Understanding and enhancing plastics biodegrdation

Reducing the impact of plastics on our environment is an urgent task that needs new fundamental and technological solutions. Part of the solution is to develop "better" plastics,well-designed for their intended use and with appropriate end-of-life options. This will include compostable and recyclable materials made from renewable resources at a cost and performance comparable to, or even better than, current petro-based equivalents. Thus, the past few years have seen an increasing demand for bio-based and/or non-durable plastics, so-called bioplastics.
Poly(lactic acid), or PLA, is a bio-based polyester and the flagship of degradable bioplastics.
Due to its properties and long-standing development, there is an increasing demand for PLA. Its annual production is currently at ~435 kT worldwide and an expected production capacity increase of 80% is predicted by 2026. Crucially, the change in claims regarding its end of life options over the past 15 years, from being biodegradable (implying complete degradation to CO2, water and biomass in natural conditions) to industrially compostable (degradation incontrolled conditions, including temperatures above 60 degree centigrade, controlled humidity and selected microorganisms) highlight how much the degradation of PLA, and bioplastics in general, is poorly understood and requires attention.
Despite significant efforts, the biodegradation rate of PLA in industrial compost conditions remains low, reducing its acceptance in composting facilities (e.g. when PLA is used in disposable compostable packaging and collected along with mixed food waste). In home compost or soil (e.g. when deposited in the environment), PLA biodegradation is inexistent over a sustainable timeframe.
In this project, we will design bespoke polymeric additives to enhance the composting of PLA. (e.g. by promoting microorganism growth to speed up the biodegradation process). We propose, not only to develop polymeric additives, but also to combine them with newly engineered microorganisms and enzymes able to work "better" (e.g. faster, tolerant to higher temperatures) or able to lead to useful and added-values chemicals (e.g. starting blocks for new polymers, nutriments for the resulting compost).Ultimately, our proposed technologies will enhance the composting of PLA, bring new fundamental understanding to bioplastic biodegradation and will contribute to enabling their potential within a circular economy.