The latest episode in the American Chemical Society's (ACS') award-winning Global Challenges/Chemistry Solutions podcast series describes how the search for a less-expensive, sustainable source of biomass, or plant material, for producing gasoline, diesel and jet fuel has led scientists to duckweed, that fast-growing floating plant that turns ponds and lakes green.

Based on a report by Christodoulos A. Floudas, Ph.D., in the ACS journal Industrial and Engineering Chemistry Research, the new podcast is available without charge at iTunes and from www.acs.org/globalchallenges.

Floudas explains that duckweed, that green plant that floats on or near the surface of still or slow-moving freshwater, is ideal as a raw material for biofuel production.

It grows fast, thrives in wastewater that has no other use, does not impact the food supply and can be harvested more easily than algae and other aquatic plants. However, few studies have been done on the use of duckweed as a raw material for biofuel production.

In the podcast, he describes various scenarios for duckweed refineries. They would use proven existing technology to produce gasoline, diesel and kerosene. Those technologies include conversion of biomass to a gas; conversion of the gas to methanol, or wood alcohol; and conversion of methanol to gasoline and other fuels.

The results show that small-scale duckweed refineries could produce cost-competitive fuel when the price of oil reaches $100 per barrel. Oil would have to cost only about $72 per barrel for larger duckweed refiners to be cost-competitive.

Global Challenges/Chemistry Solutions is a series of podcasts describing some of the 21st century's most daunting problems, and how cutting-edge research in chemistry matters in the quest for solutions. Global Challenges is the centerpiece in an alliance on sustainability between ACS and the Royal Society of Chemistry.

Global Challenges is a sweeping panorama of global challenges that includes dilemmas such as providing a hungry and thirsty world with ample supplies of safe food and clean water, developing alternatives to petroleum to fuel society, preserving the environment and ensuring a sustainable future for our children and improving human health.