Scientists from the Norwich Research Park have found strains of yeast that look particularly useful for turning agricultural by-products, such as straw, sawdust and corncobs, into bioethanol.

S. cerevisiae yeast Image by Kathryn Cross and Carmen Nueno Palop

It is estimated that more than 400 billion litres of bioethanol could be produced each year from crop wastage.

The research team say that their findings could help to create biofuel which is more environmentally friendly and ethically sound than other sources because it would make use of waste products.

Processes to generate bioethanol from straw and other by-products are currently complex and inefficient.

This is because high temperatures and acid conditions are necessary in the glucose-release process. But this treatment process causes the waste to breakdown into compounds which are toxic to yeast (furfural and hydroxymethylfurfural) – making fermentation difficult.

One way to avoid these problems is to use genetically modified yeasts, but this new research has found five strains of naturally occurring yeasts which could be used successfully in the fermentation process.

Dr Tom Clarke, from UEA’s School of Biological Sciences, said: “Dwindling oil reserves and the need to develop motor fuels with a smaller carbon footprint has led to the explosion of research into sustainable fuels.

“Breaking down agricultural waste has previously been difficult because many strains of yeast necessary for fermentation are inhibited by compounds in the straw. Their toxic effects lead to reduced ethanol production.”

The UEA researchers worked with the National Collection of Yeast Cultures, a BBSRC-supported National Capability at the Institute of Food Research, as well as the Biorefinery Centre, also based at IFR.