The aim of the present work was to study the effects of molecular interactions between proteins upon foam quality in batch and continuous operations, and to investigate foam fractionation as a method of protein recovery from real biological feedstocks. Foam stability studies of model protein solutions acted as engineering indicators and highlighted the importance of electrostatic interactions between basic (lysozyme and cytochrome-c) and acidic proteins (BSA) upon foamability and foam stability. Batch and continuous foam operations were employed in the study of electrostatic interactions between BSA and lysozyme and their effects upon foam quality. Batch foam production at pH 8.0 strongly demonstrated the importance of molecular stoichiometry upon individual protein partition into foam. Maximal lysozyme recovery was achieved at equimolar conditions and coincided with minimal fractionation between the two proteins. Continuous foaming demonstrated that foam positive proteins such as BSA (collector) can function as mobile ion-exchangers for poor foaming agents such as lysozyme (colligend). Experimentation with real biological systems such as brewer's yeast extract indicated that complex protein systems appear to behave like single protein solutions in terms of the effects of operating parameters upon foam performance. Such behaviour was confirmed by preliminary studies with bovine heart muscle homogenate. "Dry" foams, in continuous foam processing of brewer's yeast extract, were associated with dilute feedstocks, low gas flowrate and prolonged liquid residence times. They were characterised by high protein enrichment, low recovery, enhanced protein fractionation from RNA, but suffered extensive protein precipitation. Studies of dynamic changes in foam bubbles showed that such phenomena are associated with extensive coalescence. It was concluded that, although single protein model systems can offer valuable information on foam fractionation, direct comparisons with real biological solutions should be treated with care. A need for further study on the role of protein interactions upon foaming was also identified. Finally, the currently held view of rejecting foaming as a source of protein precipitation should be reviewed and advancements in foam fractionation as a preliminary step in downstream processing should employ the development of semi-empirical predictive models.

This thesis describes efforts made towards the synthesis of a biologically stable, luminescent molecular probe, which could be used to investigate in vivo the processing of sugars by β-galactosidases. To this end, a lactose-based probe was designed, featuring a Lanthanide held within a chelate and appended to the glucosyl unit, and a proximal naphthyl moiety, attached to the galactose unit, which would function as a sensitiser for luminescence. A β-galactosidase enzyme from B. circulans was chosen to carry out the investigation. A number of novel methyl glucosides, functionalised with a naphthyl moiety at C6 of the sugar, were prepared. These were then used as glycosyl acceptors to make disaccharides (lactose analogues), with the enzyme (functioning in reverse) catalysing the glycosylation. The enzymatic reaction was optimised by varying the amount of enzyme, the reaction pH, the ratio of glycosyl acceptor to donor, the reaction temperature, concentration and solvent mixture. The optimal conditions were found to be a 0.4 M reaction solution at pH 7.0 with 20% acetonitrile, a 7:1 ratio of glycosyl acceptor to donor, 19.6 U of enzyme per mmol of acceptor, and a reaction temperature of 30°C. The resulting disaccharide products exhibited unusual regioselectivity for the β-galactosidase from B. circulans, with unexpected β(1→3) and β(1→2) glycosidic linkages being formed. In an effort to increase the efficiency of the process of identifying suitable substrates for the enzyme, a dynamic combinatorial chemistry approach was also explored. This used disulfide bonds to attach the naphthyl moiety to the methyl glucoside using linkers of different lengths. From this library, the enzyme successfully processed the novel disulfide GlcOMe-S-S-CH\(_2\)Np as a glycosyl acceptor with p-nitrophenyl galactose as the glycosyl donor. This resulted in a novel disaccharide featuring a naphthyl group attached via a disulfide bond to the glucosidic residue.

The hydrodynamics and mass transfer characteristics of a concurrent downflow contactor (CDC) are studied in this work in order to investigate the viability of this bubble column as a catalytic reactor for the hydrogenation of α,β-unsaturated aldehydes. Oxygen/water was used as the system throughout. In order to obtain reproducible results, a very effective gas-liquid separation method was conceived and developed after much trial and error work. Shutdown and deadleg gas holdup measuring methods were compared and it was found that the shutdown method is more reliable than the deadleg method. The hydrogenation of cinnamaldehyde using both in-house-prepared and commercial palladium, platinum and ruthenium catalysts was carried out in stirred tank reactors and cocurrent downflow reactors in order to study the kinetics and mass transfer characteristics and the selectivity towards the corresponding desired product, hydrocinnamaldehyde or cinnamyl alcohol. When palladium catalysts were used the desired product was hydrocinnamaldehyde. The effects of homogenous reactions, type of solvent, catalyst loading, temperature, pressure, reactant concentration and the effects of promoter or poison on the selectivity towards hydrocinnamaldehyde were investigated systematically. Aldehyde acetals were produced in polar solvents, but not in non-polar solvents. Two methods can be used to obtain hydrocinnamaldehyde selectivity without reduction of the carbonyl double bond: (1) by using non-polar solvents such as toluene; (2) by incorporating poisons or promoters into the reactant solution or onto the surface of the catalysts. 97% selectivity to hydrocinnamaldehyde was achieved. The effects of the solvent, temperature, pressure, catalyst loading, promoters, and reactants concentration on the kinetics were studied and the following reaction kinetics are proposed for the hydrogenation of cinnamaldehyde over non-modified palladium/charcoal catalysts in propan-2-ol and in toluene: Ra = kC\(_{Cat}\)C\(_{H2}\)C\(^0_{CAL}\) The apparent activation energy varies with themperature range in propan-2-ol and is 65\(\pm\)5 kJ.mol\(^{-1}\) in toluene.

The synthesis and characterisation of a variety of zeolites and aluminosilicates has been achieved using hydrothermal methods and solid state calcinations. The system using elemental aluminium, silica and sodium hydroxide solution as starting materials was explored using hydrothermal methods (200°C), and reactions conditions were optimised for the formation of analcime, sodalite, zeolite A and faujasite. All materials were characterised using powder x-ray diffraction. The thermal conversion of zeolite A and sodium chloride into sodalite has been studied using combined TGA and DTA analysis and time resolved powder neutron diffraction heating up to 800°C. It was found that the thermal conversion occurred at 550°C and no intermediate phases were observed during this transition. The synthesis and characterisation of a range of reversibly photochromic sodalites has been achieved via thermal processing of zeolite A with sodium sulphate and a variety of group I metal salts. All of the sodalites adopt the space group P-43n and were characterised by powder neutron diffraction and Rietveld refinement. Structural refinements show that substitutions at non-framework sites alter the framework bond distances of the sodalite and the observed optical property. Different colours of reversible photochromism have been observed and tailored by use of different salts in the synthesis, and trends between structure and optical property have been examined. Synthesis of the anhydrous zeolite type phase K2Al2Si3O10(KCl) with edingtonite topology has been achieved using a high temperature, high pressure reaction (600°C, 7000psi). Rietveld refinement of powder x-ray diffraction in the space group P-421m was performed. The tetragonal unit cell was found to have refined lattice parameters of a = 9.7488 and c = 6.4879. Structural considerations have been examined as to the inaccessibility of the analogous rubidium phase. Several different methods for formation of zeolite films have been investigated, and the properties of these films compared with view to thermal processing of the films, or forming the basis of a high throughput solid state array. Films were characterised using powder x-ray diffraction and scanning electron microscopy. Thermal processing of the zeolite films was performed to collapse the zeolite into a reversibly photochromic sodalite.

The research presented in this thesis explores the design and fabrication of microstructured and switchable biological surfaces, which may have potential applications of nanobiotechnology. The thesis focuses on the fabrication of biological surfaces which can be controlled via external stimuli. Chapter 1 - Introduction to Nanobiotechnology - presents an introduction to the background of this research including the role of self-assembled monolayers (SAMs) in nanobiotechnology, microstructure fabrication techniques, stimuli responsive surfaces and cell migration. Chapter 2 - Surface characterization techniques - presents surface characterization techniques employed throughout this research. Chapter 3 - Study of Arp2/3 complex activity in filopodia of spreading cells using patterned biological surfaces - presents the fabrication and characterization of patterned biological (fibronectin) surfaces using patterning technology (microcontact printing) and several surface analytical techniques. This study explores the role of filopodia in the spreading of Mouse Embryonic fibroblast (MEF) cells and the function of Arp2/3 complex in this process. The results demonstrated that filopodia, produced by MEF cells interacted with the patterned fibronectin surface and guided lamellipodia protrusion. Arp2/3 complex, which is absent on the filopodia adhesion site, does not facilitate in the adhesion of filopodia on the fibronectin surface. Chapter 4 - Tuning specific biomolecular interactions using electro-switchable oligopeptide surfaces - presents the fabrication of responsive surfaces that rely on electro-switchable peptides to control biomolecular interactions on gold surfaces. This system is based upon the conformational switching of positively charged oligolysine peptides that are tethered to a gold surface. The bioactive molecular moieties (biotin) terminates on the oligolysines can be reversibly exposed (bio-active state) or concealed (bio-inactive state) on demand, as a function of surface potential. Chapter 5 - Experimental procedures, protocols and synthesis - describes the experimental techniques used during the investigations performed throughout the work described in this thesis. Experimental protocols and data analysis by various equipment are described.