Scientists from the Delft University of Technology (TU Delft, the Netherlands) report the introduction of a single bacterial gene into yeast which can achieve three improvements in bioethanol production from agricultural wastes. These three improvements can be described in the following keywords: (1) less acetate, (2) elimination of glycerol by-product, and (3) more ethanol. Pretreated lignocellulosic biomass, prior to ethanol fermentation, is said to contain high amounts of acetate which may adversely affect ethanol production performance in yeast. Glycerol is also one inevitable by-product which can be produced by yeast during ethanol fermentation (about 4% of the sugar is reportedly "lost to formation of the byproduct glycerol"). Both conditions can decrease ethanol yields. According to TU Delft researchers, "yeasts (at least in theory) can convert the harmful acetate to ethanol. However, just one single gene is missing in the yeast. "By introducing a single gene from the bacterium Escherichia coli, researchers of the Netherlands-based Delft University of Technology and the Kluyver Centre for Genomics of Industrial Fermentation enabled this conversion of acetate to ethanol by yeast. This replaced the normal role of glycerol so efficiently that key genes in glycerol production could be removed, thus completely abolishing glycerol production." The researchers hope to collaborate with industrial partners to accelerate industrial application and implementation. Details of their metabolic engineering strategy for ethanol fermentation improvement can be accessed in the journal, Applied and Environmental Microbiology (URL above).