Analysing compostable plastics

Are compostable plastics really what they say on the packet? Study honours in plant science and experience one of the first opportunities to test a new fully compostable type of plastic.

We are drowning in a sea of plastic, causing serious concerns about the long term effects of the presence of such huge amounts of pollutants in our environments. One recent trend has been the appearance of single use packaging that is advertised as being biodegradeable or compostable.

Eco shopping bag by ASHFAQ ALI from Pixabay

Many consumers are either confused abut what this means or accept these claims at face value, never really asking just what these types of labels mean. One such biodegradeable plastic, called polylactic acid or PLA is appearing more and more - it is identified by the number 7 in the recycling symbol - and is very often advertised as being compostable. It is compostable - but what the public mostly do not realise it that this can occur only under specific laboratory conditions. If you put it in landfill or bury it in the garden it will take many years to disappear and it is not clear if it turns into harmful microplastics in the process. 

University of Adelaide scientists are working with a company who are producing fully compostable plastics, some of the first in the world, made from combining waste plant materials and a special binder. These plastics are likely to break down far more rapidly in the environment but to prove it this project involves testing just how long they take to break down in a range of situations, alongside similar packaging made of PLA.

The process will also be studied at the microscopic scale. Do either of these plastic types make microplastics along the way? How do they break down? Do they affect the microbes in the soil around them when they are buried? Would this be beneficial in the environment? Do fully compostable plastics made of different plant waste materials (think straw, rice seed husks, sugarcane bagasse) behave differently?

All these questions and more can be tackled in this exciting honours project, which provides one of the first opportunities to test these novel fully compostable plastics in the Australian environment.

Professor Rachel Burton


Professor Rachel Burton

Co-supervisors: James Cowley

Research area: Plant science, School of Agriculture, Food and Wine

Recommended honours enrolment: Honours in Plant Science

Tagged in Honours projects - Plant science, Honours projects - Agricultural science, Honours projects - Food and Nutrition Science, Honours projects - Ecology and environmental science, Honours projects - Science innovation, Honours projects - Rachel Burton, Honours projects - James Cowley