Politicians, industrial companies and environmental associations all agree that plastic damages the environment and should be avoided, where possible. This has prompted the entry into force of the EU plastics ban, which, from mid-2021, will prohibit the use of disposable plastic products such as cutlery, plates and single-use packaging. At the same time, an entire industry is working at full speed to develop environmentally friendly alternatives to petroleum-based materials. But not everything that claims to be “organic” is actually organic. The “bioplastics” label is not trademarked, and some materials are controversial – both in terms of their production and their disposal. Despite all the criticism, it is worth taking a closer look to determine which materials and uses are environmentally and economically sound. We also broached this subject with two experts, one from the European Bioplastics industry association and one from Hydra Marine Sciences, a marine research institute.

Conventional plastic is derived from crude oil, the extraction and disposal of which is questionable because neither of them are sustainable. We all have the images of great plastic garbage patches and perishing marine animals etched on our brains. In 2018, a plastic bag made the headlines when it was found at the depths of the ocean in the Mariana Trench. The dangers of microplastics are real, too. The best thing would therefore be to do away with plastics altogether, but this is not very feasible. Can we and do we have to stop using plastics altogether?

Various markets have been working for many years to develop alternative materials. The most well-known and the most commonplace are packaging, disposable cups and bags made from bioplastics. But intensive research is taking place in other areas as well, including in the automotive and electronics industries, to replace petroleum-based plastics with more sustainable alternatives. This presents a massive playing field. Constance Ißbrücker, an expert at the European Bioplastics industry association, admits that even she still finds the subject complex after years of research work.

Bio-based, biodegradable – ideally both

The basic definition of “bioplastics” is relatively simple. A material is classed as a bioplastic if it is either bio-based, biodegradable or both – the latter being the best option from an environmental point of view. Bio-based plastics are made, either partly or fully, from biomass sources. In other words, from plants that are rich in starch and cellulose such as corn or miscanthus, and occasionally also from oilseeds or wood. Only very few animal products have been used to date. The bacterial products polylactic acid (PLA) and polyhydroxybutyrate (PHB) are used. The list of plastics that are both bio-based and biodegradable includes PLA, polyhydroxyalkanoate (PHA) and polybutylene succinate (PBS). Contrary to widespread opinion, there are actually even some biodegradable plastics that are derived from fossil resources, such as the polymer polybutylene adipate terephthalate (PBAT). If a bioplastic is biodegradable, it means that it breaks down into nothing but CO₂, biomass and water. But its degradation depends on the ambient conditions as well. In other words, if a material biologically degrades in an industrial composting facility, this does not automatically mean that it will do the same in the soil, in lakes or in the ocean.

Bioplastics meet with a lot of resistance

In 2019, estimates made by industry experts put the global production capacity for bio-based and biodegradable plastics at around 1.95 tonnes. This is just under one percent of conventional plastics production. It may not sound like very much at first, but bioplastics are accused of creating competition with food production because cultivation of the plants used to produce them takes up farmland. The Federal Environment Agency website states that bioplastics are no less damaging to the environment than fossil plastics, and they tend to have delayed implications: “While conventional fossil-based plastics do release greater levels of climate-impacting CO₂, the environmental footprint of bio-based plastics may well cause greater acidification and eutrophication (eutrophication = enrichment with minerals and nutrients, editor’s note) and tie up a certain area of land.” There are also constant reports in the media that bio-based and biodegradable materials are not being broken down properly at the majority of composting facilities.

The scenario for use must be right

What are the reasons behind these objections, and can they be generalized? On the Chip 365 consumer portal, the Cradle to Cradle association discourages people from demonizing bioplastics altogether. “A plastic can be good if it is suitable for the use scenario, is biodegradable or can easily be retained in the technical cycle; in other words, can be recycled.” At present, there are a number of research approaches for producing biodegradable plastics from organic waste that are not suitable for any other purpose. The research being conducted by Hydra Marine Sciences, for example, is helping to establish an official method for evaluating the biodegradability of various types of plastic. It hopes that testing and identifying the ambient conditions under which a material is biodegradable will speed up the process of ascertaining whether a bioplastic is truly sustainable.

Although the institute recommends reducing our use of plastics in the first instance, it believes that a case-by-case decision should be made on whether a material can be replaced by a biodegradable alternative. Managing Director of the institute, Miriam Weber, lists a number of examples from agriculture, fishing, textiles and the automotive industry where biodegradability can be a good thing (see interview).  However, the marine biologist insists that it is not simply a case of replacing items, such as plates and cups, which from July 2021 will come under the EU-wide ban on single-use plastic products, with bioplastic alternatives. The Federal Environment Agency also advises the use of reusable products in this case. Both Miriam Weber from Hydra and Constance Ißbrücker from European Bioplastics advocate the use of biodegradable food packaging, as long as it can be disposed of alongside residual food waste in the organic waste bin.