Last year, for the first time ever, Japanese scientists were able to produce nanocellulose in space. In layman's terms, they managed to make wood without trees at the International Space Station, 400 km above earth. What made this possible is an enzyme originally found in the volcanic soil on the Izu Peninsula in Japan and later harnessed by synthetic biologists. One of them is Robert Pylkkänen, a doctoral student at Aalto University.
In public discussion about sustainability the need for sustainable resources is often overlooked or entirely forgotten. For example, there simply isn't enough waste or biomass on our planet to satisfy the world's need for fuels and materials. In order to reduce our dependence on oil we need synthetic biology, a technology that helps to convert cells into living factories.
Some of the most exciting research in this field happens in Finland and is very close to home for Finns, since it aims at "making wood without trees". Currently the Finns and the Japanese are collaborating on a project to build cellulose chains from individual sugar molecules. The project is led by Merja Penttilä, research professor at VTT in Finland, and Associate Professor Kiyo Igarashi from the University of Tokyo.
At Aalto University's Center for Young Synbio Scientists, led by Professor Penttilä, doctoral student Robert Pylkkänen researches how ordinary baker's yeast could be used to help produce cellulose without trees or other plant-based biomass. This would provide some new answers to producing materials in more sustainable ways. The focus of Pylkkänen's research is the enzyme. Usually we think of enzymes as proteins that biologically catalyze the breaking down, or degrading, of biomass. They are active in forests turning debris into soil and in our stomachs helping to digest food. In some cases this reaction can be reversed, and degrading enzymes can be used as synthesizing enzymes. They become builders. In the field Pylkkänen is pursuing they are employed to build cellulose.
The enzyme that is the focus of Pylkkänen's research was originally discovered in the volcanic soil in Japan and is produced by a bacteria. This enzyme naturally breaks cellulose to sugars. Pylkkänen has been able to modify traditional baker's yeast to produce the same enzyme as the Japanese bacteria. This allows the enzyme to be produced in higher quantities. The overall aim is also to modify the yeast so that it produces the enzyme outside of its cell. This enables the yeast to produce the enzymes continuously, while reproducing themselves at the same time. This makes continuous production possible without constantly adding new enzymes.
In nature, cellulose is produced everywhere by plants and trees through biosynthesis, a complex and fairly slow process. When humans want to use it for different applications, the wood material, composed of lignocellulose, is broken down in pulp mills using acid and high temperature to obtain cellulose and other chemical fractions. Only then can applications like construction materials, paper or tailored special components and hybrid materials be produced. The new technologies being developed mean we could replace some of the speciality materials currently made from traditional pulp.
In the Northern Hemisphere, it takes a spruce tree about 70 years to produce one cubic meter of wood. In a laboratory tank, we can make one cubic meter of nanocellulose, which is a much more refined form of cellulose, in two days. The sugars or other sustainable carbon sources needed in the process can come from organic waste streams, agricultural sidestreams or industrial CO2 emissions.Talk about turning a challenge into an opportunity!
The same enzymes Robert Pylkkänen has been researching and making in Espoo, Finland, were recently used in space at the International Space Station. The experiment was led by Associate Professor Kiyohiko Igarashi and his colleague Dr. Naoki Sunagawa from University of Tokyo, with whom the Finnish group collaborates. The ingredients were launched to the station by SpaceX, and homogeneous crystalline cellulose was made enzymatically at the station. The technology is suitable for use in space because it doesn’t require any extra heat, the process can fit in any shape, and requires no solvents or harmful chemicals before, during or after the production process.
While it is easy to think of making cellulose in space as a scientific gimmick, it is much more than that. Making material at a space station or a rocket may be one ingredient in revolutionizing space travel. But there's also a profound analogy between a space station and spaceship earth. "I believe that making cellulose in space in limited conditions leads us to think about our future of sustainable manufacturing," says Professor Igarashi.