With the help of a fungus:

Swiss researchers make wood glow

Wood samples treated with the hallimash fungus Desarmillaria tabescens glow green in the dark. Picture: Empa(Bild: Empa)

Researchers at the Swiss Federal Laboratories for Materials Science and Technology (Empa) have found a way to enhance the value of wood using the bioluminescence of a fungus. In addition to applications in the technical field, the luminous wood (photo) could also be processed into designer furniture or jewelry.

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

Aristotle already described luminous wood
"Naturally luminous wood was first described around 2400 years ago by the Greek philosopher Aristotle," Francis Schwarze was quoted as saying in an Empa press release on Thursday. The interwoven structure of fungus and wood can be described as a natural biohybrid - a combination of living materials.

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.

Genetic code of the fungus deciphered
Schwarze tracked down glow-in-the-dark fungi in nature, analyzed them in the laboratory and deciphered their genetic code. The fungus Desarmillaria tabescens proved to be particularly efficient. In nature, bioluminescence occurs in a wide variety of organisms. The glow is caused by chemical processes that release energy as light and heat.

After initial experiments with different types of wood, Schwarze opted for 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.

Stability of the wood does not suffer
X-ray diffraction analyses show that the stability of the wood was not lost: The cellulose, which is responsible for the tensile strength, remained intact, the scientists report.

The biohybrid of fungus and wood develops its maximum luminosity after being placed in an incubator for three months. 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 to increase the luminosity even further in the future," says Schwarze.