Video transcript: Bugs to biofuel: the gribbles
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Video shows the gribble
Professor Simon McQueen-Mason, Department of Biology, The University of York
What we can see on the screen here is a four-spot gribble. And this animal is about 2mm long. So these animals have specialised on living on a diet of wood, they're marine wood borers. We're interested in them because they have an unusual mechanism for digesting wood.
Video shows Professor McQueen-Mason in the laboratory
The gribble is really interesting in terms of industrial biotechnology. One of the aims that we have in the near future is to be able to make fuels, biofuels out of materials which don't normally go into the food chain, like wood, things that normally end up on the rubbish dump for example. And what we're after is means of converting those materials that we know are potentially rich in sugars into sugars that you can ferment and to do that we've got to digest them.
Video show the gribble under a microscope
We're interested in this animal because of the fact that it's got a sterile gut. We know that it has to digest the wood just using enzymes that it produces itself. And what we see in there is that there are a lot of enzymes that are associated with converting complex polysaccharides into sugars. Digesting wood just with enzymes is really hard. There are a lot of people in industry and in science that are still trying to do just that at the moment.
Will Eborall, PhD student, Department of Biology, The University of York
We think that the enzymes that I'm working on pre-treat the wood to allow the other enzymes, the glycosyl hydrolases, to break down those complex polysaccharide sugars into simple sugars that the gribble can use for food. Yea, it is very special it's the only animal that we know of that can digest wood by itself in this way. It's important to research these enzymes because so far in industry no one has come up with a viable simple way of doing this, and people who study other animals, like termites or cows even, they haven't found a way to do it either because they rely on thousands of different species of bacteria and fungi, whilst the gribble does it itself.
Professor Simon McQueen-Mason
So the apparatus behind me here, this is almost, think of this as the industrial equivalent of the gribble gut. This is just a demonstration scale of course, this is nowhere near the industrial scale. But this machine here is the place where we would digest the wood into the sugars that we can ferment. And to do that we need to use extremely high temperatures and high pressures in order to blow the structure of the wood open so that enzymes can work on it. And that's analogous in some ways to what we think the gribble is doing.
Video shows an illustration of the gribble GH7 cellobiohydrolase enzyme structure
The gribble, hopefully, will show us how we can do this within a simple, one or two enzyme step perhaps that would allow access to these complex polysaccharides. We know that it must be able to do it because all it eats is wood so if it can do it, we should be able to transplant this into an industrial setting where we can use it to our benefit.
Professor Simon McQueen-Mason
So we can't make more fuel out of food, we know that, so we need to go to the materials that we produce in agriculture which are not food materials. And that is the woody bits of crops, like straw, it's wood waste and it's also the woody biomass from dedicated biomass crops that we can grow on marginal lands where we have little impact on food production or on biodiversity.
So the end point of all of this research is that using what we learn from the gribble, we can lower the costs of the pre-treatment of the production of the sugars from the woody biomass so we can then have cheaper sugars that we can ferment to produce cheaper and better biofuels for our transportation systems.
This is a really good example of where BBSRC investment in fundamental science is underpinning our move towards sustainable industrial biotechnology. We're understanding the mechanisms of digestion in the gribble. We're starting to understand the structure of some of the enzymes that are involved in all of that process. And now we can see how we can take some of that knowledge and move it into this whole context of producing more sustainable biofuels.
This video may be reproduced in its entirety with due credit to BBSRC.
All media copyright BBSRC unless otherwise stated.
Image, music and video credits:
- Biofuels video copyright Rothamsted Research
- MicroCT anim by Graham Malyon, Uni Portsmouth and Jan van den Bulcke, Uni of Gent
- Enzyme anim by John McGeehan and Richard Martin
- BBSRC ident by biganimal.co.uk
- Sound from cinephonix.com