Could brown seaweed be the next biofuel?

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A scientific breakthrough could see large scale seaweed cultivation to produce renewable fuels.

Many of us will already be familiar with the idea of microalgae (phytoplankton) being used to create biofuels for the future and there is much debate about the feasibility of microalgae, not least the amount of energy that is needed to produce a useable oil from phytoplankton.

So, if not microalgae how about macroalgae or to use its more familiar name – seaweed? Traditionally macroalgae has been passed over as a candidate for biofuel as its primary sugar content is not easily fermented. However, a team of scientists from Bio Architecture Lab (BAL) have reached a breakthrough and engineered a microbe that is capable of extracting all the major sugars in seaweed and convert them into fuel and other chemicals, thus seaweed becomes a cost-effective and renewable source of biomass.

"About 60% of the dry biomass of seaweed are fermentable carbohydrates, and approximately half of those are locked in a single carbohydrate – alginate," said Daniel Trunfio, Chief Executive Officer at Bio Architecture Lab.

"Our scientists have engineered an enzyme to degrade and a pathway to metabolize the alginate, allowing us to utilize all the major sugars in seaweed, which therefore makes the biomass an economical feedstock for the production of renewable fuels and chemicals."

Seaweed could be the ideal feedstock for commercial production of renewable biofuels and chemicals due to both its high sugar content, and a lack of lignin. Seaweed doesn’t need land or freshwater to grow, and it is environmentally friendly.

It gets better, with figures suggesting that seaweed could yield approximately twice the amount of bio-ethanol productivity of sugarcane and five times that of corn. It is estimated that less than 3% of global coastal waters would be needed to replace over 60 billion gallons of fossil fuel.  

"BAL's technology to ferment a seaweed feedstock to renewable fuels and chemicals has suggested an entirely new pathway for biofuels development, one that is no longer constrained to terrestrial sources," says ARPA-E Program Director Dr. Jonathan Burbaum. "When fully developed and deployed, large scale seaweed cultivation combined with BAL's technology promises to produce renewable fuels and chemicals without forcing a tradeoff with conventional food crops such as corn or sugarcane."

BAL’s scientific breakthrough "An Engineered Microbial Platform for Direct Biofuel Production from Brown Macroalgae", appears on the cover of the January 20 issue of Science magazine.

For further information, see the paper: An Engineered Microbial Platform for Direct Biofuel Production from Brown Macroalgae  Adam J. Wargacki, Effendi Leonard, Maung Nyan Win, Drew D. Regitsky, Christine Nicole S. Santos, Peter B. Kim, Susan R. Cooper, Ryan M. Raisner, Asael Herman, Alicia B. Sivitz, Arun Lakshmanaswamy, Yuki Kashiyama, David Baker, and Yasuo Yoshikuni
Science 20 January 2012: 335 (6066), 308-313.

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