* Investor AB pays 510 million euros for 34 percent stake
* Buys stake from Morgan Stanley
* Purchase adds to healthcare portfolio (Adds quotes, background)
STOCKHOLM, Aug 26 (Reuters) - Swedish holding company Investor AB is raising its stake in healthcare group Molnlycke to 96 percent, adding to its health portfolio after the purchase in July of Aleris.
Investor, the investment vehicle of Sweden's powerful Wallenberg business family, said on Thursday it had agreed to pay 510 million euros to buy 34 percent of Molnlycke from Morgan Stanley.
Investor said the purchase valued Molnlycke at 3.2 billion euros.
Investor and Morgan Stanley went into Molnlycke together in 2007, buying the group from Apax Partners for an enterprise value of 2.85 billion euros.
Investor has been gradually increasing its stake in the firm. It said in its most recent quarterly report that Molnlycke revenue growth was solid and that profits continued to grow at a high pace.
(Reporting by Patrick Lannin; Editing by Erica Billingham)