Royal DSM N.V., a Dutch life and materials sciences company, today made a $1.1 billion cash offer for Martek Biosciences Corp. of Columbia in a deal that represents a 35 percent premium over its stock.

Board members from both companies have approved the acquisition of Martek, a company that was founded in Maryland 25 years ago by a group of scientists who spun off from the Martin Marietta Corp.

The purchase is based on a 35 percent premium of Martek's closing price of $23.36 on Monday. Royal DSM said it would pay $31.50 per share for the company. The transaction is expected to close in the first half of next year.

Martek is a leading provider of infant nutritional supplements and has recently begun expanding the scope of its additives to other categories of products, such as dietary supplements and salad and sub dressings at the Quizno's restaurant chain.

The company produces docosahexaenoic acid, an omega-3 fatty acid, from algal sources, which has been approved for use in infant formula by the U.S. Food and Drug Administration. The additive is found in about 99 percent of infant formula in the U.S., Martek claims.