[October 2025] Dr Melanie Walther is a junior scientist and junior research group leader at the Institute of Chemistry . She studied Business Chemistry at Kiel University, where she obtained her Bachelor's degree in 2016 and her Master's degree in 2018. In 2023, she completed her doctorate in the field of organic functional materials at the University of Bremen. This was followed by her postdoctoral phase, also in the field of organic chemistry.

One postdoc and three doctoral candidates will be conducting research under her supervision: Using green waste, hay and algae to produce completely biodegradable plastic that is suitable for medical products, car components, insulation and packaging - this is the project of a new junior research group at the University of Oldenburg. The research team led by chemist Dr Melanie Walther aims to combine ecologically sustainable and application-oriented approaches: The plan is to develop a cost-effective and at the same time energy-efficient technology that can be used to create new plastics based on polybutylene succinate (PBS), which consist of 100 per cent organic waste. The Federal Ministry of Education and Research (BMFTR) is funding the "EcoPBS" project with around 2.7 million euros.

"The work of the new junior research group aims to use plastics made from renewable raw materials to offer an industrially viable alternative to conventional plastics," says Prof Dr Ralph Bruder, President of the University of Oldenburg. "The BMFTR's funding commitment also recognises the outstanding research infrastructure of our university in this field and underlines the potential of 'EcoPBS' for an environmentally and climate-friendly circular economy."

Making bioplastics completely recyclable and competitive

PBS is similarly robust and processable as the plastics polypropylene and polyethylene. The big difference is that it is easily biodegradable. However, it has not yet been possible to produce a fully bio-based material that is completely recyclable. The manufacturing processes are also not yet suitable for the chemical industry. "For a high yield, you need microorganisms that are easy to cultivate and stable enough to survive in low-cost and low-energy processes," says business chemist Walther, explaining the research gap.

In three sub-projects, the junior research group is therefore investigating how the biological substrate in the form of garden cuttings and crop waste can ultimately be turned into bio-PBS. To do this, the researchers are first optimising the fermentation process: they are testing how well the organic material converts in a newly developed biotechnological process using various microorganisms. The speciality: The team is investigating two fermentations - acetone, butanol and ethanol as well as succinic acid fermentation.

New production processes for bioplastics

The second sub-project focusses on downstreaming, i.e. cleaning the converted material of foreign substances. The researchers want to refine the organic compound n-butanol into 1,4-butanediol - a bivalent alcohol that is an important raw material for plastics. With the help of process simulations and machine learning methods, they are investigating how the material and energy balances can be improved.

A special chemical is also needed to remove interfering substances and thus obtain completely organically degradable BPS for the first time. The researchers have already developed the main features of this and applied for a patent for it. They want to further refine this technology as part of the third sub-project. Another aim is to utilise the residues generated during the production of bio-PBS to produce renewable electricity and heat, which can be used to operate the laboratory facilities. With the help of digital 3D models and the fully bio-based PBS, the researchers ultimately want to produce the first applicable products - for example packaging and medical materials.

There are currently a total of nine such third-party funded groups at the University of Oldenburg. They are intended to support outstanding and highly qualified young researchers like Walther on their way to professorships or other scientific leadership positions. Associated university partners involved in the "EcoPBS" project are the Hanze University of Applied Sciences (Groningen, Netherlands), the University of Twente (Enschede, Netherlands) and the Christian-Albrechts-Universität zu Kiel. Other co-operation partners are the gardening and landscaping company Oeltjen (Westerstede), the research institute Fair-Fusion (Emmen, Netherlands) and the plastics supplier Biovox (Darmstadt).