SynGest says it will build the plant near Menlo, Iowa, about 40 miles west of Des Moines.
The company says it has signed an agreement to buy 75 acres, where it will build a plant that uses 150,000 tons of corncobs annually to manufacture 50,000 tons of bio-ammonia. SynGest says it's the first plant of its kind in the nation.
On Monday, company CEO Jack Oswald estimated the plant will employ about 40 people full-time, and 500 people will work on construction. Startup is planned for fall 2009 or spring 2010.