Yeast strain could lead to more efficient biofuel production

Biofuels are produced through the microbial fermentation of biomass crops, which yield alcohol-based fuels ethanol and iso-butanol if yeast is used as the microbe to convert sugars from biomass into biofuels.

‘At a certain concentration, the biofuels that are being created become toxic to the yeast used in making them,’ said Yong-Su Jin, an assistant professor of microbial genomics in the U of I Department of Food Science and Human Nutrition. ‘Our goal was to find a gene or genes that reduce this toxic effect.’

Jin worked with Saccharomyces cerevisiae, the microbe most often used in making ethanol, to identify four genes – namely MSN2, DOG1, HAL1 and INO1 – that improve tolerance to ethanol and iso-butanol when they are over-expressed.

’We expect these genes will serve as key components of a genetic toolbox for breeding yeast with high ethanol tolerance for efficient ethanol fermentation,’ he said.

To assess the over-expressed genes’ contribution to the components that have limited biofuel production, the scientists tested them in the presence of high concentrations of glucose (10 per cent), ethanol (five per cent) and iso-butanol (one per cent) and compared their performance with a control strain of Saccharomyces cerevisiae.