(Deutsch) Das Projekt »Xylinum« beschäftigt sich vor dem Hintergrund der Ressourcenverknappung und Umweltbelastung durch erdölbasierte Kunststoffe, mit einer möglichen neuen Material- und Produktionskultur.
Xylinum is a research project that asks, ‘What could future materials and production processes look like?’ It has been known for a long time that micro-organisms can be used for industrial processes, such as yeast cultures for the production of bread, alcohol, or cheese. Since it is possible to decode the DNA of organisms, and even to alter it consciously, the so-called ‘white biotechnology’ has changed fundamentally. Now it has become possible to replace chemical with organic processes. This has already happened in the textile and detergent industry and shows a big potential in the production of energy or bio-plastics. Bacterial cellulose is such a material, which is produced by a bacterium called Acetobacter xylinum. In a liquid culture medium it transforms glucose into a cellulose fibre structure. The project has been realized in collaboration with the company Jenpolymers in Jena, Germany, which developed the technique that makes it possible to shape the material already during the production process in the culture medium.
The properties of the cellulose fleece have been adjusted for medical use. So far, the applications are hollow implants for bypass operations or as wound dressings. It is characterized by a three-dimensional nano-grid structure, which provides excellent mechanical properties. Its stability in a wet state is even comparable to that of steel or Kevlar®. Moreover, it is so pure that, if placed inside the human body, it is effectively colonized by the body’s own cells. It is therefore hypoallergenic and fully recyclable. Because the material is made for medical use inside the human body and on wounds, it binds a lot of water and needs to be dried afterwards, thereby losing volume.
A pivotal question of the project is how to process and use the material. To sum up the many different material samples that originated from the project and to make the material available to the public, a book has come out called Bakteriencellulose – Bebilderter Erfahrungsbericht einer Diplomarbeit [Bacterial Cellulose – An Illustrated Report of a Master’s Thesis].
The aim of the project was to create a blueprint for new materials and production processes. A stool was chosen as an object because it does justice to the properties of the material and has a clearly defined function, while providing a projection surface for the material: a stool is the most reduced piece of seating furniture, its function is clearly defined, and the material is thus the centre of focus. Due to its skin-like appearance, the cellulose material shows similarities to materials such as leather or parchment, which have a long tradition in furniture production. Thus covering furniture with parchment is one of the most sophisticated and expensive crafting techniques. The bacterial cellulose material fills the seating surface functionally, thus turning the object from a frame into a stool.
The design was based on experiences from various experimental material tests. Since neither the aesthetics nor the behaviour of the bacteria could be foreseen, the project produced many surprises. For example, the material with the best qualities for the bacterial coating happened to be wood. Being natural cellulose itself, it turned out to be an appropriate material for the frame construction. Alder wood was chosen because of its fine, regular structure and excellent drying properties. The connection between ring and legs was form-fit, and the edges were reinforced to prevent the material from being damaged. To make sure the connections remained stable after the construction was removed from the liquid, special glue that reacts well to the bacteria was used. For the final coating, the ring was filled with a mould that could be removed after the coating process.
The stool shows an attempt to integrate natural, unpredictable processes into a planned design process. It is possible to plan the construction and the material, but not to predict the shape after the drying process or the eventual appearance of the cellulose. This new way of production in a liquid growing medium which makes use of micro-organisms places consumer goods in a new context. In contrast to those manufactured in emission-producing factories, a new generation of products could be produced in a natural way, compared to a sprouting seed or a growing living being. The unique look of each stool supports this characteristic.
Bacterial cellulose is a material which is part of a new generation of materials that are highly specialized, sustainable to produce, and biodegradable. Since the measuring units that engineers and biochemist work with are coming closer and closer together, these two professions will increasingly overlap in the future. The biochemist will be the engineer of the future. Organisms found in nature will be copied and rebuilt for industrial use. The next step would be the entire new design of artificial systems that would fulfil the dream of not only imitating nature, but improving it. Regarding all of the promising prospects that this still-young discipline of science has to offer, they should nevertheless be critically examined with the danger of a possible genetic manipulation of living beings in mind.