Researchers Develop Cellulose-Ethanol-Production Yeast Strain Which Tolerates Furan-Inhibitors from Preteated Biomass

One of the effectsof lignocellulosic biomass pretreatment in cellulose-ethanol production is the generation of "furan-inhibitors", which can inhibit the ethanol-fermenting yeasts. Furan-inhibitors furfural (2-furaldehyde) and HMF (5-hydroxymethyl-2-furaldehyde) are by-products from the degradation of sugars during biomass pretreatment. These inhibitors are reported to damage yeast cell walls and membranes, disrupt yeast genetic material, and interfere with yeast enzymes' fermentation abilities.

Recently, researchers from the National US Department of Agriculture, USA developed a yeast strain that is more tolerant to inhibiting compounds present in bioethanol production. From their study, the researchers found out that the NRRL Y-50049 strain of Saccharomyces cerevisiae was capable of fermenting plant sugars into cellulosic ethanol in the presence/interference of inhibitory compounds. The researchers attributed the tolerance of the yeast strain  to a specific gene in the yeast cell. The tolerance to furfural and HMF was attributed to YAP₁ gene which provided the yeast's resistance to these compounds. More information can be obtained at the USDA website (URL above).