Berkeley scientists convert seaweed into ethanol using E. coli

seaweedSugar cane and corn may soon be sharing the biofuel spotlight with a new contender: seaweed. A new breakthrough to break down sugars in seaweed may make the abundant marine algae central to replacing fossil fuels.

The breakthrough is credited to scientists from the Berkeley-based Bio Architecture Lab, Inc (BAL). According to the Scientific American, the BAL researchers used a genetically modified version of Escherichia colito (E. coli) to digest and convert seaweed into fuel and chemical compounds. Their findings have been reported in the January 20 issue of the Science journal.

The reason for the engineered microbe is that industrial microbes cannot digest alginate, the main sugar in brown seaweed. As BAL co-founder and synthetic biologist Yasuo Yoshikuni said, “the form of the sugar inside the seaweed is very exotic.”

So, Yoshikuni and the BAL researchers decided to look into a microbe that could digest the alginate called Vibrio splendidus. They then isolated the genes carrying the desired traits and placed the DNA into the E.coli. To test the new version of the stomach bacteria, the researchers mixed it up with some ground seaweed and a little water and let it stew for two days. The scientists found that the solution yielded 5 percent ethanol and water in temperatures between 25 and 30 degrees Celsius. Yoshinkuni believes that ethanol is just the start and that the microbe could also be used to turn seaweed into a variety of molecules; isobutanol, for example.

Seaweed could be an ideal for biofuel as it seems to be low maintenance; it requires no watering or fertilizer, and nutrients are drawn from the ocean. Jonathan Burbaum, program director at the US Department of Energy’s ARPA-e, points out that seaweed could address land concerns as well, since the algae grows naturally in the “two thirds of the planet that we don’t use for agriculture.” Burbaum says a portion of the agency’s funding will be used to test out the viability of seaweed with a small aquafarm experiment.

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