Tiny gribble creature could hold secret to turning wood into biofuels

3 Dec 2018

Image: © Thanakon/Stock.adobe.com

In our efforts to produce new, sustainable biofuels, a tiny creature called the gribble could help us achieve a major breakthrough using wood.

The world’s attention and focus might be trained on Poland as COP24 gets underway, but efforts to limit the damage of carbon emissions on our planet continue to develop in the meantime.

One such effort is the development of renewable and sustainable liquid biofuels as a better alternative to fossil fuels such as oil, and now an international team from the UK and Brazil has found an answer in the unlikeliest of places.

Publishing its findings in Nature Communications, the research team revealed that analysis of the digestive system of a curious wood-eating crustacean might hold the key to producing biofuel.

These small marine invertebrates, going under the peculiar name of gribble, have evolved to perform an important ecological role by eating huge quantities of driftwood washed into the sea from rivers. What has puzzled scientists for years, however, is how the gribble is able to break through lignin, the highly resistant coating that wraps around the sugar polymers that compose wood.

Two gribble on either side of a piece of wood.

Gribble on a piece of wood. Image: Claire Steele-King and Katrin Besser/University of York

Blue blood

By studying the gribble’s gut, the team found that proteins called haemocyanins play a key role in extracting sugars from wood. They are perhaps best known for their role in transporting oxygen in invertebrates, similar to how haemoglobin does in us. However, it differs in that haemoglobin binds oxygen through its association with iron, resulting in blood’s red colour, whereas haemocyanins bond with copper, resulting in the blue colour.

Using the highly reactive chemical, gribble have harnessed oxygen’s power to attack the lignin bonds that hold wood together. By understanding this, the researchers are closer to finding a way to convert wood into low-carbon biofuel.

“Gribble are the only animal known to have a sterile digestive system. This makes their method for wood digestion easier to study than that of other wood-consuming creatures such as termites, which rely on thousands of gut microbes to do the digestion for them,” said Prof Simon McQueen-Mason, who led the research team.

“We have found that gribble chew wood into very small pieces before using haemocyanins to disrupt the structure of lignin. GH7 enzymes, the same group of enzymes used by fungi to decompose wood, are then able to break through and release sugars.”

Unlike other biofuels based on food crops, woody plant biomass is the most abundant renewable carbon resource on the planet.

Colm Gorey was a senior journalist with Silicon Republic