Twenty-five years ago, fast-growing Monsanto Co. christened a new research campus in Chesterfield.

On Monday, a reincarnation of the same company reclaimed the property for $435 million.

Monsanto's plans to buy the Chesterfield Village Research Center from Pfizer Inc. helps ease a space crunch at the company's Creve Coeur headquarters and paves the way for the biotech giant to further expand its research and development arm, which will invest about $1 billion this fiscal year developing new corn, cotton and soybean seeds.

"St. Louis is already a home to a large percentage of our R&D activity, and this allows us to consolidate our capabilities here and eventually expand them," Robb Fraley, Monsanto's chief technology officer, said in an interview.

Local economic development officials said the announcement also helps cushion the blow of 600 local jobs being eliminated by Pfizer, the property's current owners, following its merger with pharmaceutical giant Wyeth.

"That is a huge saving grace with the prospect of significant growth in the future from the Monsanto side of the ledger," said Dick Fleming, executive director of the St. Louis Regional Chamber and Growth Association.

Details of Monsanto's plans for the Chesterfield campus are still vague. The company anticipates moving some of the 700 researchers who work at the Creve Coeur campus to Chesterfield after some renovations are complete. But it's too soon to know how many employees will be transferred, or when, Fraley said.

"I would hope that over the years as we grow and transition and migrate folks from Creve Coeur, this will meet our long-term head count needs for many, many years," he said.

The Chesterfield campus can accommodate about 1,000 researchers. But it's not yet clear when the company will add jobs to help the St. Louis area ease the sting of the job losses at Pfizer and other layoffs that have contributed to a rising unemployment rate.

Monsanto itself eliminated about 8 percent of its global work force, or 1,800 employees, in recent months, including about 300 in the St. Louis area. There are currently 4,000 Monsanto employees in the St. Louis area.

Still, Monsanto has added about 10,000 jobs globally over the last five years, and its research arm remains the lifeblood of the company. Last week alone, the company announced its first research center in China and broke ground on a new cotton research facility in Lubbock, Texas.

Chief Executive Hugh Grant is banking on innovative new products such as drought-tolerant corn and higher-yielding soybeans to help it fulfill its promise of doubling grain yields by 2030.

"Our R&D organization is continuing to grow a pipeline of new products, and we're going to need to expand our capabilities and our staffing," Fraley said.

The Chesterfield campus is home to 1.3 million square feet on 210 acres. Its seven buildings include 250 labs, two acres of rooftop greenhouses for growing corn, cotton and soybeans, and more than 120 plant growth chambers where scientists can simulate any growing environment.

The campus was developed by the former Monsanto Co. for about $150 million in the early 1980s. At the time, Monsanto was engaged in agriculture and pharmaceutical research.

In 2000, Monsanto merged with Pharmacia & Upjohn Inc. Two years later, Pharmacia spun off the new Monsanto, which today is focused solely on agricultural biotech. Pfizer bought Pharmacia in 2003.

While Monsanto gave up ownership of the Chesterfield campus in 2000, it has continued to lease about 400,000 square feet, and the lease continued after Pfizer acquired Pharmacia in 2003. More than 400 Monsanto employees and contractors work on site, mostly researchers.

The landlord-tenant role will be reversed after the sale, which is expected to be complete during the first half of 2010; Pfizer will continue to have operations on the campus through a lease agreement with Monsanto. Additional terms weren't disclosed.

Steve Giegerich of the Post-Dispatch contributed to this report.