By Katya Golubkova and Denis Pinchuk

ST PETERSBURG, Russia (Reuters) - Russian billionaire Gennady Timchenko, co-owner of Gunvor, wants to transform his fast-growing trading house into an integrated oil company by expanding production and refining after having already bought two plants in Europe this year.

Timchenko told Reuters on Thursday he believed it was the right time to buy downstream assets but added Gunvor was not yet ready for big oil producing purchases.

The comment followed market speculation Timchenko could try to buy 50 percent in TNK-BP, Russia's No.3 oil firm, after British oil major BP put it up for sale amid a dispute with its partners, a consortium of four Soviet-borne billionaires.

"It (TNK-BP) is a very big company, we are not ready for such big purchases, we did not even discuss this subject," Timchenko said in a rare interview.

"We have become active in buying oil refineries now as we think that now is the right time to enter oil refining," he said on the sidelines of the St Petersburg International Economic Forum.

Gunvor has this year bought bankrupt Swiss oil firm Petroplus's refinery in Ingolstadt, Germany, and a plant in Antwerp, Belgium.

Timchenko said Gunvor may look at other "interesting possibilities" in downstream if they arose.

Timchenko, viewed as having good relations with Russian President Vladimir Putin, said he owns just over 46 percent in Gunvor. Chief Executive Torbjorn Tornqvist owns 46 percent, while the rest is owned by management.

He said he would not be able to predict Gunvor's profit for this year because of volatile oil prices but added the trader usually posts profit between $300-$400 million a year on a turnaround of around $86 billion.

"I think it is normal revenues for our industry, maybe even slightly lower than the others," he said.

(Editing by Douglas Busvine and James Jukwey)