Plastic bottles and other plastic litter in a stream

Biodegradable plastics have emerged as a potential solution to the severe environmental problem caused by the production and disposal of traditional plastic. These plastics can be made from natural sources like plant-based materials and micro-organisms such as bacteria that can be used in a variety of industries such as packaging, construction, and healthcare. While plastic pollution remains a significant issue, biodegradable plastics and enzymatic plastic recycling offer promising alternatives.

For every human on this planet, there are 21 000 pieces of plastic in the ocean. If a legally binding global plastic treaty doesn’t come to fruition, plastic in the oceans will almost triple by 2040. And most of those pieces are tiny, and can’t be recycled. Humans produce over 300 million tons of plastic waste every year, with only 9% of it being recycled and about 19% incinerated to generate energy, according to the Organization for Economic Cooperation & Development. Traditional plastics are non-biodegradable, meaning they do not decompose naturally in the environment. Instead, they break down into microplastics that pollute our ecosystems and pose a risk to human health.

As a result, plastic waste has found its way into our oceans, forming massive garbage gyres and causing harm to marine life. The Great Pacific Garbage Patch, the largest accumulation of ocean plastic, is estimated to be twice the size of Texas. Fortunately, scientists, entrepreneurs, and companies are developing biodegradable plastics and recycling technology (using pyrolysis and enzymes) to help mitigate the plastic pollution problem.

The Promise of Plant-Based Plastics

Biodegradable plastics, also known as bioplastics, are made from renewable resources such as plant-based materials, and they can break down naturally in an industrial composting facility. They offer a more sustainable alternative to traditional plastics, reducing the amount of plastic waste that ends up in landfills or pollutes our oceans.

There are different types of bioplastics, each with its unique properties and applications. For instance, polyhydroxyalkanoates (PHAs) are produced by microorganisms such as bacteria and can be used for packaging, agriculture, and medical devices.

Polylactic acid (PLA) is another common bioplastic made from renewable sources like corn starch, which can be used for food packaging, 3D printing, and textiles.

Starch-based bioplastics made from corn or potato are used for food packaging and bags. Mushroom-based foam, made from the mycelium of mushrooms, can be used for packaging and insulation. Algae-based bioplastics are another emerging type of bioplastic, with potential applications in packaging, cosmetics, and pharmaceuticals.

At the Forefront of Bioplastics

Many companies are already using biodegradable plastics to reduce their environmental impact. For example, Dell is using mushroom-based foam for packaging to protect tech during transport. Lego has committed to using bioplastics made from sugarcane for sustainable Lego bricks.

Speaking to Earth911 on our podcast, Algenesis CEO Steve Mayfield describes how the company developed a biodegradable polyurethane foam called Soleic used in the soles of the world’s first biodegradable shoes made by sustainable shoe company Blueview Footwear.

“Soleic is made from sun oils, which means oils that come from plants. We started with algae, we still work on algae oils, because those will ultimately be the most sustainably sourced oil on the planet. But we also use non-food plant oils … we don’t use palm oil or soybean oil, but any other plant oil will work to make our material,” Mayfield said. Solei breaks down the fastest in compost, where the shoes become unrecognizable in nine months.

“In the ocean, it [disappears] at about half that speed … because the ocean’s air exchange isn’t as good as it is in a compost pile. Oceans are also missing a couple of key things that organisms need, so one of the things that we work on now is what can we add to our foams to get them to degrade faster. And iron, it turns out, is one of the key minerals missing in the ocean. So if you put iron into the foam, they actually degrade at a much quicker rate,” Mayfield explains.

Companies like Nestlé have committed to 100% recyclable or reusable packaging by 2025. They’re exploring the use of biodegradable and compostable plastics in their packaging. But when will recycling plastic become viable?

Tackling Plastic Pollution Through Recycling Technology

Recycling traditional plastics can be difficult and expensive, which is why new recycling technologies are deployed to make the process more efficient and sustainable. Earth911 spoke to Jeff Gold, CEO of Nexus Fuels, which uses molecular recycling/pyrolysis technology to break down 50 tons of plastic daily to be reused in new plastic.

Pyrolysis technology uses heat to break down plastic polymers (the chains of molecules) into smaller chains, which are condensed and cooled to form oils, waxes, and non-condensable gases like propane and ethane. Pyrolysis heats plastic without the presence of oxygen, so it doesn’t produce the toxic emissions that would otherwise result from heating plastic.

“All that material is captured … the oil and the wax products we make and ship off are then handled by a refinery where they are made into new plastic. The gas products, the ethane and propane, we capture every bit of that, because [it is] then routed back to our reactors where it is combusted and provides the heat for our process,” Jeff Gold explains.

Jeff continues, “We’ve created about 350 000 gallons of product and diverted 3 million pounds of plastics that would have normally gone to the landfill … We are taking plastics out of the environment and sequestering that carbon (it’s not going into the atmosphere) and making new plastics that can be recycled infinitely.”

Plastic Recycling Using Enzymes

Enzymatic recycling is a technology using special proteins called enzymes to break down plastic waste into smaller building blocks called monomers. Carbios, a French biotech company, has developed an enzymatic recycling technology that can recover over 95% of material from polyethylene terephthalate (PET), a common plastic used in beverage bottles and packaging.

Carbios’ technology uses enzymes that break down PET into its building blocks, which can then be used to create new products. The process is better for the environment because it does not require high temperatures or harsh chemicals, and, unlike mechanical recycling, the resulting plastic can be used repeatedly without losing its chemical coherence.

The Outlook for Circular Economy Plastics

Despite their promise, biodegradable plastics and enzymatic recycling technologies are still costly and resource-intensive to build and operate. It remains an open question whether biodegradable plastics will be as durable or versatile as traditional plastics.

While there are current economic and technological challenges associated with the production of biodegradable plastics, it is clear that there is a growing need for more sustainable packaging solutions. The recently ratified global plastic pollution treaty, which has been signed by over 170 countries, includes legally binding commitments to end plastic pollution and promote the use of more sustainable materials.

By Tokollo Matsabu

Tokollo is a sustainability advisor and writer based in Washington, D.C.