Turning low value pulp and paper side streams into bio-based Nylon precursors

Nylon 66, a lightweight polyamide of high resilience for various industrial applications, is currently synthesized from adipic acid obtained from non-renewable resources and with significant release of the greenhouse gas nitrous oxide.

The present project proposes to upgrade existing low value streams from the Swedish pulp and paper industry to produce bio-based adipic acid. Streams under consideration include black liquor, lignoboost but also waste water from the bleaching pulp process.

The project is expected to increase forest resource efficiency while providing a sustainable alternative for Nylon 66 production.To reach this goal, we will evaluate a previously developed biocatalyst (an engineered Pseudomonas putida bacterium) for its capacity to produce muconic acid from lignin-derived monomers and optimize the production process by investigating the effect of several parameters: required level of aeration, possible substrate and/or product inhibition, need for co-substrate, effect of pH, etc.

In parallel we will identify enzymes that enable the one-step conversion of muconic acid to adipic acid, using metagenome library screening or site-directed enzyme engineering and the help of a biosensor for adipic acid detection.

The most efficient enzymes will be introduced in our biocatalyst to enable direct production of adipic acid from lignin monomers, and the engineered biocatalyst will be evaluated for adipic acid production from side-streams of the Kraft pulp process.