ceres.jpgCeres, a Thousand Oaks, Calif. company seeking ways to produce plant biomass more efficiently for use in a new generation of alternative fuels, has raised a $75 million in financing.

Ceres has studied and collected sequenced plant genes to find fuels for cellulosic ethanol production, in order to create a more efficient and cleaner version of ethanol — which it hopes will replace gasoline as a transportation fuel. It’s just one several well-backed companies pursuing this.

Ceres works with switchgrass, sorghum, miscanthus, energycane and other woody species. One of its first seed products, a high-yielding switchgrass cultivar, is scheduled for commercial launch in 2009.

The financing was led by Warburg Pincus, and was made in the form of debt that will later convert into stock.

The company has previously raised $77 million including from Artal Luxembourg, Oxford Bioscience Partners, GIMV, H&Q, KBC, Monsanto Co., Oppenheimer Funds, QuestMark Partners, Towerbrook Capital Partner and Soros.

Back in 2001, the company’s private value was nearly $200 million, but no word on what it is now.