DOVER, Del. (AP) -- The DuPont company has taken another step toward commercial production of biofuel using cellulosic ethanol.

The Wilmington-based company broke ground Friday on a cellulosic ethanol facility in central Iowa.

The $200 million facility in Nevada, Iowa is expected to be completed in mid-2014. It will be among largest commercial-scale cellulosic biorefineries in the world.

DuPont says the facility will be able to produce 30 million gallons of cellulosic ethanol annually using corn stalks and leaves. The company plans to contract with more than 500 local farmers to supply corn stalks and leaves to the Iowa facility.

DuPont also is working with other feedstocks for use in cellulosic ethanol, processing switchgrass in a testing facility near Knoxville, Tenn.

Copyright 2012 The AP.