THE next time we peel prawns at the dinner table, the shells will probably go straight into the bin. We rarely give them another thought. Yet those discarded shells contain a natural material that researchers are exploring as a possible ingredient for biodegradable plastics.
At Universiti Malaya’s Faculty of Engineering, researchers have investigated how prawn shell waste can be converted into chitosan, a natural biopolymer, and used to produce biodegradable plastic films.
The work offers a practical example of the circular economy: turning something typically treated as waste into a useful resource.
This matters because Malaysia faces two waste challenges at once. Food waste makes up a substantial share of municipal solid waste, while plastics continue to accumulate in landfills and the environment.
The seafood industry also generates large amounts of biological waste, including prawn shells that have relatively little value once the edible portions have been removed.
Those shells, however, contain chitin, a naturally occurring substance that can be processed into chitosan.
Chitosan has attracted growing scientific interest because it is biodegradable, biocompatible and versatile, with potential applications ranging from food packaging and agriculture to biomedical and environmental technologies.
In our study, chitosan was extracted from discarded prawn shells through a series of chemical treatments before being combined with starch to produce thin bioplastic films using a solution-casting process.
But producing something that resembles plastic is only part of the challenge. If the goal is to develop a more environmentally friendly material, we also need to understand what happens after it is discarded.
To test this, the researchers buried the bioplastic films in soil and monitored them over four weeks.
By the third week, visible changes had begun to appear. The films became smaller, their colour changed and their texture started to deteriorate. By the fourth week, substantial degradation was evident.
The findings show that discarded prawn shells can be transformed into chitosan and used to produce chitosan-starch films capable of degrading under soil burial conditions.
The significance lies not simply in creating another type of bioplastic, but in connecting two environmental problems that are often treated separately.
Waste from one industry could potentially become a raw material for another.
There is, of course, still a considerable distance between producing a promising material in the laboratory and replacing the plastics we use every day.
Any commercially viable bioplastic must meet demanding requirements for strength, durability, moisture resistance, safety, cost and large-scale manufacturing.
Further research is therefore needed before materials derived from prawn shells become practical alternatives for specific applications.
Even so, studies like this encourage us to rethink what we consider waste. Prawn shells may seem to have reached the end of their usefulness once a meal is finished, but their chemical components may still have value.
That is the broader lesson of the circular economy. Solving our waste problem does not always begin with finding somewhere else to put what we throw away.
Sometimes it begins by asking whether what we discard could become the starting point for something new. ‒ Sept 11, 2026
The author is an Associate Professor at the Department of Mechanical Engineering, Faculty of Engineering, Universiti Malaya.
The views expressed are solely of the author and do not necessarily reflect those of Focus Malaysia.
Image: Pexels/Mark Stebnicki
