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Fungi eats discarded cigarette filters

Fungi Cigarette butts

What happens when an environmental charity meets a social enterprise to tackle one of the world’s most problematic waste products? You get a patented strain of fungi that has been trained to eat discarded cigarette filters.

Australian charity, No More Butts, and Melbourne-based mycologist, Fungi Solutions, have again joined forces to advance trials of the cigarette-fungi process that could see plastic cigarette filters recycled on a wide scale into products such as packaging materials or insulation panels, replacing another problematic waste stream – polystyrene.

Following various trials of the cigarette-fungi process over the past two years using butts collected in Perth, Cairns and Wollongong, No More Butts is now launching the CigCycle program to explore whether cigarette butt waste has a value.

The program involves diverting cigarette butt waste from landfill to use as a training substrate for mycelium. Or simply put, making cigarette filter waste a desirable food source for mushrooms.

According to No More Butts, approximately 4.5 trillion cigarette butts are discarded as litter worldwide every year, with Australia contributing around 8.9 billion butts to this figure, or around a third of the total number of cigarettes consumed.

No More Butts founder, Shannon Mead noted that while people often focused on cigarette butts being littered into the environment, it was important for them to also understand the impact cigarette butts had after they ended up in landfill. 

“Cigarette butts are a big issue,” explained Mead.

“Even when people do the right thing and dispose of their cigarette butts the correct way, once they hit the waste stream and end up in landfill, they begin leaching damaging pollutants like arsenic and lead into waterways and soil systems.

“It takes about 15 years for plastic cigarette filters to break down. Through the CigCycle program we want to divert this plastic waste from landfill and recover the resource.”

The new recycling economy?

Myco-cycling addresses some of the world’s hardest to treat toxic elements created from plastics and petrochemicals by transforming waste into new materials via the process of mycelium-based bioremediation.

Scientists around the world are discovering many environmental uses for fungi, including their ability to break down complex carbons in the natural world and eliminate a significant strain on the ecosystem by diverting materials from landfills, allowing reuse into other applications. This process is both cost-effective and sustainable. Once remediated, the result is a renewable by-product that can be manufactured into new products, ultimately creating a closed-loop economy. Australia’s own Fungi Solutions’ myco-cycling model is a world-first in the way it approaches circularity of waste and its pioneering approaches to pollutant remediation. Its work aligns closely with United Nations’ Sustainable Development Goal 12 – Responsible Consumption and Production – by providing a circular economy framework for diversion of organic resources from landfill to produce sustainable alternatives to single-use plastics that are fully home compostable. The circular myco-cycling model can be established wherever there is waste, requiring just 12 per cent of the energy for plastic production, with 90 per cent fewer carbon emissions to create regenerative materials that nourish the soil after use.

Mushroom meets butt

Following initial trials in 2021, Fungi Solutions observed that mushrooms could be trained to digest plastic. In the environment; fungi naturally encounter the plant component cellulose. Fungi Solutions has worked to adapt that same fungus, teaching it to digest cellulose’s synthetic cousin – the plastic known as cellulose acetate.

Fungi Solutions Founder and Head of Research & Development, Amanda Morgan, explained that fungi systems are composed of branching mycelium threads that spread gradually over the cigarette butts, while digesting cellulose acetate. The key is convincing oyster mushrooms that cigarette butts are edible.

“Fortunately, training mushrooms to digest a cigarette butt is like training a baby to eat,” explained Morgan.

“The fungi systems dismantle some toxic components in the butts and render them non-toxic. The only components that remain undigested are heavy metals such as zinc, copper and lead. 

“We are continuing research on possible methods of harvesting and utilising these metals in the quest for a perfect circular system. This would ensure that the remaining by-product of the mycelium and cigarette butt process is clean and entirely reusable.”

The fungi begin their digestive process by putting out fine webs of mycelium, with the roots spreading through the cigarette butt.

“It will branch out like a web and over time, you will see dirty butts become white mycelium as it expands trough the material to begin its digestion,” explained Morgan.

“Mushrooms excrete digestive enzymes as they move through places and break down food sources externally before bringing the nutrients into their systems.

“It’s a fascinating process to see, and since most of our stuff is grown in glass, we get to observe it.”

At the end of the process, the mushrooms will have eaten the microplastics in the cigarette butts’ filters, leaving behind a material that can be used to create other products, such as boxes to collect cigarette butts.

Next steps
Buoyed by the success of the initial trials with Fungi Solutions, No More Butts are now launching an innovative program – CigCycle.

Supported by the Circular Economy Communities Fund delivered by Sustainability Victoria under the Victorian Government’s circular economy plan, Recycling Victoria: a new economy, and in partnership with City of Melbourne, CigCycle targets Melbourne businesses wanting to bolster their sustainability credentials by disposing of their collected cigarette butt waste in a more value-added manner.

Mead hopes that through this program, businesses can assist in investigating potential uses for end-of-life cigarette butts, as well as make smokers pause long enough to consider what their cigarette butt does to the environment.

“In this free trial, we are calling on businesses that already collect cigarette butts as part of their daily operations, to collect them for us,” explained Mead.

“Program participants will be provided with all of the information and equipment necessary to ensure a limited change to existing processes.”

Morgan explained that the science behind the project shows that the process becomes more effective with each generation of mushrooms cultivated.

“Our research with No More Butts looks into the efficacy of this process and if there are any opportunities to produce a material by-product from the recycling of the butts,” said Morgan.

“Fungi Solutions is excited to be partnering with No More Butts and the City of Melbourne to create opportunities for local venues to join us in tackling the issue of cigarette waste.

“By establishing a circular collection program and diverting these materials from landfill, we can invest in remediating this toxic pollutant and creating a cleaner world.”

With more than 450 tonnes of cigarette butt waste ending up in Victorian landfill each year – making up 11 per cent of all litter in 2021 – for many years, City of Melbourne has invested in preventing cigarette butts entering the environment.

In 2017, the Council collected more than 200,000 cigarette butts each week from 367 cigarette butt bins across the city – litter that may otherwise end up being washed down drains and into the Yarra River.

Melbourne-based businesses interested in taking part in the program can register at cigcycle.com.au 

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