Using a parasite pest to create bioluminescent wood

In order to defy climate change and the bark beetle, more deciduous trees are being planted in Swiss forests. If possible, their wood should be used several times before it ends up as firewood, thus releasing the previously bound CO? back into the atmosphere. At present, however, hardwood is still too often used directly for heating.

One possibility is to equip the natural material with new properties – in technical terms: functionalities – and transform it into magnetic, waterproof or electricity-generating wood, for instance.

A team led by fungal researcher Francis Schwarze from Empa's Cellulose & Wood Materials lab in St. Gallen is currently pursuing another idea for a new type of composite material based on hardwood: luminous wood. In addition to applications in technical fields, the luminous wood could be processed into designer furniture or jewelry.

This has been achieved thanks to a parasite: The honey fungus is a pathogen that causes white rot in trees and is therefore actually a wood pest. Some species produce the natural substance luciferin, which is stimulated to glow in a two-stage enzymatic process. Wood permeated by fungal threads therefore emits a green light.

The ringless honey fungus (Desarmillaria tabescens) turned out to be particularly powerful. After preliminary tests with different types of wood, Schwarze started with balsa wood (Ochroma pyramidale), a wood with a particularly low density. X-ray diffraction analyses showed that the stability of the wood does not diminish as a result: The cellulose, which provides tensile strength in the wood, remained intact.

Image source: Swiss Federal Laboratories for Materials Science and Technology.