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Australians are one of the world's biggest producers of e-waste.
Governments and environmentalists are working together to try and cut down on the multi-million-dollar burden this puts on our recycling system, and scientists may have just made a potentially promising discovery.
What is e-waste?
E-waste covers anything from an old television set, computer monitors past their prime and any electronic in between.
They can't be recycled by traditional methods, because they're made up of metals, glass, plastics and chemicals that can be toxic to both people and the environment if they aren't properly broken down properly.
That means it has to go to special drop-off points where it can be disposed of properly, and ideally repurposed.
While the Australian government has promised to develop a mandatory scheme that will send e-waste to be broken down properly, it's still awhile off.
Why is this a problem?
According to the Global E-Waste Statistics Partnership, the average Australian produced about 21.6kg of e-waste in 2022.
The Department of Climate Change, Energy, the Environment and Water predicted Australians could be sending 657,000 tonnes of potentially toxic e-waste to the tip by 2030.
And the current recycling methods aren't perfect.
Unfortunately, the mix of metals and chemicals in e-waste can be difficult to separate, and as a result can cause something called "contaminated sludge".
So scientists have started looking at other solutions.
What does Vegemite have to do with this?
A team of scientists in Austria recently had an idea: yeast.
Spent brewer's yeast is a waste product from brewing beer, and famously, is a key ingredient in Australia's favourite sandwich spread Vegemite.
The hypothesis the scientists were working with was simple: brewer's yeast is readily available, a natural waste product, and a natural "biosorbent".
It's not a new idea: waste biomass like brewer's yeast has been used in the past to treat wastewater, but applying it to e-waste was a new challenge.
Scientist and author Dr Klemens Kremser helped conduct the study, and said the results had swung their way.
"In order to achieve a selective metal recovery, investigated spent brewer´s yeast as effective and environmentally friendly biosorbent," he said.
How does it work?
According to the paper, published by Frontiers in Bioengineering and Biotechnology, scientists took 20 litres of spent brewing yeast, and went through the process of testing it on different metals.
Through a process of adsorption — a phenomenon where particles or molecules bind to a top layer of a solid — metals were pulled from the yeast surface by acid treatment.
Scientists were able to separate out aluminium, copper and zinc.
They were able to conclude:
"Using an industrial waste biomass such as spent brewer’s yeast kept the costs of this process low," the paper reads.
"Moreover, spent brewer’s yeast proved to be an excellent candidate for the selective metal recovery."
What does this mean for the future?
Here's the kicker: the yeast wasn't done yet.
Scientists were able to recycle it between uses — up to five times in order to recover different types of metal.
Dr Kremser said this was a significant breakthrough for recycling e-waste safely and effectively.
"Nature provides us with solutions for daily problems," he said.
"Using waste to treat and upgrade other types of waste reduces the need of primary resources, thus helping to reduce the environmental impact of improper e-waste recycling.
["Spent brewer's yeast] is cheap, easily available and safe."
Dr Kremser said there was still work to be done in the space, including scaling up the experiment on a larger and less controlled scale to see how it plays out.