Ambi street
Woman from India
Even in India, I think there are a bunch of companies that have started offering especially garbage bags or products made, you know, out of bioplastic – I think it’s a great initiative. I’m not so sure what goes behind it, as in, you know, how, I mean, how less polluting is it to the environment, do you still need to take it to the landfill, or…so I’m still very unclear on the bioplastics to be very honest. I do use it, but I’m not sure about the technologies behind it.
Music – Plink by Dorian Roy
Street Collage
Anja (outside)
I’m making a plastic podcast, and this episode is on bioplastics, and I wanted to find out about what people think about bioplastics.
Woman from Vietnam
I think bioplastic is a good way to decrease the pollution in our world today. But I don’t know if the price is, like, affordable.
Man from Australia
Unfortunately, in this world we live in, you can’t get away from plastic. And so anything that makes it biodegradable is a much better solution.
Man from New Zealand
Bio-based and bio-degradable? I do think I know too much about the difference between those.
Woman from US
I don’t know, I guess I’m still skeptical about biodegradable plastic. Anything that’s plastic to me, I’m still thinking this is still nearly impossible, I mean…and people also have to do the right things with it. That, to me I think, is the biggest limitation. But you know, if I have a choice between biodegradable plastic and normal plastic, I’ll, you know, still take their word for it and try it out.
Anja
You’re listening to Plastisphere, the podcast on plastic, people, and the planet. I’m your host, Anja Krieger.
In this episode, I want to take a closer look at these new materials that seem to be popping up allover the market. Plastics that are advertised as compostable, bio-degradable or made from plants.
When I first heard about bioplastics, I thought that this is the solution to our plastic problems! But then I found out that it’s much more complicated. In 2012, I followed a bioplastic bag to the factory and talked to producers and scientists here in Germany. Back then, all the experts told me that bioplastics are no solution for marine pollution.
But that was seven years ago, and technology is always advancing. Plastic in the ocean is now recognized as a major issue around the world, and consumers are asking for alternatives. So I think it’s time for an update. Can bioplastics solve our issues with trash? And what does “bio” even mean?
Constance Ißbrücker
There are a lot of bioplastics or materials that are called bioplastics that are not biodegradable. They are bio-based, they are made from plants, but they are not biodegradable. And this is because biodegradable depends on the chemical structure of the molecule and not by the source it is made of.
Anja
A couple of weeks ago, I met with Constance Ißbrücker. She’s a chemist and Head of Environmental Affairs at European Bioplastics. That’s the industry association here on the continent. At this point, they represent a tiny niche market. Bioplastics contribute less than one percent to overall plastics production. But the market is growing.
Constance Ißbrücker
And it’s really dominated by so-called drop-in materials, like for example bio-based polyethylene or bio-based PET. And these materials are just more or less equivalent to their fossil-based counterparts, so you can use them in the same applications, you can make bio-based PET bottles, for example, or you can produce a bio-based PE packaging.
Anja
These plastics are really convenient for the industry. Producers and recyclers can just drop them into their existing infrastructure without having to buy new machines. That’s why they are called drop-in materials. They are made on the basis of plants, like sugarcane or corn, but are chemically identical with conventional plastics made from oil or gas. More than half of all bioplastics on the market are just bio-based, not biodegradable. And that means that they cause the same kind of pollution as normal plastics. So what’s the point in producing them, if they are not designed to break down in the environment?
Constance Ißbrücker
I mean the biggest benefit is, of course, very simply said, it’s made from renewable resources. That means we get independent from oil or other fossil resources. And this has a very good impact on the whole carbon footprint, you save carbon dioxide, because a plant takes up carbon dioxide from the atmosphere and this carbon dioxide is then stored in your bio-based product. And the product maybe can be recycled, when it cannot be recycled any longer, it will be most probably incinerated and then the carbon dioxide is set free – but all in all this is a quite positive or neutral carbon dioxide balance.
Music – Blue Dot Sessions – Heliotrope
Anja
I wondered if people know about the drop-in bioplastics that do not biodegrade. So I went out to the streets of Berlin.
Collage
Anja (on the street)
Did you know that there are bioplastics that are biobased, made from natural materials, but they are not biodegradable. Did you know that?
Women from UK
No…I didn’t know that.
Anja
And they are chemically identical to conventional plastics, like they are the same, they are PET, or PP or PE. Do you know that?
Woman from Germany
No, I didn’t know that. Why are they entitled to be named bioplastics then?
Anja
They are made from a renewable source, and so they save fossil fuels.
Woman
I see, I see. Well, but still, I think, probably we then have to define better how to certify bioplastics, because one important thing,… of course, how you produce it is important, but also, even more important is how it does desintegrate, and if it is not desintegrating, it shouldn’t be called bioplastic.
Man from New Zealand
I imagine bio-based is a lot more natural and would degrade not instantaneously, but within a couple of months.
Woman from the US
Isn’t it, I mean, one is how it’s made and one is how it’s thrown away. So, if something’s biobased that doesn’t necessarily mean that it’s gonna be able to go away. And same for the other way around, right? Can’t you make things that would go away easy, but aren’t made from renewable stuff? Yeah, I don’t know.
Anja
That’s true. There are plastics derived from fossil sources that are in fact biodegradable. Just as there are plastics made from plants that do not biodegrade. Welcome to the complicated world of bioplastics!
And growing plants to make plastic might cause other issues. Critics say this puts pressure on land needed to grow food. Bioplastic farms could threaten biodiversity and lead to an increase in monoculture cropping, pesticide and water use. The industry is trying to tackle this by switching to algae and waste materials as a feedstock. But they still have a long way to go.
So plastics made from plants do not necessarily have a better footprint. And over 60 percent of them do not bio-degrade, which means they will cause the same pollution as normal plastics. But what about the biodegradable ones. Can they help us tackle the problem? To find out more about biopolymers, I called up a chemist.
Music – Building the Sledge by Blue Dot Sessions
Frederik Wurm
I believe biodegradable plastics are a great idea. However, it’s difficult to make, let’s say, a good biodegradable polymer. And I believe there’s no one-fits-all solution.
Anja
Frederik Wurm is a scientist at the Max Planck Institute for Polymer Research in the German city of Mainz. He and his colleagues work on designing molecules for materials which include biodegradable plastics. The lab is developing substitutes for polyethylene as well as polymers for medical applications and mulch films for agriculture.
Frederik Wurm
We need different properties of plastics in different applications. Sometimes it’s lifetime, sometimes it’s where they are used, if it’s a humid area or if it’s a very dry area. If you would like to pack a liquid, you probably need a different property than if you would pack something which is very dry, like flour or so.
Anja
When it comes to biodegradable plastics, the challenge for chemists like Frederik Wurm is to try to develop a material that lives not one, but two lives. The first one, with all the necessary and desired functions for that product – and the second, as food for microorganisms. Cause that’s what biodegradation means.
Frederik Wurm
…and depending on the kind and the amount of microorganisms this can take long or can be a fast process. So thinking about sea water where we have a lot of plastic waste currently, sea water is typically not so warm. So most of the sea is cold and there are also not so many microorganisms around. That’s why many of the classical, what people call biodegradable, they do not degrade in seawater, or they take ages to degrade.
Anja
The sun, waves, or marine animals can break up plastics into smaller pieces. But that’s not enough for the material to really enter back into the natural cycle. That’s just simple degradation, and it will lead to yet more microplastics. For true bio-degradation, we need organisms that can attack and completely break down the long molecule chains of the plastic.
Frederik Wurm
…so making the long chains into shorter chains, or into fragments of these chains, and in the end, in the ideal case, they can also use that to build it up into their own organism and grow – basically food for them. And this is the process we call bioassimilation, and in the end mineralization, where the material is really used in processes of the organism.
Music – Tidal Foam by Blue Dot Sessions
Anja
Microbes produce enzymes, and some of them can act like knives and cut biodegradable plastic. But not every microorganism has the right knife for every type of polymer. So we need the right microbe with the right enzyme for the right plastic. If the microbe can break the plastic into small enough chunks, it can ingest them. And then, not unlike what happens when we eat, the microbe can use the food to gain energy and weight. In the process, it produces water, CO2 or methane. Frederik Wurm carries out a series of tests in the lab to see if a plastic biodegrades. He starts by exposing it to harsh acids or bases. If that doesn’t work it’s clearly not biodegradable. If it does, he sees if enzymes can do the job.
Frederik Wurm
And the final test is typically field testing that I, for example, bury this in a soil or put this in seawater or put this in a compost or in activated sludge from the sewage plant, and I see if these organisms can degrade the material.
Music – Heliotrope by Blue Dot Sessions
Collage
Anja (on the street)
What would you expect, what kinds of qualities should this plastic have?
Woman from Germany
It should be able to disintegrate very quickly, very quickly meaning within a year.
Man from Australia
Well, it should happen immediately, and…but it all depends on the application.
Man from New Zealand
When I hear biodegradable plastic, I expect it’s still going to take, you know, a couple of years to degrade. I think normal plastic is 500 years? So when somebody tells me, biodegradable, I expect maybe, five, ten years. Still take a long time, but a lot better than what we have now.
Anja
Even biodegradable plastics can take years to completely break down in the environment, if they do at all. And there’s not only one kind, but many different types, which all behave in different ways in different places.
Linda Amaral-Zettler
You’re perfectly justified in being confused…! (laughs)
Anja
I called up Linda Amaral-Zettler, a microbiologist at the Royal Netherlands Institute for Sea Research. She and her team discovered the Plastisphere, the new ecosystems growing on microplastics in the ocean, which also gave name to this podcast. She’s also very much involved in the discussion on biodegradable plastics. Linda explained to me how crucial it is to consider the time it takes for plastic to completely break down.
Linda Amaral-Zettler
…because everything’s biodegradable over thousands of years, at some point, everything’s biodegradable, right? But really, we want things that are going to be biodegradable and compostable in a reasonable timeframe. And I think that, you know, that is an important caveat, is, when people think about how long things take to degrade and biodegrade in the environment, there needs to be a concept of time attached to the sort of definition.
Anja
Linda is part of a committee that deals with environmentally degradable plastics at ASTM International, the former American Society for Testing and Materials. ASTM is one of the organizations which develop voluntary standards for the industry. To get one of their labels, producers have to show that their plastic fullfills the criteria to biodegrade in a certain setting. Like, for example, in industrial composting, with hot and humid compost heaps. But when it comes to the open environment, especially the ocean, creating a standard gets truly tricky.
Linda Amaral-Zettler
One of the biggest challenges and discussions that this community is having is whether the standards need to be reflective, completely reflective of the marine environment or whether it’s acceptable to sort of have a standard that tells us something about sort of the optimal scenario, where under warmer temperatures and sunlight and conditions where there’s the most sort of favorable conditions for biodegradation – so the complete breakdown of plastic into molecules, simple molecules that organisms can directly use completely – whether, you know, it makes sense to just do those under conditions where you can see the complete end product being total use and incorporation or CO2 respiration.
Music – Building the Sledge by Blue Dot Sessions
Anja
For the marine environment, there is no standard for biodegradable plastics yet to clearly pass or fail. And the question is whether there ever can be one. Because the conditions in different parts of the oceans are not the same. They can be warmer or colder, lighter or darker, and more or less salty – and each ecosystem is inhabited by different organisms, including the microbes which might or might not be able to break down the plastics.
At Hydra, a private research institute with a station on the Italian island of Elba, marine biologist Christian Lott and his team test biodegradable plastics. They immerse them in different ocean environments, for example the Mediterranean to the Arctic.
Christian Lott
Or we do it in the mangroves in the tropics where you have mosquitoes, you have to dig holes in the sand or in the mud, with spiders and snakes around you. So it’s it’s challenging sometimes but this is the work we love.
Anja
It’s an adventurous task, and one that needs a lot of expertise. Christian and his partner have developed a special testing frame, so that their plastic samples don’t get swept away with the currents underwater. Their field tests can run for years. With their method, they can safely retrieve and analyze their samples. Most of the plastics tested at Hydra have already been shown to biodegrade under marine conditions in the lab.
Christian Lott
But the critique is that these laboratory tests – that are also found in American and European and ISO standards – are optimized and do not necessarily reflect the conditions in the wild, in the nature, in the rivers, in soil, or in the ocean. And then we as marine biologists come into play and do these tests in an open system, under the water, at the beach, in the mangroves, in a coral reef, in the sand and observe how these materials degrade – knowing that in lab condition they would be eaten by bacteria.
Anja
There is one type of biodegradable plastic that seems to be almost impossible to digest for marine microbes – PLA or polylactic acid. It’s a quite popular material.
Christian Lott
The structure of PLA, the chemical structure is so, let’s say, dense that it’s really hard to be attacked by bacteria or fungi – this only works at higher temperature or with strong acids, so these are the conditions you find in industrial compost with pure PLA. But you can modify – and this is the art of bioplastics manufacturing – you can blend, for instance, PLA with other substances to make them more prone to hydrolysis, which is the initial chemical process, and then to the degradation of the polymer itself by bacteria for instance or fungi.
Anja
Pure PLA is not readily biodegradable in the ocean. But Christian and the Hydra team found that all the plastics that did biodegrade in the lab also did so in their field tests.
Christian Lott
…but you have to keep in mind that also natural materials in the wrong, let’s say, situation, conserve forever. We have fish fossils that after 300 million years still show color from polymers, natural polymers.
Anja
So we can never say for sure if any material biodegrades in the environment. It really depends on where a piece of plastic ends up on its journey through the oceans. Which is pretty impossible to predict.
Christian Lott
Some of the very well degradable materials – which by the way are produced by bacteria – which are called polyhydroxyalkanoates, they degrade in tropical environment on the sea floor in a thin foil within one to two months. But in the Mediterranean it can take ten times as much. And imagine, in the Arctic, in the ice or at ice-cold water, on in the deep sea where we have zero degrees to 4 degrees, hardly any nutrients around, bacteria will take, or will have a hard time to digest these materials.
Music – Beat by Blue Dot Sessions
Enzo Favoino
Certainly they degrade faster than traditional plastics in the marine environments. But still they take time to degrade and in the meantime if a turtle or a dolphin meets a biodegradable bag they could, you know, mistakenly consider them as food or something like that. And so this might be a problem.
Anja
Biodegradable plastics are no solution to marine pollution, says Enzo Favoino. He’s a waste management expert at the Scuola Agraria del Parco di Monza. In his country, Italy, all plastic bags have to be compostable. And the industrial composters in the country accept and process these biodegradable bags together with the food waste. In some other places, like my home country of Germany, that’s not the case.
Enzo Favoino
We have long been using compostable plastics as a tool connected to separate collection programs for organics. In Italy, there is a long tradition of using such compostable plastics in order to maximize the captures of organic waste, which in turn minimizes the percentage of organics inside residual waste, and therefore it helps us optimize the separate collection systems as a whole.
Anja
Enzo serves as the Chair of the Scientific Committee of Zero Waste Europe. He says that it is crucial to collect as much organic waste as possible to reduce the trash that goes to incinerators and landfills. The compostable plastic bags can help with that, Enzo says. They make it more convenient for people to collect their food scraps or garden waste separately – and that means that these organic materials don’t end up in the residual trash. With less organics decaying in these bins, waste management operators can come by less often to pick them up. And that in turn motivates people to collect paper, glass, plastic and metal separately – materials that can then be easily recycled. Another advantage is that less organic waste ends up on landfills and dumps. There, it can produce methane – a powerful greenhouse gas.
Enzo Favoino
It’s 21 times more powerful than carbon dioxide – and so this is the largest contribution to climate change from the waste management sector.
Anja
So the separate collection of kitchen and garden waste has two benefits for the environment: More recycling and less greenhouse gases. To this end, Enzo supports the use of compostable plastic bags. It’s a closed system: The bags are sent to industrial facilities, where they can biodegrade under controlled conditions.
And that is very different from composting at home, in a garden. Which is why Enzo does not support a standard for home compostable plastics.
Enzo Favoino
First of all, compostability in home composting systems makes no sense, whatsoever, to my opinion, because people doing home composting would not need the compostable bags, of course, because they just take the food scraps and they put them in the composting heap or in the composting bin in their backyard. But also it gets the wrong message across, because people would be mistakenly led to think that if it composts in the backyard it would compost also in the countryside, which is utterly wrong of course.
Music – Verdigris by Blue Dot Sessions
Linda Amaral-Zettler
We speak of plastic as this monolithic giant, right? We speak of plastic as if it’s one thing. But it’s not, it’s thousands of things.
Anja
Just as there are many different conventional plastics, there are different biodegradable ones. Different polymers can be mixed together in the products we buy, and what’s often added, is a whole array of chemicals. These substances can make the plastic soft or durable, transparent or colorful, or they protect it from sunlight or fire. It is the toxic potential of some of these additives and other substances from production that many people worry about. A woman from Vietnam I met on the street told me she expected bioplastics to be different.
Woman from Vietnam
I expect it will be better for the environment, and also contain less, like toxic ingredients, I believe, and their making process wouldn’t be that bad for the environment, and also they must be like strictly supervised.
Anja
This would be nice, but new research suggests otherwise.
Lisa Zimmermann
What I can tell from my research is that bioplastics are not necessarily safer than conventional plastics with regard to the toxicity of the chemical mixtures they include.
Anja
This is Lisa Zimmermann, a PhD student at the Department of Aquatic Ecotoxicology at Goethe University in Frankfurt, Germany.
Lisa Zimmermann
So there might be products which might better, there might be others which might not be necessarily be better with concerns to the toxicity of the chemicals they include, but we can’t say, okay, overall, the chemical toxicity of bioplastics is less than of conventional plastics.
Anja
Lisa was at a conference in Helsinki when we skyped. She had just presented first results from her experiments with chemical mixtures she extracted from bio-based and biodegradable plastics. One organism she worked with was a bioluminescent bacterium which can glow.
Lisa Zimmermann
And if something interferes with the metabolic activity of this bacteria, the luminescence decreases. And the more the luminescence decreases, the higher something seems to interfere with the metabolism of this organism. So that’s a measure for what we call baseline toxicity. And what I saw for example in this assay, that more than, or it was around two-thirds of all the plastic products, bioplastic products, I tested, they inhibited this bioluminescence, so they somehow seemed to interfere with the metabolism of this organism.
Music – Arourourou by Blue Dot Sessions
Anja
I often go to a farmer’s market here in my neighborhood in Berlin. Not long ago, one of the organic farmers there offered me a bag that looked like plastic. I said no, I don’t take plastic bags anymore. But he said, this isn’t plastic! Which made me really curious, so I accepted it. It was a white bag with a big green tree printed on the side, and there was a description in Polish on it. “For the sake of the environment, an oxo-degradable bag”, it translated.
Later I learned that these are conventional plastics like polyethylene. But they are mixed with metal compounds that make them fall apart faster. A report by the United Nations Environment Program says that it hasn’t been proven that oxo-plastics truly biodegrade. It is feared they might just accelerate microplastic pollution. I told Linda the story of the bag I got from the organic farmer.
Linda Amaral-Zettler
You know, it clearly is not his fault, right? I mean how can, you know, the green grocer, or the organic farmer stay on top of all this controversy? (Laughs) Right? I mean, I can barely stay on top of all this controversy. And I, you know, I’m dedicating a large part of my career to this problem. But there you have it, right? You have this scenario where people really want to embrace and do the right thing. And yet, you know, we’re being misled. How to how to confront that?
Anja
The European Union has now decided to ban oxo-degradable plastics. And there’s another kind, the so-called enzyme-mediated plastics. According to European Bioplastics, which haven’t been proven to truly biodegrade. Their industry expert told me that there have also been misuses of the accepted standards and labels. No wonder it’s so hard for us consumers to understand whether the claims we find on products are legitimate or not.
Music – Groove by Dorian Roy
Three years ago, Imogen Napper, a PhD student at University of Plymouth in the UK, collected bags in the stores that were touted as degradable or even “planet-safe”. She submerged some of them in the sea, buried others in the soil, and left some sitting out in the air. After three years, to her surprise, she found some of them still intact.
Imogen Napper
Not one of the bags could completely vanish or completely degrade in all of the environments, and particularly in the soil and the marine environment, some of the bags could still hold a full bag of shopping.
Music – Beat by Dorian Roy
Anja
During my research for this podcast, I came to believe that bioplastics might just be the most confusing material humans have ever invented. Even some of the experts told me they struggle.
So let me try to wrap this up. Bioplastics occupy a tiny market. Only two million tons are produced each year, compared with hundreds of millions of tons of conventional plastics. And half of the bioplastics are just bio-based, not biodegradable.
Whether the other half can really biodegrade, depends on the type and mixture of plastic, the environment it ends up in, and the microbes that are present there. Because they are the ones who do all the work.
There are no globally accepted standards yet to make sure bioplastics can degrade in
soil or the oceans – and some say it’s better that way. Because in the open environment, the materials we have today are no solution to plastic pollution. Could this change with new technology? I asked Frederik Wurm, the chemist.
Frederik Wurm
So there are at least academic approaches for that. So being a chemist, a synthetic chemist, you can build in many molecules triggers, for example, when you have a certain wavelength of light or maybe electricity, magnetism. There are many, many stimuli that you can install into a synthetic polymer chain. When you switch this stimulus on it will degrade. But this is… it sounds fancy and it is fancy and it’s expensive.
Anja
Unfortunately, it’s not only an issue of cost. Building molecular triggers into every material for every environment seems to be an almost impossible task. And plastic is a traveller, so we can never know where it might end up.
Constance Ißbrücker
I do not think it makes sense to make marine biodegradable packaging – and even, even if you do so, you should not label it as a marine biodegradable packaging because for consumers that would mean, ahh, I can just throw it away – it would give the wrong message.
Anja
And that leaves us with the good old low-tech solutions to plastic pollution.
Frederik Wurm
By just reducing the amounts of packaging that we have, or the types of different packaging that we have in our supermarkets we can do a lot, without developing novel materials. Just reducing it and see what is not necessary.
Anja
The bioplastics we have today might offer benefits for some applications. But they are not going to magically disappear when we are done with them. The most environmentally friendly plastic of all is still the one that we don’t use.
Music – Plink by Dorian Roy
Anja
This was the Plastisphere with Constance Ißbrücker, Frederik Wurm, Linda Amaral-Zettler, Enzo Favoino and Lisa Zimmermann. Many thanks to all experts for sharing their insights. I also thank the people who participated in my bioplastic poll on the streets of Berlin.
This episode was inspired and partly supported by Ensia, the solutions-focused nonprofit media outlet reporting on our changing planet. Learn more at E-N-S-I-A.com.
My name is Anja Krieger, and the music was composed by Dorian Roy and Blue Dot Sessions. Huge thanks to these wonderful musicians. For more tracks, visit sessions.blue.
I also thank Maren von Stockhausen for the cover art, Ines Blaesius, Stephanie Hood and Luisa Beck for feedback, as well as Sirine Rached for putting me in touch with Enzo, the awesome Twitter community for their thoughts and links, and the Max Planck Institute for the History of Science. The quote of Imogen Napper was provided by the University of Plymouth. And Marcus Anhäuser edited the German article on RiffReporter.
This podcast is an independent production. I have no staff position anywhere, and I’m funding this project mostly myself. So, any contributions would help! Go to plastisphere.earth and click “support” to help fund future episodes.
If you enjoyed this episode, please rate and review the podcast on iTunes, and share it with your friends.
Thanks for listening, I hope you’ll tune in again. Until then, bye-bye, and Tschüss – see you next time!