Biodiesel from plant oils could be the fuel of the future, but the low quality of certain plant oils means that getting there will take some engineering. So, researchers are turning to genetics for a solution. They’ve developed a transgenic soybean line that could dramatically increase biodiesel performance. Biodiesel performance relies on the fatty acid composition of the source oil. On average, soybean oil is only 25% oleic acid, which is a desirable monounsaturated fatty acid, and 13% palmitic acid, an undesirable saturated fatty acid. This fatty acid profile negatively affects biodiesel’s rate of nitrogen oxide emission and freezing point. Through metabolic engineering, the soybean genes FAD2-1 and FatB were down-regulated using RNA interference technology to increase the production of oleic acid to nearly 95% and decrease the production of palmitic acid to less than 3%, with no detectable differences in the fatty acid chemical structure between modified and standard soybean lines. This high-oleic-acid soybean line also has consumer health benefits and food manufacturing applications. Metabolically engineered plants like this can open the door to large-scale production of high-quality oil for a variety of human uses, especially in the bioenergy sector.