The “now hiring” sign is up online for Emmetsburg, Iowa, where the nation’s largest maker of ethanol used for motor fuel is putting the final touches on a manufacturing plant that will rely not on corn, but on the stalks and cobs left behind. The company, Poet, is looking for an accountant, electricians, lab technicians, a supervisor for starch and cellulose operations, and more. Large flatbed trucks have already dropped off2,600 tons of big bales at the distillery’s 22-acre stack yard. Equipment is visible from miles away across the flat, open prairie. The process is a bit like making moonshine on an industrial scale, helped along by some high-tech, bioengineered enzymes.