Farm Futures reports that venture capital firms more than doubled their investments in biofuels and other energy ventures in 2006, and even more is expected in 2007.

According to DowJones Venture One, firms put $224 million towards energy ventures in 2005 – and $536 million in 2006’s first three quarters alone. Another estimate, by venture-capital firm Nth Power, puts the amount invested in energy start-ups at a whopping $1.7 billion in 2006. Start-ups making biofuel from farm products took the biggest share, the firm says.

Biotech firms working on more efficient ways to produce biofuels also saw a big boost in 2006. For example, the Miami Herald reports that shares of Florida-based Dyadic International were up 205 percent in 2006.

This Jupiter company has a ton of buzz words going for it, including biotech, DNA sequencing and cheap alternatives to oil. It’s signed a contract with a Spanish energy giant, Abengoa, to build a plant that would convert plant waste into fuel in a much cheaper way than corn-based ethanol. The company, which has a research relationship with Scripps Florida, is also developing enzymes to lower production costs of paper, textiles and animal feed.