GM yeast could fix food vs. fuel debate around bioethanol

Scientists have created a genetically modified yeast that could quicken the path towards synthetic yeasts for a number of industrial applications, including the creation of bioethanol.

The Tufts University researchers have created a yeast that can more efficiently consume xylose, in turn enabling the yeast to grow faster and to higher cell densities, according to their study, published in the journal Nature Communications.

When fed nutrients, organisms such as bacteria or yeast can turn into “little factories” to produce products ranging from biofuels to pharmaceuticals and industrial chemicals. The problem, however, is the efficiency with which feedstocks are turned into the final product, “particularly when the feedstock is not something the bacteria or yeast normally “eat”,’ according to a Tufts University press release.

The Tufts University researchers took a different approach, genetically modifying the yeast to increase the number of genes that are activated by, and direct the breakdown of xylose. This allowed them to preserve a more natural interaction between the genes that control feeding, and those that govern survival. Labelled XYL, the yeast cells grow more rapidly and to higher cell densities.

“Instead of building a metabolic framework from the ground up, we can reverse engineer existing regulons to enable an organism to thrive on a novel nutrient,” said Nikhil U. Nair, Ph.D., assistant professor of chemical and biological engineering at Tufts and corresponding author of the study.

“Adapting native regulons can be a significantly faster path toward the design of new synthetic organisms for industrial applications.”


Food vs fuel

According to the researchers, one application of their research could be bioethanol production from crops.

Controversy surrounds crop based biofuels produced from plants such as corn, with critics suggesting they threaten food supplies.

Xylose is derived from the otherwise indigestible parts of plant material. The new GM yeast provides a means to ferment this xylose, producing biofuels that don’t affect food supply.

“Nature has already done the work of turning genes and metabolic pathways to the environment of the organism. Let’s make use of that when introducing something new on the menu,” Nair said.