The Gutierrez Co. is staring down a foreclosure at two of its properties at the Middlesex Technology Center in Billerica, in the latest sign that a prolonged economic downturn is taking its toll on commercial real estate owners.

Nationwide Life Insurance Co. filed papers last week in Middlesex Superior Court, asking a judge for permission to foreclose on a pair of Gutierrez-owned buildings in the Middlesex Technology Center.

Nationwide is trying to seize Buildings 4 and 5 at 900 Middlesex Turnpike. The buildings, which total 141,000 square feet, are largely vacant.

Gutierrez ran into trouble when Schott Solar shut down its Billerica manufacturing operations and vacated Building 4 last summer. The 94,000-square-foot property has been vacant since then. The 47,000-square-foot Building 5 is 36 percent vacant. Nationwide is attempting to foreclose on both properties because they are cross-collateralized.

The two properties are secured by two loans totaling $6.1 million. The Gutierrez Co. has yet to contest the foreclosures in Superior Court, a fact that led Nationwide’s attorney to ask for a default judgment last week.

In a statement, Gutierrez Co. president Arthur Gutierrez Jr. said his firm is currently "evaluating alternative options for the properties."

Schott’s former facility has been occupied exclusively by solar users since it was built in 1980, Gutierrez said.

"The facility was built for a specific solar manufacturing process and the cost to readapt it to today’s tenantable standards is cost prohibitive. We remain optimistic that we can work with our lender to find a mutually agreeable solution to this situation," the company said.