Scientific American: “Visualize three tons of moldy bread.” It’s not the most appealing image, perhaps, but it’s a description of the moist mound of growth media tended by bioscientist Cliff Bradley and his partner, chemical engineer Bob Kearns at their biofuel facility in Butte, Mont., that could help cut ethanol costs at the fuel pump. Selected soil fungi that eat cellulose–the hard-to-digest, structural component of woody plants–thrive on the big pile of putrefaction from which Bradley and Kearns …