How an Australian startup is saving the Earth through a novel sustainable process. Drew Turney digs into the detail.

A pioneering group of Canberra chemical engineers is putting a hefty round of funding into the recycling science of tomorrow, and it might spell the end of one of our biggest environmental headaches.

We know about microplastics in the oceans. We’ve given up plastic shopping bags and drinking straws and we separate rubbish and recycling every week when we put the bins out.

Would it surprise you to learn it’s not nearly enough? It might be time not just for doing more of what we’re already doing but a new approach altogether.

There are 8.3 billion tonnes of plastic waste in the world, and only about 10% of the plastic we discard is recyclable simply because of its chemical properties.

There’s simply no way to recycle polymer plastics in textiles, for instance, and Professor Colin Jackson (who we’ll hear more from later) calls the amount of textile waste ‘massive’. “Clear plastic bottles. We can recycle them pretty well but that’s about it,” he adds.

Even among the material we can recycle, we seldom get more than a handful of new generations out of it, after which it’s burnt for energy (releasing more greenhouse gases) or buried in dumps – and that’s without accounting for the CO2 we pump into the atmosphere when we manufacture it in the first place.

When it comes to plastic we’re not really recycling, we’re just delaying landfill.

If we’re serious about reducing plastic waste we need to change the way we make, use and discard it, and infinite recycling might be the best idea around right now.

The circle of life

Recycling company Samsara Eco, where Jackson is the Chief Science Officer, is determined to halt the production of new plastic in its tracks. It wants to reclaim and endlessly reuse the plastic we already have using synthetic enzymes which break it down to constituent parts and let us remake it into new plastic far more sustainably than traditional recycling.

Jackson had been running a protein engineering and design lab at the Australian National University, engineering synthetic enzymes, a field with wide industrial applications including breaking down pesticides, therapeutic proteins in medicines and more.

One day in 2020, two of his lab students, bioinformatician Matt Spence and protein researcher Vanessa Vongsouthi approached Jackson with an exciting scientific paper about an enzyme that could break down plastics.

Company founder Paul Riley had already been developing the business case, and Samsara Eco was born. Late last year it raised $54m, including funding from Woolworth’s venture capital and retail funding body W23.

“It’s like building a building with recycled bricks,” is how Jackson explains circular recycling. “We knock it down and use the bricks to make another building. You’re taking a bottle and breaking it down to its molecular building blocks.”

The first key piece is the polymer, a chemical containing a large number of repeating molecules. As well as the basis for biological materials like DNA, the polymer is the perfect building block for plastics. Those smaller repeating molecules are called ‘monomers’ and in plastics, they’re manufactured chemically using fossil fuels.

Recycling polymers is a scattershot affair. “Reform it five or six times and you start to get real quality issues,” Jackson says. “It involves high temperatures and every time it goes through that you get more side products and the quality deteriorates.”

The next lynchpin is the enzyme, a chemical that catalyses chemical reactions. You might know them as the messenger proteins in biological cells, but it’s possible to make synthetic enzymes that do the same job in industrial processes.

Just one is degrading the polymers in plastics down to constituent monomers. To stretch the above building metaphor further, current recycling technology means you might be able to isolate a fireplace hearth you can reinstall somewhere else, but you can’t take it back to the individual bricks to make into whatever you need.

Made to measure

The inspiration for Samsara Eco’s technology came from a 2016 Japanese study where scientists discovered a bacteria called Ideonella sakaiensis at a bottle recycling facility in Osaka that metabolised PET plastic.

“Our enzymes are related to that one, but they’re all designed using a machine learning design algorithm. They’re unlike anything you see in nature but they’re certainly inspired by nature,” Jackson says.

A crucial attribute in the process is in only taking the building blocks back so far. If a plastic is eaten by a biological organism that does the same thing it will be remade into carbon dioxide, and releasing all the greenhouse gas locked up in that 8.3 billion tons of plastic waste is obviously a terrible idea.

But Samsara Eco’s process takes plastics back to their monomer molecules – particles big enough to retain their CO2 rather than release it. In theory, it means we can endlessly remake plastics and keep the carbon used in their manufacture sequestered indefinitely.

But while it sounds like a miracle solution, there’s still work to be done – there are plastics and there are plastics, and they all need different enzymes applied. Soft plastics (anything you can scrunch into a ball in your hand)  and coloured materials are hard to recycle, and as mentioned, there’s currently no recycling technology that works with textile polymers.

But it’s even more complicated. The enzymes created to attack different forms is fast and efficient, but Samsara Eco has its work cut out for it because of what Jackson calls the ‘mixed ball’ problem.

Plenty of applications merge more than one type of plastic together in layers, often with other materials like foils or aluminium as well. Traditional recycling involves heating and reforming plastic, but you can’t do that if it contains a layer of metal (or most other materials), rendering an entire class of products unrecyclable altogether.

But if Samsara Eco keeps at it, Jackson and colleagues can develop an enzyme for each layer of material, letting them loose to break down only specific targets. “As the technology develops and you get more of a loop, the materials that are more recyclable become more popular and cheaper and it’ll make more economic sense,” he says.

The circular economy

But there’s a difference between an exciting environmental academic study and systemic change. As Jackson stresses more than once, circular recycling will only come when it benefits (or at least doesn’t hurt) household and corporate incomes. He states the company’s goal as being; ‘[making] sure the quality is as good as virgin plastic and doing it economically.’

But Samsara Eco (and the rest of us) are facing a harder problem than the science or manufacture of plastic-eating enzymes; culture.

Jackson points to Europe, where government regulations around recycling are robust, and Japan, where doing so is seen as a social good that benefits everyone. He goes on to mention a few US states that don’t recycle at all.

He thinks both carrots and sticks are needed. “Bottle collections – where you get 10c for each empty – is having a really good effect in Australia and incentivising people to recycle,” he says. “Community-minded messaging about recycling works, and then you can also mandate behaviours, especially when it comes to industry.”

CEO Paul Riley agrees. “Legislation will help jumpstart the supply chain cycle and help move us towards our climate change goals,” he says. “We have the ideas, talent and drive to solve the problem, but we need government support and corresponding investment to achieve the goals set out in climate roadmaps.”

But sustainability has had a rocky road since the early days of the environmental movement. The RedCycle scandal – where soft plastics taken to supermarkets around the country were stacked in warehouses instead of processed – is just the latest regulatory/commercial failure that’s made many consumers wonder why we bother at all.

“I worry that it damaged the credibility of the research in Australia and people might be more cynical about it,” Jackson laments. “But you need the technology and you need the goodwill.”

Samsara Eco is working hard on the technology. The rest is up to us…