GM grass cuts biofuel costs by twenty per cent shows research
Research shows that reducing the natural defences of switchgrass – a significant US biofuel source – increases the yield of ethanol by more than a third.
Research shows that reducing the natural defences of switchgrass – a significant US biofuel source – increases the yield of ethanol by more than a third.
Scientists at the US Department of Energy’s Oak Ridge National Laboratory and The Samuel Roberts Noble Foundation - a non-profit research institute focused on agriculture - demonstrated that a slight alteration of the plant’s genetics made it easier to break down, potentially reducing the cost of converting it to biofuel by 20 per cent.
By using a plant that was genetically modified to contain less lignin – a structural molecule which strengthens the plant like a glue but also provides a defence against disease and pathogens - the scientists found that more alcohol was produced in fermentation.
In the modified plant, enzymes more easily broke down sugars for fermentation into alcohol, meaning fewer enzymes were required, according to Dr. Jonathan Mielenz – co-author of the research paper published in PNAS this week.
“You could decrease the amount of enzyme by up to four fold to get the same amount of ethanol in the modified compared to the unmodified plant and this turned out to be an astounding decrease in the cost because enzymes are very expensive,” said Mielenz.
“That’s certainly going to be helpful for commercialisation,” he added.
Switchgrass was chosen for the study because it is a non-food crop that grows well without needing high rainfall and it is perennial - once planted the grass can be harvested for at least 10 years without reseeding.
It also grows without needing high levels of fertiliser and herbicide which can be harmful to the environment.
Mielenz believes these characteristics mean it could have positive impacts for sustainable biofuel production.
Biofuels are a lucrative industry – oil giant Shell and sugar producer Cosan announced further details of their $12 billion joint venture this week.
But neither the Noble Foundation nor Oak Ridge intend to commercialise the results of their work.
“The results, as far as plant material, will be made available to others so the goal of the Center is not to keep it to ourselves but to get it out to be commercialised by others,” said Mielenz.
Matthew Nelson, a plant scientist at the University of Southampton focusing on biofuels, said he feels the research is sound and highlighted the methodology which he felt was close to how the research would be done if scaled up to industrial level.
But Nelson noted: “the major worry is obviously if this genetic manipulation were to have adverse side effects on plant growth but in this glasshouse experiment, this wasn't the case."
He is keen to see field trials that show how the plants would do in a natural environment.
According to Mielenz, the modified plants look normal in laboratory conditions but further tests will be required and he recognises it is currently small scale.
“But the plant should respond in a proportional manner to what we saw on a small scale at larger scale.
“So you should be able to get more ethanol [from the modified switchgrass] under the same industrial conditions and I would expect at least 25 per cent more,” said Mielenz.
For further information:
Original research paper - PNAS
The Samuel Roberts Noble Foundation
Cosan and Shell Announce Raizen
Image: Doctor Swan | Flickr