Bio-plastics – a less harmful alternative?

We are confronted with it every day: Plastic. To protect the environment from this harmful material, people are quick to reach for the alternative made of bio-plastics. After all, these “plastic” bags can apparently be devalued in a more environmentally friendly way together with the organic waste in the compost or in the organic waste garbage can. But this does not always work, because the material is not always as organic as it seems.

Bio-plastics are so-called biodegradable plastics. In other words, they are still plastics, but they are much more degradable than classic plastics. The materials can be divided into two categories: biobased plastics and biodegradable plastics. But more on the examples in a moment. According to the Bund für Umwelt und Naturschutz Deutschland e.V. (BUND), bio-plastics can be produced and made biodegradable in three ways:

The first option is plastics made from renewable raw materials such as corn starch or lactic acid. These are degraded by biological processes and are considered bio-based plastics. The second option is the production of petroleum-based plastics. Because this type of plastic is made with special chemicals to break down with the help of bacteria, sunlight and water, it is not completely biodegradable. This means that it takes at least 12 weeks to decompose – and then only up to 90%, because biodegradable plastic can only call itself “compostable” if it decomposes into 90% of the smallest particles (smaller than 2 millimetres) within a maximum of 90 days under industrial conditions. Only then is it considered a biodegradable plastic. Similarly, the third option involves so-called mixed polymers. This kind of plastic combines the two before mentioned approaches.
And the WWF adds another category: the biobased but non-biodegradable plastics (WWF).

Consequently, there is a confusion of definitions and possibilities as to what can and cannot be bio-plastics. And this is precisely where one of the problems lies: there is no uniform definition. For example, only one component of the plastic can be biologically labeled and the entire product can be called a bio-plastic.

The term “biodegradable plastics,” on the other hand, is defined. According to the EU standard EN 13432 or EN 14995, these materials must be able to decompose to 90% into water, carbon dioxide and soil humus within 12 weeks in a so-called industrial composting process. That sounds good at first, but it is still too slow for normal compost or biowaste. That is why in some regions of Germany, biodegradable plastics are not allowed to be disposed of in biowaste. Bio-plastics must go into the residual waste.

Strange, after all, the materials are degradable and even biodegradable. But what does that actually mean in concrete terms? According to the definition of the German Institute for Standardization (DIN), standard 16208 states the following: “Biodegradability comprises the property of a substance to be degraded by microorganisms in the presence of atmospheric oxygen to carbon dioxide, water, biomass and minerals, and in the absence of air to carbon dioxide, methane, biomass and minerals, whereby no time period is defined.”

However, biodegradable and degradable are not to be confused with each other: the former describes decomposition into components that only occur in nature – carbon dioxide and water. The latter, on the other hand, refers to the decomposition or breakdown of larger pieces of plastic into environmentally harmful microplastics.

To alleviate some of the confusion, consumers can look for the certificates suggested by WWF for bioplastic products: RSB (Roundtable on Sustainable Biomaterials) or ISCC PLUS (International Sustainability and Carbon Certification) with the addition of “GMO-free.” This at least helps to classify whether it is necessarily a bio-plastic product (WWF).


Whether trash bags, plastic cutlery, detergent bottles or drinking bottles – we encounter these specially produced bioplastics in many life situations. In 2018, about 2.27 tons of bio-based and biodegradable plastic were produced, according to European Bioplastics. By comparison, 335 million tons of classic plastic were produced in 2016. Europe accounts for 11.6% of the production of bio-based and biodegradable plastics.

But why are plastic bags made from corn starch, for example, not the most sustainable option? Corn, after all, is a renewable raw material that does not poison the soil the way chemicals do. But even renewable raw materials have to grow before they can be used. And growing a raw material – corn, for example – for a plastic bag, only to eventually throw it away to decompose, is biological, but not sustainable. With each new cycle of growth, use and degradation, production requires water, energy and other resources.
In addition, although classic plastics produced from mineral oil or other fossil fuels emit more CO2 emissions than comparatively bio-based plastics, the latter require a significantly larger proportion of agricultural land. This means that cultivation can become competition for food supplies or even lead to deforestation.

But what is the alternative? Sure, jute bags and no plastic at all – organic or not. But is there no hope at all for the organic plastic industry? Yes, there is: However, according to the WWF, the renewable raw materials would have to be sustainably obtained and consistently managed in a cycle. This means that what has once been sustainably produced or grown must then be collected, processed and recycled in a system adapted to the material – and no longer simply thrown away. Here, for example, the tried-and-tested deposit system with a current return rate of 94% could be used. Products made from bio-based plastics could also be taken back and recycled in this way. Clear labeling of “biobased,” “biodegradable,” or even both is essential here.

In addition, the European Commission is working to bring clarity to the opaque situation of bioplastics: The aim is to regulate which plastics are considered biodegradable or even compostable, i.e. degradable through additives, and how disposal can work. The Commission has also set itself the goal of precisely defining the terms “biobased” and “biodegradable” in order to make everyday life easier for consumers at the organic waste garbage can and in the supermarket.

– by Maximilian Immer

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