The Little Green Plant That Could: Duckweed as a Renewable and Sustainable Biofuel Feedstock

To meet the energy demands of a booming global population and preserve biosphere integrity, we must reduce our dependency on fossil fuels and find a more cost-effective and sustainable energy source. The development of renewable biofuels will aid in overcoming these daunting economic and environmental challenges. Corn, the main biofuel feedstock in the United States today, has serious drawbacks as an energy source; its high-maintenance cultivation requires significant amounts of fertilizer and freshwater while competing with food crops for arable land. In contrast, the small aquatic plant duckweed has emerged as a highly promising biofuel feedstock. Its composition—high starch and low lignin—is ideal for ethanol production. Furthermore, duckweed does not compete with land crops, grows rapidly, and is easily harvestable. We are actively constructing a demonstration pipeline to assess the potential of duckweed as a renewable and sustainable crop for ethanol production. Liquid sewage is used as an inexpensive fertilizer source to support duckweed growth, and post-harvest, the cleaned wastewater can be recycled. Optimization of this new approach involves screening duckweed plants collected from around the world to find a strain that is best suited for ethanol production. However, morphological identification of duckweed species and ecotypes can be difficult, as many appear similar or identical. Thus, we are employing DNA-based methods in the laboratory to develop reliable methods of distinguishing duckweed strains. These efforts will lay the groundwork for future experiments, allowing us to gain much needed insight into basic duckweed biology.