Sustainable circular economies are intrinsically tied to renewable resource flows, where vast quantities need to be available at a central point of consumption. Abundant, renewable carbon feedstocks such as the second-generation lignocellulosic based biomass are available to create net zero carbon circular economies. The hexoses and pentoses in this feedstock can be efficiently valorised using biological routes, however lignin which comprises of about 40% of the lignocellulosic biomass is recalcitrant in nature and lacks efficient biocatalysts for converting the lignin monomers into value added products. Systems metabolic engineering has demonstrated its capability in designing and developing industrially potential microbial strains producing products from renewable feedstocks. Within this multidisciplinary project, combining mutational studies based on targeted engineering of enzymes, integrating the mutated enzymes into the host and imposing selection pressure by evolutionary based selection will be used to select cell factories with enhanced lignin monomer (vanillin, guaiacol, phenol and cresol) utilisation, increased tolerance, enhanced product secretion etc. The project will screen multi-functional Cytochrome P450 enzymes which catalyses conversion of lignin monomers, into intermediates facilitating microbial uptake. Certain amino acid targets will be selected based on molecular dynamic simulations for enhanced substrate specificity and catalytic efficiency. Mutations will be implemented via site directed mutagenesis and in vitro enzyme assays will be performed to analyse the effect of the mutations. Selected mutated enzymes will be implemented into the host bacterial strains, Cupriavidus necator and Pseudomonas putida and evolved for enhanced substrate utilisation and tolerance in a continuous evolutionary fermentation strategy. Mixotrophic gas fermentation process will be developed to create a net carbon zero emission fermentation process with efficient titre, yield, and productivity metrics. At the end of the process, we will be able to select bacterial strains with increased tolerance and utilisation capacity of the lignin derivatives with an optimised process producing value-added products. A comparative study will be performed between P.putida and C.necator in converting the lignin monomers to value-added products. This will open doors towards diverting the carbon from the lignin derivatives towards value-added products efficiently creating a sustainable biomanufacturing route, making use of the lignin fraction in the lignocellulosic feedstocks. The project brings multidisciplinary areas like synthetic biology and fermentation technology in creating sustainable lignin valorisation routes.
Eligibility and How to Apply:
Please note eligibility requirement:
- Academic excellence of the proposed student i.e. 2:1 (or equivalent GPA from non-UK universities [preference for 1st class honours]); or a Masters (preference for Merit or above); or APEL evidence of substantial practitioner achievement.
- Appropriate IELTS score, if required.
- Applicants cannot apply for this funding if currently engaged in Doctoral study at Northumbria or elsewhere.
For further details of how to apply, entry requirements and the application form, see
Please note: All applications must include a covering letter (up to 1000 words maximum) including why you are interested in this PhD, a summary of the relevant experience you can bring to this project and of your understanding of this subject area with relevant references (beyond the information already provided in the advert). Applications that do not include the advert reference (e.g. MRDF22/…) will not be considered.
Deadline for applications: 18 February 2022
Start Date: 1 October 2022
Northumbria University takes pride in, and values, the quality and diversity of our staff and students. We welcome applications from all members of the community.
Informal enquiries to Dr Rajesh Bommareddy ([Email Address Removed]).