Doctoral Training Partnerships: a range of postgraduate training is funded by the Research Councils. For information on current funding routes, see the common terminology at https://www.ukri.org/apply-for-funding/how-we-fund-studentships/. Training grants may be to one organisation or to a consortia of research organisations. This portal will show the lead organisation only.

Aim: To develop new approaches to study micro-localisation and dynamic ion flux in biofilms using fluorescent nanosensors. Introduction: Bacterial biofilms are implicated in the onset of many oral diseases such as caries, gingivitis and halitosis. These biofilms, often referred to as dental plaque, are attached to both oral hard and soft tissues and whilst daily brushing of the teeth removes a significant amount of these biofilms, their rapid re-growth and the presence of undisturbed biofilm located in areas not amenable to brushing means that plaque is ubiquitous. A typical dental plaque consists of a multi-species biofilm containing both aerobic and anaerobic species. Acidophiles such as Streptococcus mutans metabolise fermentable sugars to acids, particularly lactic acid. The pH of these plaques is therefore variable on diet and it has been repeatedly shown that the pH of plaque falls rapidly after consumption of sugar, rising after a period of time as the acid is neutralised by salivary buffers. During this low-pH period the enamel surface of the tooth is vulnerable to dissolution of the calcium-containing mineral hydroxyapatite that makes up 95% of the enamel composition. Repeated pH challenge of the enamel eventually leads to the formation of a carious lesion and ultimately cavitation of the tooth, requiring dentist-intervention (drilling and filling). The process of enamel dissolution though is dependent on many factors other than pH, including the concentration of calcium and fluoride ions within the biofilm. Other ions, such as zinc, which is present in many types of toothpaste, may also have an impact on both plaque ecology and enamel dissolution. Current models of oral plaques are useful tools that have been used to understand the concentrations of the critical ions (Zn2+, H+, F-, and Ca2+) in plaque in total, although a detailed understanding of both the transport kinetics under dynamic conditions and micro-localisation of the ions within the biofilm have yet to be determined. It is generally believed that the plaque is able to act as a reservoir for these ions, although the form and location of the ions within the plaque has yet to be determined. Research Programme: In this work we will incorporate fluorescent chemo-sensing nanoparticles (PEBBLE nanosensors) within model oral biofilms grown on enamel and map, in real-time, concentration profiles of the critical ions. PEBBLEs sensitive to zinc, calcium and pH have already been prepared and a fluoride-sensitive PEBBLE will be developed as part of this work. Ion-concentrations will be mapped both in static biofilms, and in dynamic biofilms, where glucose will be used to generate acid in situ, mimicking a real carious challenge. Further the effects of added fluoride and zinc ions on the biofilm calcium concentration will be examined under a variety of conditions, including investigation of approaches that increase plaque-fluoride uptake. It is believed that this work will contribute greatly towards the understanding of ion-transport through biofilms in general, and in oral biofilms in particular. This work should also enable a more thorough understanding of the caries process and how oral healthcare actives can influence caries development.

The EPSRC CDT in Integrated Catalysis (iCAT) will train students in process-engineering, chemical catalysis, and biological catalysis, connecting these disciplines in a way that will transform the way molecules are made. Traditionally, PhD students are trained in either chemocatalysis (using chemical catalysts such as metal salts) or biocatalysis (using enzymes), but very rarely both, a situation that is no longer tenable given the demands of industry to rapidly produce new products based on chemical synthesis. Graduate engineers and scientists entering the chemical industry now need to have the skills and agility to work across a far broader base of catalysis - iCAT will meet this challenge by training the next generation of interdisciplinary scientists and engineers who are comfortable working in both bio and chemo catalysis regimes, and can exploit their synergies for the discovery and production of molecules essential to society. iCAT features world-leading chemistry and engineering groups advancing the state-of-the-art in bio and chemo catalysis, with an outstanding track record in PhD training. The CDT will be managed by a strong and experienced team with guidance from a distinguished membership of an International Advisory Group. The rich portfolio of interdisciplinary CDT projects will feature blue-sky research blended in with more problem-solving studies across scientific themes such as supramolecular-assisted catalysis using molecular machines, directed evolution and biosynthetic engineering for synthesis, and process integration of chemo and bio-catalysis for sustainable synthesis. The iCAT training structure has been co-developed with industry end-users to create a state-of-the-art training centre at the University of Manchester, equipping PhD students with the skills and industrial experience needed to develop new catalytic processes that meet the stringent standards of a future sustainable chemicals industry in the UK. This chemical industry is world-class and a crucial industrial sector for the UK, providing significant numbers of jobs and creating wealth (currently contributing £15 billion of added value each year to our economy). The industry relies first and foremost on skilled researchers with the ability to design and build, using catalysis, molecules with well-defined properties to produce the drugs, agrochemicals, polymers, speciality chemicals of the future. iCAT will deliver this new breed of scientist / engineer that the UK requires, involving industry in the design and provision of training, and dovetailing with other EPSRC-, University-, and Industry-led initiatives in the research landscape.

The amide bond is arguably the most significant in pharmaceutical chemistry, featuring in a host of important everyday pharmaceuticals for the treatment of ulcers, high cholesterol and pathogenic infections by bacteria and viruses. It is vital therefore that there exist atom efficient and sustainable green chemical methods for the synthesis of pharmaceutical amides. However, industrial synthetic methods for the preparation of amides suffer from the use of complex or hazardous reagents to accomplish their chemistry and generate a large amount of waste. Because of this lack of efficiency, industrial synthetic chemists are increasingly turning towards 'biocatalysis' or 'Industrial Biotechnology' as the preferred method of synthesising molecules for pharmaceutical production. Biocatalysts, such as enzyme or microbes, typically achieve the synthesis of chemical bonds with excellent atom efficiency and selectivity, and Nature is also expert at synthesising amide bonds, which are the major bonds that hold the structure of proteins together. Until now however, biocatalysts for the formation of amide bonds have received little attention for industrial application, even though such enzyme reactions feature at the top of the list for many chemists looking for biocatalytic solutions to synthetic problems. This is because biocatalytic methods for amide bond formation in Nature, while efficient, are often complex, and difficult to apply out of their natural context. A recently discovered group of enzymes, which we have called amide bond synthetases (ABSs), offers new and unexplored promise for biocatalytic amide bond formation, as their reaction chemistry is comparatively simple, and also because the kind of amide bonds that they form, are much more closely related to molecules of real pharmaceutical interest than has previously been the case. In this project, which is a collaboration between biochemists and synthetic chemists at York, and in association with GSK and also the University of Freiburg, we propose to thoroughly investigate the synthetic potential of the new ABS enzymes. First we will define the potential and limitations of the natural enzymes using a mixture of synthetic chemistry and biocatalysis. We will then use the recently-determined structure of the ABS enzyme McbA to engineer the enzyme, expanding its potential for the catalysis of the synthesis of a much wider range of pharmaceutically relevant molecules. We will also use contemporary protein evolution techniques to adapt the enzymes to act on alternative substrates that are of interest to industrial collaborators. We will also apply new techniques in enzyme cofactor recycling to allow us to scale up the amide bond forming reactions, and also immobilise the enzymes in order to establish a flow biocatalysis system for amide synthesis. Finally, we will combine ABSs with other enzymes to create 'cascades' for the synthesis of amides from readily available alcohol and amine substrates. Together, the project will establish a new frontier in biocatalytic amide bond formation with a view to more sustainable chemical processes for the industrial synthesis of pharmaceuticals.

Doctoral Training Partnerships: a range of postgraduate training is funded by the Research Councils. For information on current funding routes, see the common terminology at www.rcuk.ac.uk/StudentshipTerminology. Training grants may be to one organisation or to a consortia of research organisations. This portal will show the lead organisation only.