8. Metabolic engineering of Pseudomonas putida for the biological valorization of Kraft lignin

Lignin is a complex aromatic heteropolymer that composes plant cell walls providing rigidity and protection against pathogens. It is one of the most abundant polymers on earth after cellulose, with an average of 130 million tons of this polymer being produced only by the Kraft pulping industry per year. Therefore, lignin is a low-cost abundant source of aromatic compounds that can be applied in the food, textile, plastic, and chemical industry, opening possibilities for a circular bioeconomy. However, lignin is recalcitrant for chemical and enzymatic degradations and requires elaborated strategies for its conversion to added-value chemicals.

In this project, we investigate a framework for lignin bioconversion by the bacteria Pseudomonas putida to produce nitrogenous bulk chemicals as an alternative to fossil fuels-based compounds. To achieve this, we explore different enzymes to generate new-to-nature biochemical routes, enabling the bioconversion of lignin-derived compounds. NMR metabolomics is used to detect undesired side reactions or key steps for the metabolic engineering of P. putida. Design of Experiments (DoE) method will be applied to optimize gene expression and growth conditions parameters for achieving higher yields of the target compounds, providing new routes for producing nitrogenous bulk chemicals.