Already the world's largest oil refining and exploration company, Exxon became the largest gas producer on the planet when it acquired Texas-based XTO Energy in June for $31 billion. Meanwhile, the company's chemicals business, with revenues of $41 billion, is second only to Dow in the U.S. Now the oil giant is making a big push into alternate energy. This summer it invested $600 million to develop a biofuel refined from algae with Craig Venter's Synthetic Genomics.
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