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Is compostable plastic really compostable? As you might know, we have a serious plastic problem.
The production of a plastic bottle that holds 1 litre of water requires 100 times more water to create.
Then, all bottled water requires another 17 million barrels of oil each year.
In comparison, that’s more than the fuel required to fill up the tanks of one million cars, each year.
Moreover, while the production is an issue, the recycling of that resulting plastic is an even bigger problem.
How Much Plastic Ends Up In Landfills?
According to the EPA, Americans recycle less than 10 per cent of the plastics they’ve used.
Only some plastics are suitable for low-quality recycling, and that’s about 20 per cent.
The remaining 80 per cent ends up in landfills where the plastic needs 1,000+ years to decompose.
Furthermore, as plastic decompose, poisons compounds leak into the environment and can cause several health issues to animals and people, including reproductive problems and cancer.
Is Compostable Plastic The Solution to Plastic Pollution?
Scientists have created a mutant bacterial enzyme that breaks down plastic in hours.
Moreover, the resulting material is good enough to be converted into plastics of high-quality.
To date, the existing plastic recycling technology only produces low quality plastics.
For that, these plastics can only be used in certain items: sweaters, sleeping bags, jacket insulation and even carpets.
Most plastic is made from petroleum-based compounds which require enormous amounts of fossil fuels to produce and transport.
The most popular one is polyethene terephthalate (PET) and this enzyme knows how to degrade it.
The enzyme was first discovered eight years ago, in a compost heap of leaves.
Studies show that it is able to degrade the plastic bottles to basic chemical elements.
Once degraded, those elements can be reprocessed into new, food-grade plastic.
How Important Is Compostable Plastic?
Well, just when you think that Americans alone throw away 35 billion empty water bottles a year….it makes sense.
Behind the discovery of the new enzyme is a French company called Carbios.
According to their spokesman, they should achieve industrial-scale recycling within five years.
Carbios has partnered with large companies using plastic such as L’Oréal, Pepsi, Coca-Cola, and Nestle to advance further the research and development of the new compound.
So How Does Compostable Plastic work?
The team, led by Professor Alain Marty from the Université de Toulouse and Science Director at Carbios, began by analysing 100,000 microorganisms for their suitability.
In the batch, there was the leaf compost bug. The original compost enzyme research dated back to 2012 and had been all but forgotten.
“After two years of the work of 20 scientists, we obtained this incredible enzyme able to deconstruct 90 per cent of PET in less than 10 hours,” said Professor Alain Marty from the Université de Toulouse, and leader of the Carbios team.
The scientists analysed the bacteria and introduced mutations to improve its ability to break down the PET plastic.
All enzymes described in the scientific literature were tested. Also, thousands of microorganisms from PET polluted environments were screened.
From all, Enzyme LCC, described in a publication in 2012, appeared to be a good starting point to optimise the performance in terms of thermostability and activity.
But where previous attempts to repurpose PETs that had had chemicals added to give specific characteristics such as rigidity or flexibility and colour had been less than successful, this procedure was successful.
Can Any Plastic Be Degraded?
This new process can depolymerise any PET – transparent, coloured, opaque, amorphous as well as crystalline, fibres – into any PET product.
“We did not see any inhibition of the enzyme by colourants, pigments, Isophthalic acid, carbon black, titanium dioxide, other polymers,” Marty said.
The team managed to make the process stable at 72°C (161.6°F), close to the perfect temperature for fast degradation.
They used the modified enzyme to break down a tonne of waste plastic bottles, which were 90 per cent degraded within 10 hours.
Compostable Plastic Is Close, But Still Not There
Right now, there are some parts of that process that require further improvement.
For example, plastic bottles must be shredded and heated before the new enzyme is mixed in.
These two extra processes will make recycled PET plastic products more expensive than so-called virgin plastic.
However, Marty said that due to a shortage of supply, existing, lower-quality recycled plastic anyway sells at a premium.
“We will start building a demonstration plant in a few weeks. This plant will start-up in Q2 2021 to generate products and license our process by the end of 2022,” he completed.
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