Let's talk about bio-plastics / with Petra Innemanová
Michael Londesborough: My guest today is Dr. Petra Innemanová, a research and development scientist at the Charles University Faculty of Natural Sciences and a company named Dekonta. She studies environmental microbiology, waste and bioplastics. The prefix “bio” makes me think of something organic or something biologically degradable. What’s hiding under the term bioplastic?
Petra Innemanová: The term bioplastic is a bit misleading because it includes approximately 300 types of substances with various characteristics. There are two motives for bioplastic development. One of them is the substitution of non-renewable resources, such as petroleum, with renewable ones- raw materials that can be “grown on a field”. For example, polyethylene or polyethylene terephthalate can be replaced with identical materials with the prefix bio. However, in this instance the prefix bio doesn’t mean that nature is can process the material. We shouldn’t get the impression that we can throw a bio-PET bottle into the woods and nature will take care of it. At the end of their lifecycle these materials need to go in a yellow container for plastic recycling.
PI: The current annual production makes up about 0.6 percent of total plastic production. Increasing their production could, however, compete with growing crops. Question is if we want that.
ML: What other kinds of bioplastics exist?
PI: Another kind are materials, biopolymers, originating from renewable sources through natural processes. Here the second motive for bioplastic development comes into play- end of life biodegradation. These materials are developed to decompose at the end of their lifecycle, preferably without remains, so that they don’t end up as waste in our oceans.
ML: Can you name a couple of the most important bio/bioplastics?
PI: Thermoplastic starches such as polylactic acid belong here. Materials produced from bacterial strains with a polyproxy-alkanolate base are also very promising.
ML: How long does it take for these bioplastics to decompose? Can we put them in the compost or do they require specialized conditions?
PI: It’s important to say that the name bioplastic doesn’t automatically mean something is decomposable. We learned that with the first group. Even here there’s no guarantee of 100% decomposability. It depends on product shape and the environment it ends up in. Suitable conditions are found, for example, in industrial composting plants which, among other things, reach very high temperatures. On the contrary, if the product ends up somewhere low in nutrients for the bacterial strain, decomposition will take longer.
ML: So under the right conditions, these plastics decompose easily. Does that mean that by using them we could solve the current plastic crisis?
PI: There are certainly suitable candidates that could help. There is also one more kind of bioplastics- materials which are bio only at the end of the lifecycle. They originate from a non-renewable petroleum source, but are made to be biodegradable. They’re materials with the acronym PBS, for example polyethylene succinate, PVAP and so on. Those are also biodegradable so they belong in the bioplastic group as well.
ML: Are they degradable by bacteria or UV light?
PI: These should be biologically degradable by bacteria. Plastics with a shortened lifespan, sometimes also mistakenly categorized as bioplastics, are called oxodegradable. These are conventional plastics with a pro-oxidant additive. When exposed to UV light, increased temperatures and dampness, they undergo what is referred to as chemo-hydrolitic decomposition. The producers of these plastics declare that these small fragments are easily degradable through natural processes. That hasn’t proven to be true. On the contrary, they’ve been proven as a source of microplastics. Their production has slowed down significantly.
Not even bioplastics that should be biodegradable, such as PBS, always fulfill their producers’ promises. When we exposed allegedly one hundred percent compostable foil to field conditions for eight months, it only decomposed by about ten percent. Tests for material conditions occur in conditions that don’t necessarily exist in the real environment.
ML: According to you, bioplastics offer opportunities, but aren’t a broadly applicable solution. We can’t simply substitute synthetic plastics with easily degradable bio/bioplastics. The research isn’t expansive enough yet and we don’t know the environmental effects of the particles which remain after decomposition. Are there situations in which applying these innovations would bring us specific advantages?
PI: I see only certain bio/bioplastics are promising for helping to solve the plastic crisis. For example thermoplastic starches can be produced from agricultural waste. If production of these materials increased, however, raw materials from waste would be insufficient and production of these plastics would start competing with crop production. According to experts, polyhydroxy alkalates, biopolymers produced from waste bacteria, are the most promising. Its production is bio-technological and occurs in a cultivated medium. The bacteria processes waste materials, such as used frying oil or leftovers from first generation biofuel production. Israeli researchers have even verified highly effective production of feeding these bacteria with lysate from seaweed. However, the created biomass has to be separated from the cultivation medium. The process of polymer extraction is very challenging and for that reason the price is not competitive yet.
ML: Ok, so that’s price. But are the final product properties sufficient to satisfy market demand?
PI: It depends. There are very promising materials among these biopolymers, polyhydroxy alkanolates. Polyhydroxyvutyrate or polyhydroxyvalerate in particulare are very promising materials whose properties and temperature resistance are comparable with, for example, polyethylene. It’s not identical and cannot be substituted across the spectrum, but we could certainly find specific situations for their application, for example in single use plastic packaging.
ML: Can we start using such polymers in practice already?
PI: I would beware of overly hasty solutions, though I realize there is no time to waste, the crisis is truly culminating. Whether or not bioplastics assert themselves on the market, we need to decrease the production and consumption of single use plastics right away. There are ways to support such change, for example by adding fees for every little plastic baggy, like we already do with plastic shopping bags. A consumer always has the option of bringing their own baggy or paying extra for the luxury of a single use package. We should certainly start there. One way is through legislative measures…
ML: Those don’t exist yet?
PI: Some packaging and waste laws do exist, but their enforcement is nearly nonexistent. Packaging needs to fulfill more requirements than just protection and manufacturers can always find a reason for it to be oversized. I see more hope in working with the public. Everyone needs to start with themselves. We should start adding education about low waste, responsible treatment of packaging and so on.
ML: Should we support bioplastics through subsidies or let the natural flow of the market decide?
PI: I’m not an economist, but I don’t think it’s an appropriate solution. The tax payer would end up paying and supporting bioplastics this way wouldn’t be educational because it would lead to lower prices and the feeling that there’s no need to limit ourselves. Furthermore, before introducing these materials onto the market we have to prepare the waste management to be able to handle them.
ML: So if we were to introduce bio/bioplastics in bulk, the waste management system couldn’t handle it.
PI: At this point it’d be more of a problem than a solution. If we increased bioplastic marketshare today, their presence in yellow recycling bins would go up too. The average consumer or recycling plant employee won’t differentiate them from regular plastics at first glance. They would then devalue the material intended for recycling and we would have a problem with meting recycling goals from the European Union.
Today, if a consumer throws a bioplastic product into a brown container, neither compost plant nor biofuel station owners want that waste because the material isn’t always hundred percent degradable even in their facilities. They can do more harm than good. First we need some kind of rule for certification from a responsible authority that the materials are decomposable, even outside of industrial composting plants. They also need to be easily identifiable, for example based on color.
ML: Dr. Innemanová, I wish you great success in your research and hope that this interview contributes to this important debate with the public so that we understand what bioplastics actually are and how they can serve us. Thank you for coming by and I wish you a pleasant rest of the day.
PI: Thank you for the invite.