HEERLEN, Netherlands ( TheStreet) -- Dutch chemicals company DSM offered to buy Martek Biosciences ( MATK) for $31.50 a share, or $1.09 billion in cash. DSM said Tuesday the offer is a 35% premium to Martek's closing price Monday of $23.36. The board of Martek, a biotechnology company, recommended shareholders approve the offer. DSM, a maker of vitamins, said the acquisition adds a new growth platform for polyunsaturated fatty acids nutrition ingredients and strengthens its position in the United States, particularly in infant formula nutrition. DSM said the acquisition is expected to close in the first or second quarter of 2011. It will be immediately accretive to per-share earnings, DSM said. -- Written by Joseph Woelfel >To contact the writer of this article, click here: Joseph Woelfel >To submit a news tip, send an email to: email@example.com.