Yeast gets the boot at new UK biofuel centre
Scientists behind a pilot plant capable of turning straw into ethanol say the process could one day provide the UK with 10 per cent of its transport fuel.
The demonstration facility in Guildford is one of only a handful worldwide. It exploits a new strain of bacteria capable of breaking down anything from straw and other agricultural plant waste to domestic hedge clippings, garden trimmings and cardboard.
This means ethanol for blending with petrol can be produced more efficiently and cheaply than in the traditional yeast-based fermentation processes used in most commercial operations, says Paul Milner, fermentation development manager with TMO Renewables, the company behind the.
“Conventional ethanol production is energy-intensive, expensive, and time-consuming as the barley malt or other material being brewed needs to be heated up as a mash in feedstock pre-treatment,” Milner explained. “Then it is significantly cooled from that high temperature to a lower temperature for yeast fermentation, only to be re-heated when it is later distilled into ethanol.”
TMO's search for suitable bacteria involved screening thousands of different types found in the wild to identify one that could survive high temperatures and that likes feeding off a wide variety of plant based materials. The winning candidate was a member of the Geobacillus family usually found in garden compost heaps.
The next step was to alter the microorganism’s metabolism so that instead of producing lactic acid when it breaks down plant waste, it produces ethanol. The new strain, known as TM242, operates at between 60 and 70 degrees C.
Describing their work at the Autumn meeting of the Society for General Microbiology in Dublin, TMO scientists estimated that turning the 7 million tons of surplus straw available in the UK every year into ethanol could replace 10 per cent of the gasoline fuel used in the country.
"We have recently completed commissioning the UK's first cellulosic ethanol demonstration facility - one of just a handful worldwide," said Paul Milner. "We are constantly researching new, better ways to produce biofuels. We also believe that our process can be used successfully beyond biofuels to produce other high-value chemicals and drug ingredients that are currently derived from oil."