Wisconsin Alumni Research Foundation

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Sugar Transport Genes from Yeast to Enhance Ethanol Production
WARF: P08060US

Inventors: Thomas Jeffries, Ju Yun Bae, Bernice Chin-yun Lin, Jennifer Headman

The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in xylose transporter genes that can be used to enhance ethanol production.
Overview
Because ethanol can be produced from sugars derived from renewable plant biomass, it offers a promising alternative to non-renewable fossil fuels. Corn is currently the main source of carbon used in ethanol production, but this use of corn is not economically sustainable. To meet the increased demand for ethanol, other biomass must be used. However, biomass from sources like agricultural waste and cellulosic materials contains large amounts of xylose and other sugars, which are difficult to ferment.

Microorganisms, such as yeast, are used to convert sugars like glucose and xylose into ethanol. Saccharomyces cerevisiae is the yeast most commonly used for industrial applications, but wild type S. cerevisiae cannot grow on or ferment xylose. Native strains of xylose-fermenting yeasts, such as Pichia stipitis, convert xylose to ethanol slowly and with low yields.

One approach to increasing the efficiency of ethanol production from biomass is to increase the uptake of sugars by yeast. S. cerevisiae and other glucose-fermenting yeasts have sugar transporters that facilitate the uptake of glucose. Some of these transporters also promote the uptake of xylose, but at a lower rate and with lower affinity. As a result, xylose uptake and utilization is impaired until the glucose is consumed. To promote xylose utilization, sugar transport proteins with high affinity for xylose are needed.
The Invention
UW-Madison researchers have identified xylose transporter genes from the xylose-fermenting yeast P. stipitis. One of the genes encodes the first known sugar transport protein with greater affinity for xylose than glucose. Over expression of these genes enhances the uptake of xylose and/or glucose, leading to increased ethanol production. The genes can be incorporated into recombinant strains of S. cerevisiae to allow the yeast to grow on and efficiently ferment xylose.
Applications
  • Ethanol production
Key Benefits
  • Increases the rate of ethanol production
  • Provides enhanced uptake and fermentation of xylose and/or glucose
  • May make the conversion of xylose-containing biomass into ethanol more cost effective
For current licensing status, please contact Jennifer Gottwald at [javascript protected email address] or 608-960-9854

WARF