Both Corn and Corn Stalks Consist of Polymers of Glucose

Both corn and corn stalks consist of polymers of glucose. The polymer in corn is amylose (starch), and the polymer in corn stalks is cellulose. We eat the corn and convert the amylose to ethanol for use as a fuel, and throw the corn stalks away or feed them to cattle. Why can't we obtain a larger economic benefit from the corn stalks? Mention the difference between amylose and cellulose in your response.