Numerous products in our everyday lives are based on fossil raw materials, including plastics and fuels produced from crude oil, as well as polymers for textile fibres and medicines. However, using fossil raw materials such as crude oil, coal and gas generates high CO₂ emissions and harms the climate. As today’s economy is largely based on fossil raw materials, a re-think is needed. In Germany, alternatives to fossil raw materials are already being sought in many areas with the aim of creating sustainable economic growth. The bioeconomy relies on process innovations that contribute to sustainability goals. These can be based both on technologies using biogenic raw and residual materials as starting substrate and on biological processes that exploit the metabolic performance of living organisms, such as microorganisms, bacteria or algae, or parts of them.

Packaging is also often made from fossil resources. It is used to protect packaged goods and, in the food sector for example, make food edible for longer. It is needed in logistics for transportation and must meet additional requirements in the area of medical and pharmaceutical products. Packaging is made of various plastics, paper, cardboard, composites, metals, glass and wood. But what happens to packaging after use?

Within the framework of a circular economy, the ultimate goal is to reuse, process and recycle existing materials and products for as long as possible. Reusable plastic and glass bottles are widely used in the beverage sector. However, disposable beverage packaging is also widely used. In 2017, the recycling rate of disposable PET bottles for which a deposit is charged was estimated at around 90 percent.¹ However, overall recycling rates for packaging were significantly lower. While the recycling rates for glass (84.4%), paper/cardboard (87.6%) and steel (92.2%) were quite high, the recycling rates for plastics (49.7%) increased over the previous year, but were still significantly lower than for other materials. Wood packaging (25.8 %) also had a relatively low recycling rate compared to other materials.² In recent years, the packaging industry has repeatedly been in the spotlight of government and society, especially as regards environmental protection, because the increasing amount of improperly disposed packaging waste (littering) not only pollutes the local environment, but also the sea and inland waters. Particularly in the case of plastics, the environmental impact in the utilisation and post-utilisation phase (littering, microplastics, etc.) outweighs the environmental impact of production. However, the amount of plastics discharged into the environment from Germany is marginal, because the collection of packaging waste generally works quite well. In 2017, a total of 18.7 million tonnes of packaging waste were generated in Germany. This is the highest quantity so far recorded, which is a sad fact in itself. Food, beverages and pet food account for around 62.3% of packaging used by individual end consumers.² With 226.5 kg of packaging waste per capita in 2017, Germany registered an increase in packaging waste of 3.8% compared to the previous year. One solution for reducing waste is the regional bottle return system in the beverage sector, but some packaging cannot be reused, especially in the food sector. If waste prevention is not a solution, recycling is the next best option. This is where the new Packaging Act that sets higher targets for recycling rates, and became law in Germany in January 2019, comes into play.³ However, before plastic packaging can even be recycled, it has to be manufactured. One alternative approach to packaging manufacture lies in the bioeconomy: sustainably produced and recyclable packaging materials made from biobased raw materials and residues from agriculture and forestry, and municipal waste, in some cases using biological production systems, are a step towards a more sustainable packaging system.

There are now processes for replacing crude oil-based plastics with biobased plastics. Various approaches are being pursued. Tecnaro GmbH, based in the Baden-Württemberg city of Ilsfeld, has been pioneering the use of innovative biobased materials since 1998. The company's lignin-based materials can already be used to replace numerous plastics, such as ABS, PE, PP, PS as well as technical plastics such as polyamides (PA6, PA6.6, PA12). It is therefore not surprising that a versatile material developed by Tecnaro, called ARBOBLEND®, is also used in the coffee industry. The biomaterial replaces aluminium or plastic from which conventional coffee capsules are made. The biobased coffee capsules are also certified biodegradable.⁴

Waiblingen-based rezemo GmbH also produces biobased coffee capsules. The start-up company uses the wood shavings that accumulate as residual material in sawmills in the Swabian Mountains. Polylactic acid (PLA) from plant starch forms the matrix for the wood composite, which is also certified biodegradable.⁵

Producing packaging from residual and municipal waste is another way to save resources. In the EU project VAMOS (Value Added Materials from Organic Waste Sugars), for example, a project consortium is working on extracting sugars from the lignocellulose fraction of domestic residual waste. One of the goals is to produce various bioplastics (thermosetting plastic and polylactic acid) from the sugars obtained in the project. Polylactic acid can be used for packaging in the non-food sector, such as cleaning and personal care products. Industrial biotechnology could help create added value from mixed waste in a way that has not yet been possible when using domestic residual waste in conventional material recycling processes. This is thanks to technology patented by the British company Fiberight. Fiberight uses a process in which enzymes hydrolyse materials with a high paper content, for example, which are separated from the organic waste, to produce sugars such as glucose, xylose and others. The organic waste is then converted into biogas. ifeu Institut für Energie- und Umweltforschung Heidelberg GmbH is the project partner responsible for assessing the sustainability of the entire value chain, including ecological, economic and social aspects. "The aim is to close the material cycle," explains Dr. Heiko Keller, project manager at ifeu. "Because this gives us the possibility of using biotechnology to recycle the fractions that consumers cannot separate according to type and which are usually contaminated. This has huge potential." At the beginning of the project, ifeu provides advice, e.g. to identify possible unexpected feedback effects, amongst other things with previous waste recycling systems, at an early stage. At a later stage, the experts conduct a quantitative analysis in the form of a life cycle assessment. Integrated sustainability assessment involves bringing together the ecological, economic and social aspects and deriving recommendations for action. The EU project involves partners from Germany, Great Britain, Ireland, Italy, Austria and Denmark.⁶

The EU project MYPACK, involving partners from France, Germany, Italy, Greece, the Netherlands and Switzerland, is also related to the development of the biobased plastic PLA, but on a different basis. The sugars for PLA are obtained from agricultural and food industry residues. Polyethylene furanoate (PEF) is another polymer being investigated by the consortium, which includes the University of Hohenheim and a number of German companies. PEF can also be obtained from food waste or food industry residues and is specifically intended to replace PET as food packaging. However, the project work packages not only include the development of innovative packaging solutions, but also cover the expectations and needs of industry and consumers.^{7, 8}

The Baden-Württemberg Ministry of the Environment, Climate Protection and the Energy Sector is calling for proposals for the "Bio Ab-Cycle" funding programme for biowaste and wastewater refineries and in 2021 will be funding biorefineries that produce and subsequently recycle raw materials from waste and wastewater. Two feasibility studies funded by the Baden-Württemberg Ministry of the Environment, Climate Protection and the Energy Sector and by the state agencies BIOPRO Baden-Württemberg GmbH and Umwelttechnik Baden-Württemberg as well as the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart have already demonstrated the basic functionality of the approaches.

In a project called Biorefinery for the Bioeconomy in Baden-Württemberg (B4B), involving the Karlsruhe Institute of Technology (KIT), the University of Hohenheim and BIOPRO Baden-Württemberg GmbH, Miscanthus biomass is broken down into a carbohydrate and a lignin fraction. In further steps, the resulting hexoses are processed to hydroxymethylfurfural (HMF), the pentoses to furfural, and bifunctional, phenolic compounds are obtained from the lignin fraction. In this project, too, ecological assessment (life cycle assessment, LCA) and cost considerations play a key part.⁹ The examples show that biorefineries that extract platform chemicals from various biobased resources or that use biological processes offer another solution for the packaging industry.

Paper, which is usually produced from wood fibres or recycled material, has long been a component of various packaging systems and has a high recycling rate. The fact that paper can also be obtained from plant-derived biogas substrates is new and this is something that is being developed in the Hahnennest Energy Park project in which the fibre-rich stems of Silphium plants are broken down using an innovative steam explosion system before being fermented in the biogas plant. While the remaining residue streams are used to produce biogas, the plant fibres are processed and used for the production of paper packaging. Scientific support for the project comes from the State Institute for Agricultural Engineering and Bioenergy at the University of Hohenheim. The Baden-Württemberg Ministry of Rural Affairs and Consumer Protection is providing 60,000 euros in funding. The plant fibres will be broken down in the steam explosion plant of OutNature GmbH, which started operating in 2020. This makes it possible to extract the natural fibres contained in Silphium plants before fermentation. Silphie Paper GmbH further processes the material into sustainable paper.¹⁰ The packaging for fruit and vegetable trays made of Silphium fibres designed by OutNature GmbH shows the potential of this material. The product was awarded the German Packaging Prize 2020 in the New Materials category.¹¹

Regardless of where it comes from, however, it is important that used packaging materials can be recycled. Recycling is already widely established for paper and cardboard. In the case of so-called drop-in plastics, which have the same chemical structures as fossil-based plastics, e.g. Bio-PET, recycling is not a problem. These plastics can be reprocessed via established recycling routes. If the chemical structure is not the same as that of conventional plastics, sorting packaging plastics is a problem. The packaging material has to be available in sufficient quantities for special PLA recycling plants, for example, to be economically viable.¹² So clearly, biobased is not an advantage per se. Even biobased packaging has to fit into the circular economy and prove its ecological worth by means of appropriate life cycle assessments and proof of chemical safety. One particular study has shown that biobased plastics are by no means less toxic than their fossil counterparts.¹³ An EU directive that bans disposable plastic articles from summer 2021 onwards shows that the manufacture of biobased packaging products cannot be the only solution. This highlights one of the challenges faced by both consumers and the industry: avoiding packaging waste. It remains to be seen whether the various new regulations will also lead to a re-think in society.