UPDATE 2-Copersucar, Eco-Energy to form world's top ethanol trader

* Two firms to produce 10 bln liters ethanol per year

* U.S., Brazil eye more collaboration on ethanol

SAO PAULO, Nov 5 (Reuters) - Brazil's Copersucar SA is taking control of United States-based Eco-Energy to become the world's largest ethanol trader with a 12 percent share of the global market in the biofuel, the company said on Monday.

The deal deepens an emerging partnership between the world's two top ethanol producers: the United States, which makes corn ethanol, and Brazil, a pioneer in the production of biofuels from sugar cane.

Diversifying into corn-based ethanol helps Copersucar, the world's top sugar exporter, ensure a constant supply, lessening risks during years the center-south cane belt receives too much or too little rain.

``Copersucar will be the first in the world to have a complete ethanol portfolio and actively participate in global ethanol sales,'' Copersucar's Chief Executive Roberto da Souza said on a conference call.

Together Eco-Energy and Copersucar will produce 10 billion liters (2.64 billion gallons) per year of ethanol distilled from sugarcane and corn, up from the 4.8 billion liters of sugar ethanol Copersucar expects to produce in the 2012/13 crop year.

Copersucar, which has delayed a planned initial public offering, declined to give financing details or disclose the precise size of Copersucar's stake in Eco-Energy, citing a confidentiality agreement.

``Last Thursday we concluded an investment process in the U.S. firm Eco-Energy and the result is that the trading firm will be controlled by Copersucar,'' said Luis Roberto Pogetti, President of Copersucar's board of directors.

He said Eco-Energy's current investors would see their shares diluted, however.

By acquiring Eco-Energy, Copersucar will increase its ethanol exports to Europe and plans to double Eco-Energy's operations in the United States in the next three years, he said.

Though a steep tariff on foreign biofuels poisoned U.S.-Brazil ethanol relations for years, collaboration has improved since Washington ended the tax and also allowed a subsidy for U.S. producers to expire this year.

The two countries are working to make ethanol a globally traded commodity, like oil, and the private sector is reaching across borders to create more-efficient biofuels.

Brazil's cane-based ethanol is seen as a more fertile ground for innovation, while U.S. companies have more resources for research and development.

Brazil is typically the world's largest exporter of cane-based ethanol, shipping around 3 billion liters a year. It uses 23-28 billion liters for its domestic flex-fuel car fleet.