Plugging in to plant roots

Cast-off electrons in a plant's roots can provide electricity, a Dutch team reports. Now, through a spin-off company, it hopes to grow grassy generators on rooftops and promote decentralized electrical production in wetlands in developing countries. Plants exude a variety of waste products that microbes consume, such as glucose, acetate, butyrate, and propionate. The underground interaction leaves spare electrons in the surrounding soil and water, which researchers-led by Bert Hamelers at Wageningen University, in the Netherlands- began tapping in experiments in 2007. They were already working on using so-called microbial fuel cells (MFCs) to treat wastewater when they realized that plant roots improved the performance of the fuel cells.