Forests cover about a third of the planet and play a fundamental role for life on Earth. According to Peter Wohlleben, author of the book “The Secret Life of Trees”, through fungal weaves, specimens of a forest can communicate with each other, exchange nutrients, help out the weakest plants, and organize survival strategies, which is essential for the healthy growth of individuals. The preservation of existing forests and the creation of new ones are essential for biodiversity and natural recovery, but also to meet the demand for wood. According to a report by the WWF (World Wide Fund for Nature), it is estimated that the amount of wood harvested in the world will triple by the year 2050, with the increase in population and income in developing countries. In addition, it is estimated that there will be an increased use of wood to manufacture biofuels, pharmaceuticals, plastics, cosmetics, consumer electronics and textiles. Searching for wood substitutes can be a smart path towards a sustainable future, especially if the alternatives are made using waste generated by other industries. Pyrus, for example, is an oil-free wood material produced sustainably with bacterial cellulose waste repurposed from the kombucha industry.
Wood basically consists of cellulose and lignin. Cellulose is the most abundant organic molecule on the planet and gives plants rigidity and firmness. Lignin acts as a glue and fulfills the functions of impermeability and resistance against biological attacks on plant tissues. The good news is that cellulose can be found in abundance in the production of kombucha (a fermented drink made from the symbiosis of bacteria and yeast).
We spoke with Gabe Tavas, creator of Pyrus, who also founded the company Symmetry Wood. “Through independent research, I realized that bacterial cellulose is highly similar to the cellulose that comprises about 50% of tree-based wood.” To develop the product, this cellulose is poured into a mold together with agar, an algae-based gel that acts as a binder. They dehydrate the material and then place the hardened pulp sheet under a mechanical press to flatten it. What remains is a sheet that can be sanded and cut like wood from a tree, and which is also biodegradable. “The result is a dense, dark-colored material that resembles many high-value woods driving deforestation in tropical areas like the Amazon Rainforest.“
The design won the 2021 USA James Dyson Award, an international student design award. With the cash proceeds received, the plan is to expand its production facilities and develop 3D printing processes. Tavas adds that “3D printing is another area of active research for Symmetry Wood and will require a new version of Pyrus. Bacterial cellulose likely cannot be printed with conventional fused deposition modeling (FDM), as a heat-based process will deform and weaken most forms of cellulose. Symmetry is therefore exploring alternative approaches. If successful, 3D printing Pyrus would allow people to create complex wood geometries without cutting down trees and eliminate the hazardous sawdust generated during woodworking. It would be a sustainability and health win!”
Currently, the material has been used in smaller scale projects, such as in decorative or jewelry applications and guitar picks. “Getting it to the building scale will require additional research and development, and we would probably start with veneers and non-load-bearing structures. Our team is beginning to conduct material tests that will allow us to better gauge its full potential for architecture.”
Evidently, several tests and trials are still needed for the product to have commercial viability. But using waste from another industry to obtain a material with a similar performance to wood opens our eyes to the possibilities of materials that may otherwise pass unnoticed. Gabe mentions that “Designers should also keep in mind that the industrial status quo is illogical even without climate change as a consideration. The world economy's annual consumption of resources is so large that it could only be replenished by at least 1.6 Earths, as if that were even a long-term option.”
