewery there are many types of soil that need to be cleaned of which the cost of cleaning was unknown. The cost of fermenter CIP in one brewery was found to be £106 k per year. Effective fouling methods for yeast and caramel; and the relationship between flow, temperature, and caustic concentration in the removal of yeast and caramel soils seen in industry has been done. This work has helped determine effective cleaning methods for these soils from stainless steel coupons and pipes. Fermentation vessels have been found by Goode et al., (2010) to have two types of soil: A – fouling above the beer resulting from the act of fermentation, and B – fouling below the beer resulting from emptying the fermenter. The type B fouling below the beer was found to be a type 1 soil that could be removed with water. An increase in flow velocity and Reynolds number decreased cleaning time. An increase in temperature did not decrease cleaning time significantly at higher flow velocities, 0.5 m s-1. Fouling above the beer occurs when material is transported to and stick on to the wall during fermentation foaming. This happens initially and as a result the fouling has a long aging time. This yeast film represents a type 2 deposit, removed in part by water and in part by chemical. Most of the deposit could be removed by rinsing with warm water. At 50°C the greatest amount of deposit was removed in the shortest time. A visually clean surface could be achieved at all temperatures, 20, 30, 50 and 70°C, using both 2 and 0.2 wt % Advantis 210 (1 and 0.1 wt % NaOH respectively). A visually clean surface was achieved quicker at higher detergent temperatures rather than rinsing at higher flow velocity or concentration. This finding suggests most deposit can be removed with warm water and cleaned with lower detergent concentrations. Currently in the brewery 2 % NaOH is used at 70°C. Caramel represents a type 3 soil. When heated it sticks to stainless steel and requires chemical action for removal. Confectionary caramel was cooked onto pipes and coupons and the effect of flow velocity, temperature and concentration on removal determined. At high flow velocity most of the deposit could be removed from the pipe using water. There was no significant difference in the mass of caramel removed by the water however. A visually clean surface was achieved by rinsing at 80°C with 2.5% Advantis. A visually clean surface could not be achieved at lower temperatures at higher concentration, 5% Advantis, or at higher flow velocity. The measurement of online conductivity and flow rate values was invaluable during each experiment. Turbidity values did indicate the removal of yeast and caramel from pipes however offline measurements were required to confirm removal. Caramel removal could be wholly quantified by mass when cleaning pipes. The integration of the turbidity values measured during each rinse correlated well with the mass of deposit removed in most cases. Coupon cleaning was wholly quantified by area . A cost saving of £69 k can be made by optimising fermenter CIP to warm pre-rinsing followed by ambient caustic circulation. An £8 k saving can be made by optimising yeast tank CIP to pre-rinsing only and acid sanitisation. Industry must ensure effective online CIP measurements are made throughout cleaning to describe the process effectively and enable optimisation. It is crucial to have cleaning measurement information to hand because that is how we ensure our customers they are buying a quality product. Also you cannot optimise what you do not measure effectively.

In modern times we have become increasingly reliant on mammalian cell culture for the production of biopharmaceuticals; therefore research aimed at improving the characteristics of the cell-lines being used for recombinant protein production is essential. In this study I have examined the hypothesis that the creation of a CHO cell-line in which the expression of p21 \(^C\)\(^I\)\(^P\)\(^1\)and Bcl-2 could be combined would un-couple cell growth from cellular proliferation resulting in a significant increase in both the rate of production and culture viability. Analysis of key metabolites together with changes in cell volume, total protein and mitochondrial activity indicate that following the initiation of p21\(^C\)\(^I\)\(^P\)\(^1\)-expression cells undergo an increase in their protein synthesis machinery and that the energy, previously required for cell division may be diverted towards cell growth and product formation. In addition to the requirement of cell-lines with high production capacities, the biopharmaceutical industry is under constant pressure to develop growth media able to facilitate high yields without the need for the addition of protein or serum. This means it is often necessary to adapt high producing cell-lines to growth in such a defined chemical environment, a process which has proven to be both extremely long and costly. In this thesis I have successfully developed a method for the swift adaptation of commercially important cell-lines to growth within a chemically defined bio-processing environment. I have shown that the expression of p21\(^C\)\(^I\)\(^P\)\(^1\)is able to reduce the need for extracellular growth factors and that by combining the expression of p21\(^C\)\(^I\)\(^P\)\(^1\) and Bcl-2 it is possible to further reduce the time required for successful adaptation, supporting the well established theory that Bcl-2 plays an important role in apoptotic signaling pathways.

The hydrogen permeability of surface modified Pd\(_6\)\(_0\) Cu\(_4\)\(_0\) wt% (Pd\(_4\)\(_7\)\(.\)\(_3\)Cu\(_5\)\(_2\)\(_.\)\(_7\)at%) membranes have been determined for the first time. Surface modification was accomplished through the deposition of Pd thin films of three different thicknesses (95.5 ± 0.1, 797.4 ± 0.2 and 1,409.6 ± 0.2 nm) on to one side of a range of as-received Pd\(_6\)\(_0\) Cu\(_4\)\(_0\) wt% membrane coated with a 1,409.6 ± 0.2 nm thick Pd thin film positioned on the feed side (445 kPa of hydrogen pressure) and cycled between 50 and 450 °C achieved the highest hydrogen permeability of 1.09 x 10\(^-\)\(^8\) mol m\(^-\)\(^1\) s\(^-\)\(^1\) Pa\(^-\)\(^0\)\(^.\)\(^5\) at 450 °C during the third cycle. This is a 58% increase on the value measured for the as-received Pd\(_6\)\(_0\) Cu\(_4\)\(_0\) wt% under the same conditions. This improvement can be attributed to a Pd-rich Pd-Cu face centred cubic (FCC) phase forming through interdiffusion between the Pd thin film and bulk Pd-Cu membrane as a result of the test conditions used during hydrogen permeability measurements. This introduces a larger hydrogen concentration gradient across the membrane due to the relatively high hydrogen solubility of the Pd-rich Pd-Cu FCC phase resulting in the observed increase in permeability.

A problem with the Polymer Electrolyte Fuel Cell (PEFC) is the expensive platinum (Pt) electrocatalyst. This thesis aims to investigate alloying of Pt with cheaper metals that not only reduce the overall cost but also alter the electronic properties to improve reaction kinetics. A Genetic Algorithm (GA) coupled with Density Functional Theory (DFT) approach has been used to perform structural searches on small Pt clusters doped with early transition metals (M). It is found that varying spin can have significant effects on the minimum energy structures of pure Pt clusters, while doping with early transition metals leads to spin quenching. DFT studies have been performed to predict potential Pt-based alloy nanoparticles that will result in weaker Pt–O interactions. This is achieved by investigating nanoalloys that lead to filling of the Pt d-band. Early transition metals are found to be promising, where donation of electron density from M to Pt results in additional filling of the Pt d-band. The surfaces of pure Pt clusters are found to distort, facilitating fast oxygen dissociation. It is found that the strong Pt-M interactions, which lead to filling of the d-band, can lead to Pt clusters becoming more structurally rigid, which inhibits oxygen dissociation. A search has been performed to find the best compromise for a system that retains flexibility of the Pt surface, to allow fast dissociation while also allowing M to Pt electron donation, leading to filling of the Pt d-band.

There is increasing clinical need for bone substitutes because of the limited supply of autogenous tissue, and the significance of inherited or other bone diseases. The ultimate aim of this study was to form calcium phosphate (CaP) based matrices as bone grafts for medical applications. Amongst CaP based materials, CaP gels made by the sol-gel process have attracted much interest since they can be processed at room temperature allowing the incorporation of environmentally sensitive molecules such as growth factors. CaP gels can be engineered by changing process conditions. There is little previous work however on the effect of drying regimes on the CaP materials formed using the sol-gel process. The objectives of this research were to investigate the influence of drying conditions on the physicochemical properties of CaP gels and the effect of the resultant structures of CaP gels on the function of the incorporated therapeutic molecules. In addition, surface modification of the CaP gels was investigated as a means to enhance biological interaction and also a potential way of creating primary bonds between apatite crystals enabling mechanical reinforcement of the material, which is currently too weak to bear load. This work has confirmed that different drying regimes have a significant influence on the formation of the gel pore structure, with the storage of gel in humid conditions, enabling reprecipitation of an apatitic phase. This variation in pore structure has a significant influence on the catalytic of encapsulated enzymes. In addition, the pH fluctuation of CaP based matrices during processing determines the activity of biomolecules after incorporation. It has also been shown that it is possible to form thiol functional groups on the surface of CaP gels, which could be used in future for mechanical reinforcement or for the attachment of biological moieties.

Hydrogen is seen as a potential fuel for the future; its choice is driven by the increasing awareness of the necessity for clean fuel. Together with the simultaneous development of “green technologies” and sustainable development, a current goal is to convert waste to energy or to create energy from a renewable resource. Biological processing [of renewables] or bioremediation of waste to create hydrogen as a product fulfils this goal and, as such, is widely researched. In this work, an already established process, using a hydrogenase up‐regulated strain ‐ was characterised and the important process parameters were established. This bacterial strain has the potential for industrial‐scale hydrogen production from, for example, waste sugars. Previous work, repeated here, showed that hydrogen could be generated by E. coli HD701 using a two‐phase process (growth in shake flasks, followed by hydrogen production within a bioreactor). Ideally a commercial process would need to be in a single vessel (bioreactor), which therefore resulted in this investigation of the scale‐up of twophase fermentations to 5 L stirred tank bioreactors. Within the initial two‐phase process, shake flask growth in 2 L shake flasks (employing a 50% working volume) achieved a dry cell weight of 1.33 +- 0.1 mg mL‐1 which then, when transferred to a 5 L bioreactor (containing 2 L of culture and 2 L of hydrogen production substrate), achieved a maximum hydrogen production rate of (200 mL h‐1) 150 mL g(dcw)‐1 h‐1. The first step in scale‐up was to simply transfer the process to a bioreactor and see the effect it had on hydrogen production. This approach did not yield any hydrogen and therefore consequent experimentation sought to see if the hydrogen production was growth phase dependant. However all phases of growth evolved no hydrogen upon the addition of substrate. The next approach was to take the conclusion drawn from a literature survey that showed a need for microaerobiosis or anaerobiosis during growth (for mixed acid fermentation to occur) along with a high formate concentration necessary for the transcription of the FHL complex (the hydrogen gas evolving enzyme). For this reason the KLa from the initial shake flask growth (calculated from literature correlations) was applied to the bioreactor. Experiments used to simulate the shake flask mass transfer coefficient (kLa) in a bioreactor did not generate hydrogen; the physical system within the shake flask used for growth in the initial process allows for this to occur, but the consequent process change to a bioreactor did not. This inability to produce hydrogen was concluded to be due to the lack of microaerobiosis/anaerobiosis required for mixed acid fermentation (the metabolic precursor to hydrogen production). The criterion of KLa was inappropriate for scale up in this case due to the physical differences between the shake flask and the bioreactor, as the oxygen transfer within the shake flask is not limited to transfer between the liquid and gas phase (the effect of transfer across the shake flask closure must be considered). This fact led to the novel use of gas blending for dissolved oxygen tension control. Gas blending was used in a bioreactor to track the changes observed during growth in the shake flask. This created a process that mirrored the shake flask in both growth and hydrogen production. The outcome was a dry cell weight of 1.34 +- 0.02 mg mL‐1 and a maximum hydrogen production rate of 200 mL h‐1 i.e. 150 mL g(dcw)‐1 h‐1, exhibiting almost identical process results to the two‐stage process. This characterisation reinforced the necessity for microaerobiosis during growth to allow subsequent post‐growth hydrogen production. Microaerobiosis in the latter stages of growth allows mixed acid fermentation to occur, which was found to be essential for hydrogen production. Process intensification took place by increasing cell density. This was achieved by increasing the medium concentration, then by changing the medium (two differing fed batch media were chosen; each medium used was experimentally linked with multiple feeds) and finally by utilising the novel technique of combining gas blending with fed batch cultivation to ensure microaerobiosis during growth. This, along with the use of a low (\(\mu\)=0.05 h‐1) growth rate for feed calculation, led to an eight‐fold increase in cell density. The low growth rate was employed to reduce inhibitory acetate formation while the multiple feeds were used to investigate nitrate depletion. The maximum increase in cell density led to a hydrogen evolution rate of 1800 mL h‐1, thus producing hydrogen that could be converted into energy at a rate eleven‐fold greater than the rate at which it consumed energy for agitation.

Despite the fact that around 20000 cups of coffee per second are produced worldwide (making coffee the second most-traded commodity in the world), coffee extraction is not well understood yet. This Engineering Doctorate Thesis seeks to advance the fundamental engineering understanding of coffee extraction. This aim is based on the current need of industry to optimise soluble coffee process (as stress on water and energy is increasing), and the growing popularity of On-Demand coffee systems. The macrostructure, microstructure and extraction parameters of roast and ground coffee were investigated. The findings from this study were used in a multi-scale extraction model that portrays the extraction of coffee soluble solids as the combination of phenomena taking place at the particle scale (~μm), and the packed bed scale (~cm). Effective diffusion coefficients in the range of 10\(^-\)\(^1\)\(^1\) m\(^2\) s\(^-\)\(^1\) were shown to offer the better fit to experimental data if a single effective diffusion coefficient is to be used. The model was shown to predict literature extraction data for caffeine, chlorogenic acids and trigonelline in espresso coffees. A new methodology to estimate the permeability of roast and ground coffee in steady state was also developed. Permeability values resulted to lie between 10\(^-\)\(^1\)\(^3\)-10\(^-\)\(^1\)\(^4\) m\(^2\).

Heavy oil and bitumen are known to constitute high-boiling molecules which gives them characteristic high viscosity, high density/low API gravity, low yields of fuel distillates, and high heteroatom content compared to light oil. Upgrading therefore refers to the breaking down of heavy oil into oil with similar characteristics as light crude oil. The toe-to-heel air injection (THAI) and its catalytic add-on CAPRI (CAtalytic upgrading PRocess \(In-situ\)) were developed to achieve this objective down-hole. In this study, the CAPRI process was explored with the objective of controlling catalyst deactivation due to coking while increasing the extent of upgrading. The effects of reaction temperature and weight hourly space velocity on the extent of upgrading were studied in the range of 350-425\(^o\)C and 9.1-28 h\(^-\)\(^1\), respectively. In order to control premature deactivation of the catalysts due to coke and metal deposition, the following were investigated activated carbon guard-bed on top of the catalyst bed, hydrogen-addition, steam environment as a source of hydrogen-donor, and nanoparticulate catalyst. It was found that high reaction temperature of 425\(^o\)C and lower WHSV (9.1 h\(^-\)\(^1\)) improved the cracking as well as increase API gravity (~3-7\(^o\)), viscosity reduction of (81.9 %), demetallisation (9.3-12.3 %), desulphurisation (5.3-6.6 %), and higher yield of fuel distillates, respectively compared to upgrading at 350 and 400\(^o\)C. In spite of the improvement in produced oil at 425 \(^o\)C, the carbon-rejection was high (51-56.6 wt.%) compared to (42-47.8 wt.%) and (48-50.3 wt.%) when reaction was carried out at 350 and 400\(^o\)C for 25 hours operations.

To predict cell breakage in bioprocessing it is essential to have an understanding of the cell wall mechanical properties. This project involved a study of the wall mechanical properties of individual Baker’s yeast cells (Saccharomyces cerevisiae) using compression testing by micromanipulation. An analytical model has been developed to describe the compression of a single yeast cell between flat parallel surfaces. Such cells were considered to be thin walled, liquid filled, spheres. Because yeast cells can be compressed at high deformation rates, time dependent effects such as water loss during compression and visco-elasticity of the cell wall could be and were neglected in the model. As in previously published work, a linear elastic constitutive equation was assumed for the material of the cell walls. However, yeast compression to failure requires large deformations, leading to high wall strains, and new model equations appropriate to such high strains were developed. It was shown that the preferred model, based on work-conjugate Kirchhoff stresses and Hencky strains, fitted Baker’s yeast compression data well up to cell failure. This agreement validated the modelling approach, which might also be useful in characterising the material properties of the walls of other cells and microcapsules. Using the analytical model, the effects of compression speed on the elastic modulus obtained by fitting numerical simulations to experimental compression data was investigated. It was found that above a compression speed of approximately 45 µms\(^{-1}\) the estimated elastic modulus was essentially unchanged. By using a compression speed of 68 µms\(^{-1}\) it could be assumed that water loss during compression was negligible. It was then possible to treat the initial stretch ratio and elastic modulus as adjustable parameters within the numerical simulation. In addition to this, as the numerical simulations fitted experimental data well up to the point of cell rupture, it was possible to extract cell wall failure criteria. This study has given mean cell wall properties for late stationary phase Baker’s yeast of: elastic modulus 185 ± 15 MPa, initial stretch ratio 1.039 ± 0.006, circumferential stress at failure 115 ± 5 MPa, circumferential strain at failure of 0.46 ± 0.03, and strain energy per unit volume at failure of 30 ± 3 MPa. Following this, the effect on the intrinsic material properties of treating Baker’s yeast with dithiothreitol (DTT) was investigated. DTT has the effect on Baker’s yeast cells of breaking the disulphide bonds in the cell wall releasing invertase into the suspending solution. It was found that this did not affect the intrinsic material properties or failure criteria. In addition to this, Baker’s yeast cells were mechanically perturbed by sonication and the resulting intrinsic material properties investigated. The surface modulus was found to decrease with increased sonication time while the surface strain energy at failure remained constant. However, it was not possible to determine the extent of damage to each individual cell, preventing explicit conclusions from being reached.

In this work, size-selected molybdenum disulfide (MoS\(_2\)) nanoclusters were produced using a magnetron sputter source and time-of-flight mass filter. Magnetron sputtering is a common industrial method for preparation of MoS\(_2\) thin films. The combination of this technology with accurate size control allows us to produce, in high vacuum, lab-scale quantities of size-selected clusters. The strong spatial confinement effects in MoS\(_2\) suggests that such control will modify the catalytic properties. This method also has potential to enhance MoS\(_2\) performance in areas such as hydrodesulfurisation, intercalation batteries and tribology; as well as elucidating the dynamics of compound formation in the gas-phase. Structural properties of these MoS\(_2\) clusters are studied using aberration-corrected STEM. The optimum catalytic size range of 1-5nm has not previously been studied in detail for gas phase synthesis. This work bridges the gap in the cluster beam literature between small, few atom clusters and the production of large MoS\(_2\) fullerenes and monolayers. It has been found that MoS\(_2\) clusters display a characteristic layered structure down to the smallest studied cluster, 50 units of MoS\(_2\). Growth of clusters is indicative of anisotropic growth from the reactive edge sites, proceeds by subsequent addition of van der Waals bound layers and finally coalescence of smaller units in the case of large clusters. The electrocatalytic properties of these clusters are explored by cyclic voltammetry and show good activity for the Hydrogen Evolution Reaction despite the presence of surface oxides. The reaction current normalised matches to loading matches some of the best catalysts produced to date.