Scientists dramatically improve poplar's capacity to clean up polluted sites - potential to couple phytoremediation to bioenergy

Scientists led by the University of Washington's Sharon Doty report that they have succeeded in genetically engineering poplar plants with a dramatically improved capacity to clean up contaminated sites. Doty, an assistant professor of forest resources, told Biopact that the ideal end of phytoremediation projects based on the trees would be to use the plants as a bioenergy feedstock. After all, poplar has been identified as a promising, fast-growing energy crop (previous post). Researchers since the early '90s have seen the potential for cleaning up contaminated sites by growing plants able to take up nasty groundwater pollutants through their roots. Plants break certain kinds of pollutants into harmless byproducts that the plants either incorporate into their roots, stems and leaves or release into the air. The problem with plants that are capable of doing this is that the process is slow and halts completely when growth stops in winter. Using plants in this way - the process known as phytoremediation (schematic, click to enlarge) - often hasn't made sense given the timetables required by regulatory agencies at remediation sites. Together with scientists from Oregon State University and Purdue University, Doty engineered trees that were able to do the cleaning much faster. The transgenic poplars take as much as 91 percent of trichloroethylene, the most common groundwater contaminant at U.S. Superfund sites, out of a liquid solution. Unaltered plants in the same laboratory setting removed only 3 percent. The poplar plants - all cuttings just several inches tall growing in vials - also were able to break down, or metabolize, the pollutant into harmless byproducts at rates 100 times that of the control plants. The scientists publish their findings in this week's Proceedings of the National Academy of Sciences.  Read more By Biopact team