A Synthetic Biology approach for bacterial bioconversion of lignin into renewable chemicals
The major objective of this Project is to capitalise on recent developments in bacterial lignin degradation to rationally engineer efficient biocatalysts for bioconversion of lignin to specialty chemicals of interest for bioplastics manufacture. Lignin is an aromatic heteropolymer that is a component of lignocellulose in plant cell walls, and is produced industrially as a low-value by-product of pulp/paper manufacture and bioethanol production, hence there is considerable interest in the valorization of lignin via chemical or biochemical approaches, so far with limited success. At present we have limited knowledge of the metabolic pathways for bacterial lignin degradation, and their regulation, which will be addressed in this Project using lignin-degrading Pseudomonas putida KT2440, a genetically and metabolically amenable bacterium whose genome has been sequenced and whose aromatic metabolic network is the best known in bacteria. We have four specific objectives:
1) We will develop high activity biocatalysts for lignin oxidation. We will identify further members of the bacterial Dyp peroxidase and Mn superoxide dismutase families, and we will use protein engineering and directed evolution to enhance their activity.
2) We will use a systems biology approach to discover the metabolic and regulatory networks for lignin degradation in model organism P. putida KT2440, and develop a condition-specific metabolic model in this organism.
3) Using synthetic biology and systems metabolic engineering, we will re-route the metabolism of P. putida KT2440 for the production of high value chemicals.
4) Fermentation-based processes will be developed for the target bio-products in collaboration with the industrial partner, and the bio-products will be converted to polyesters for polymer testing.