SynGest Inc., a California-based company specializing in fuel and fertilizer production, has selected The Weitz Co. to construct a manufacturing plant in Guthrie County.

The Menlo plant will utilize existing technology to produce anhydrous ammonia from biomass, specifically from corncobs rather than a traditional fossil fuel or oil-based product, said Don Frazer, SynGest’s chief financial officer.

Chosen for its easy access to road and rail transportation, the plant will use 150,000 tons of locally supplied corncobs each year to manufacture 50,000 tons of bio-ammonia annually.

The company has an agreement to purchase a 75-acre parcel 45 miles west of Des Moines, Frazer said, and hopes to firm up financing and construction details within the next 60 days. Preparation work on the site is slated to begin this fall, and the 18- to 21-month build-out is expected to start in early 2010.

The plant will be situated on about five acres, which will allow for a degree of separation from its neighbors and leave room for possible future expansion, Frazer said.

The project has conditional agreements with several investors, and Frazer said SynGest is working closely with the Iowa Power Fund and Iowa Department of Economic Development to secure additional financing through loans and grants.

A SynGest subsidiary, SynGest Menlo LLC, will own and operate the facility, which will employ 40 people. The construction process may involve up to 500 workers, Frazer added.

“Timing is important,” he said. “We don’t have everything finalized, but we’re making excellent progress.”