Predicting and Quantifying the Biodegradability of biopolymers

This project aims to develop a new framework for predicting and quantifying the biodegradability of biopolymers with greater accuracy than current testing allows.

There is increasing interest in the use of biopolymers such as chitin, cellulose and starch as alternatives to the synthetic polymers derived from fossil fuel as feedstock for global industrial and consumer products. It is envisaged that switching from fossil fuels to natural polymers, which are produced by many living organisms such as plants, can help to negate climate change impacts of chemical production.

In recent years, the consumer chemical and products industry has increased its production of synthetic polymers, with at least 140 million tons now being produced every year (Siracusa, 2019). These polymers are used in everything from plastics to cosmetics and pharmaceuticals as well as personal hygiene products (Shah et al., 2008). With the human population still growing and set to reach 9.7 billion by 2100 (UN, 2019), demand for such products is likely to increase over the next few decades. It is becoming increasingly important therefore to assess the impact of these polymers on the natural environment, both during their production and after their disposal. At present most polymers in use are produced through the fractional distillation of crude oil, a process that is associated with the release of greenhouse gases thereby contributing to climate change. Additionally, some of these polymers may have adverse effects on wildlife when they enter the natural marine or terrestrial environments, damaging biodiversity as a result.

It is hoped that chemical products produced using these biopolymers will be more biodegradable than the current synthetic ones and so will have little impact on the stability of ecosystems or biodiversity in general. However, little is known about how biodegradable these polymers are, and there remains some uncertainty as how to test their biodegradability. The many regulatory biodegradation tests that exist are more than 30 years old and were designed to assess small, low molecular weight chemicals and their applicability for assessing larger, more complex polymers has not adequately been assessed. In addition, there is a need to develop screening tools that allow for rapid assessment of the likelihood of polymer biodegradation in order to guide upstream innovation.
Limitations to existing tests highlight a research gap in our understanding of how to measure biodegradation in polymers. The switch to biopolymers has great potential to ameliorate the twin issues of climate change and biodiversity loss however, it is crucial that their biodegradability can be predicted and quantified before they are disposed at scale into the environment.

This will involve using bioinformatics tools to identify enzymatic pathways of interest for biodegrading polymers and the range of enzymes capable of catalysing these pathways. Microbial ecology techniques will then be used to determine the relative abundance of microbes that produce these enzymes in the relevant environments (i.e. where the polymers will end up after disposal). Adaptations will also be made to some existing biodegradation tests so these can be combined to form a cohesive framework that can reliably predict and quantify the biodegradability of polymers.