Could the Sea Squirt Be a Bountiful Biofuel Source?

What to do with invasive species has been a perennial discussion in the environmental community. Some have suggested that in places where they have become an ecological menace we should be eating them out of existence. Now researchers in Norway say that one invasive species in our oceans is ideally suited for biofuel production, and rather than stomping them out, we should be growing more of them.

Though far from any sort of commercial-scale production, scientists from the University of Bergen and Uni Research say that Ciona intestinalis, a type of sea squirt called the vase tunicate, can be cultivated, pressed and turned into ethanol.

The vase tunicate is particularly well-suited for biofuel production, the researchers say, because it has a high yield (up to 200 kg per square meter of ocean area). Unlike any other creatures in the animal kingdom, tunicates produce cellulose, which they use to construct the walls of their body. It might be hard to believe based on their noodle-like appearance, but tunicates are actually considered a sister sub-phylum to us vertebrates.

A method similar to mussel cultivation is used to farm the tunicates. Long plastic sheets are anchored to the sea floor and held up vertically with buoys. The seawater flowing between the sheets contains the microorganisms that the tunicates eat.

After harvesting these tunicates, the water that makes up 95 percent of their body mass has to be removed. The cellulose that makes up the walls of their bodies could then be broken down into sugars, which in turn can be used to make ethanol. Technically this would be a second-generation biofuel, in the same way that making cellulosic ethanol from wood chips and yard waste is—except of course that it's an animal being raised specifically for the purpose of being fuel.

Should the vase tunicate ever be commercially cultivated for biofuel production—a far from certain thing at this point—it would be the first animal grown specifically to power our cars, though it wouldn't be the first time that an animal product was used. Setting aside petroleum's prehistoric origins, a number of major food companies have proposed using animal fat waste from factory farms and slaughterhouses as a feedstock for biofuels.

Tyson Foods and Syntroleum, under the Dynamic Fuels name lead the charge to turn animal fat into diesel fuel. For several years now, this animal fat biodiesel has been used by the US Navy as part of its Great Green Fleet biofuel experiments, and earlier this year, Mazda used it in the Rolex 24 endurance race at the Daytona Speedway.

Tunicates would not even be the first invasive species to be turned into biofuel. For the past several years, researchers have been working on turning kudzu into ethanol—although no one is proposing growing the vine that ate the South specifically for biofuel, just harvesting as much as can be from areas where it now grows naturally.

Driving around powered by sea-creature combustion might be old hat, but a tunicate spill in the gulf sure seems preferable to what we have now, if unlikely.