Why use living cells? Researchers are making chemicals with enzymes alone

Today's nearly $70 billion U.S. biofuels economy is powered by two technology toolboxes. Biochemical technologies—used to produce around 17 billion gallons of ethanol annually—leverage microorganisms to convert plant biomass sugars into alcohols, other biofuels, or chemicals. Chemical technologies, the second toolbox, use catalysts to turn biomass and wastes into similar target products.