Experts have long hoped that the ocean's plentiful stores of seaweed could be turned into renewable biofuels. Now that goal is one step closer: Scientists have engineered a special bacteria to break down the previously inaccessible sugar in seaweed, which can then be transformed into biofuels similar to ethanol. Here's how they did it:

First off: Why seaweed? 
Kelp is appealing as a fuel alternative for several reasons. Environmentally sustainable, it doesn't require farmland or freshwater to grow and it boasts a naturally high sugar content, says Wendy Koch at USA Today. And harvesting the ocean's plant life could produce considerable yields. "Cultivating seaweed along three percent of the world's coastlines, where kelp already grows, could produce 60 billion gallons of ethanol," says Wynne Parry at Live Science.

But why couldn't we harvest it before?
The problem, says Parry, is that one of its primary sugars, alginate, could not be "broken down efficiently enough to produce biofuel on an industrial scale" — until now. Alginate is used in everything from ice cream to textiles, but it "has proved difficult to break down and metabolize into fuel," notes Rachel Ehrenberg at Science News.

What changed?
Scientists from the Bio Architecture Lab headquartered in Berkeley, Calif., genetically engineered a special strain of E. coli bacteria capable of digesting the kelp's sugars into more accessible glucose. The new system is like a "Lego platform," says Parry, because the system's microbial components can be rearranged to produce different types of fuel, like butanol — "an alcohol like ethanol, which is blended into gas" — or even a biodiesel similar to conventional gas. 

So what's next?
"Does this change everything? No," Chris Somerville, director of the Energy Biosciences Institute, tells Live Science. Farming seaweed on an industrial scale raises new industrial concerns, and the process will have to be refined until it's economically viable. What it offers, says Somerville, is "the beginning of opening up a new area."

Sources: Live Science, Science News, USA Today