Recombinant bacteria for producing plastics from plant biomass waste

A Pseudomonas putida strain engineered through synthetic biology capable of producing 5-carboxymethylpyridine-2-carboxylic acid (2,5-CPDCA) from lignin-derived monomers. 2,5-CPDCA is an analog of homoterephthalic acid, used for synthesizing plastic polyesters.

Market need: 99% of commercial plastics come from non-renewable fossil resources. A transition toward more sustainable production and consumption models is necessary, reducing the use of fossil fuels while simultaneously promoting waste reutilization. Agri-food waste contains large amounts of lignocellulose, whose valorization is hindered by lignin, a recalcitrant polymer obtained after the use of the cellulosic fraction in the paper and food industries. It is essential to develop efficient biocatalysts as sustainable alternatives for bioplastic production that are also capable of valorizing waste such as lignin.

Proposed solution: A genetically modified Pseudomonas putida KT2440 strain has been developed to express a heterologous biosynthetic pathway for producing 2,5-CPDCA from lignin-derived aromatic monomers (e.g., homovanillic acid (HVA) or 4-hydroxyphenylacetic acid (4-HPA)). The biotransformation process is based on bacterial fermentations and resting cell systems, achieving conversion efficiencies of 74% (from 4-HPA) and 40% (from HVA). The biosynthesis of 2,5-CPDCA offers great potential for valorizing plant waste while simultaneously enabling the production of novel plastic materials with improved properties.

Competitive advantages

It is the first biological method described for the production of 2,5-CPDCA.
The process achieves a conversion efficiency of up to 74% from lignin-derived aromatic monomers.
The production of 2,5-CPDCA is environmentally friendly, since—unlike the synthesis of terephthalates—it does not rely on petrochemical sources.
The synthesis from plant waste promotes the circular economy.