British investment fund Terra Firma is interested in buying Viterra, the huge real estate arm of German energy giant E.ON, the head of Terra Firma's German operations, Georg Kulenkampff, said in a newspaper interview published Tuesday. Viterra is said to be worth €5-6 billion (6.5-7.8 billion dollars) and only three or four companies were seen as serious bidders, the Financial Times Deutschland reported. "There aren't many who would be able to put up such money," but Terra Firma was one of them, Kulenkampff told the newspaper. With around 150,000 residential properties, Viterra is one of the biggest owners of private real estate in Germany. Terra Firma recently acquired German motorway service station operator Tank und Rast for just over €1billion.