Genetically modified micro-organisms for biobutanol production

Genetically modified micro-organisms could one day make it easier and cheaper to produce biobutanol, experts say. The symposium "Biofuels, from Paddock to the Pump" [*.pdf] convened by the Australian Institute of Agricultural Science and Technology in Canberra this week will hear about future directions in biofuel technology and ways of meeting national biofuel targets.

Speaker Leo Hyde, research and development manager at DuPont Australia, says improving the yeasts and bacteria that turn raw biomass into fuel is a major step in reducing the use of fossil fuels. Hyde says the company is developing bacteria specifically tailored to the production of butanol (see earlier post).

Like ethanol, biobutanol can be produced from the sugars contained in crops such as maize, sorghum, cassava or sugarcane and from cellulosic waste.

"We have bugs now but they're not efficient enough," Hyde says. "What we're working on is another bug that we believe will be far more efficient than the current process [of producing butanol]. "You'd re-engineer it to make the butanol pathway more efficient. We'll modify pathways, how it uses energy, to improve the yield of the product you want."

What are the benefits? Phillip Calais is a renewable energy consultant and former lecturer in environmental science at Murdoch University, where he's involved in a biofuels project. He says there are benefits in using genetically modified or GM bugs in the fermentation of fuels like butanol, which he says is more "oil-like" than ethanol and mixes better with petrol, but is more difficult to produce:

Butane is made from a raw product that is then broken down to starch or sugars, fermented and purified. "With butanol, fermentation has to be very pure. If there are any weird strains of bacteria it really upsets the fermentation process," he says:
ethanol :: biomass :: bioenergy :: biofuels :: energy :: sustainability :: bacteria :: biotechnology :: biobutanol


The micro-organisms that are currently used are also destroyed once butanol reaches a certain concentration, which means more costly and time consuming processing is needed to purify it after fermentation. "By using GM you can actually breed up different bugs that can survive a higher concentration of purity in the butanol," Calais says. "If you can make it more concentrated in the first place by using better bugs you can do less processing later."

What about the risks?

The use of GM organisms holds promise for "certain niches", says Adrian Lake founder and president of the Biodiesel Association of Australia. But he says the technology is still being developed and has potential risks.

"There's potential danger in changing any bugs," he says. "If it's an organism that's extremely aggressive and has to be highly controlled because it will replicate and damage other organisms, that's a concern."

More information:

BP: Biobutanol fact sheet [*.pdf].