Material Luminous wood thanks to a mushroom

Empa researchers have discovered how wood can be enhanced by the bioluminescence of a fungus. In addition to applications in the technical field, the glowing wood could also be processed into designer furniture or jewelry.

The team led by mycologist Francis Schwarze has been studying the fungus Desarmillaria tabescens, a wood parasite. It produces the natural substance luciferin, whose luminescence is stimulated by an enzymatic process. Wood that is permeated by fungal threads emits a green light.

"Naturally luminescent wood was first described around 2,400 years ago by the Greek philosopher Aristotle," explains Francis Schwarze, who was quoted in a press release issued by the Swiss Federal Laboratories for Materials Science and Technology (Empa) on Thursday. The interwoven structure of fungus and wood can be described as a natural biohybrid, a combination of living materials.

However, what nature seems to achieve effortlessly has so far remained a challenge for biotechnology. The Empa team has now succeeded for the first time in inducing and controlling the process in the laboratory, as the work published in the journal "Advanced Materials" shows.

Maintaining stability

Schwarze tracked down the luminescent fungi in nature, analyzed them in the laboratory and deciphered their genetic code. The fungus Desarmillaria tabescens proved to be particularly efficient.

After initial experiments with different types of wood, Schwarze decided on balsa wood, which has a particularly low density. Using spectroscopy, the scientists observed how the fungus breaks down the lignin, which is responsible for stiffness and compressive strength.

X-ray diffraction analyses showed that the stability of the wood was not lost: The cellulose, which is responsible for tensile strength, remained intact.

The biohybrid of fungus and wood develops its maximum luminosity after three months in an incubator. Desarmillaria tabescens likes it particularly moist: The balsa wood samples absorbed eight times their weight in moisture during this time.

As soon as it comes into contact with the air, the enzymatic reaction in the wood begins. The green glow unfolds its full splendor after ten hours. This process currently takes around ten days. "We are now optimizing the laboratory parameters in order to increase the luminosity even further in the future," the scientist concluded.

SDA