Published on February 19th, 2014 | by Tina Casey


New Algae Biofuel: Holy Hot Sugar, Batman!

February 19th, 2014 by  

When we say hot sugar, we mean a new generation of low cost industrial sugars that could help pull the biofuel market out of dependence on conventional crop based sugars. That leaves the field clear for the algae biofuel sector, and that’s where things start to get interesting.

A company called Proterro came across our radar last fall for just such an approach, which basically turns the first-generation biofuel model on its head. Instead of taking apart plants to extract sugars for processing into biofuel, Proterro has figured out a way to get a micro-algae called cyanobacteria to secrete the “hot sugar” sucrose.

algae biofuel

Industrial sugar production from cyanobacteria Courtesy of Proterro

A Different Approach To Algae Biofuel

It’s worth noting up front that there are already several promising cost-effective pathways to extracting oils directly from algae and microalgae (here, here, and here for example), but there is plenty of room in this emerging fuel market for something different, namely, using algae to produce a sugar feedstock for fermentation into fuels and other products.

Also, for the record, cyanobacteria is commonly referred to as blue-green algae, but as its formal name indicates, it is actually a bacteria and not a form of marine plant life.

When we covered the news from Proterro last fall, the company had already won a US patent for its proprietary strain of cyanobacteria. In the latest development, Proterro has obtained a notice of allowance from the US patent office for the structural platform — a photobioreactor — that enables the bacteria to produce sugars at a highly efficient rate, in a process that uses carbon dioxide, sunlight, and water.

The Proterro Photobioreactor

According to Proterro, the photobioreactor is 30 times more productive than sugar cane, on an acreage basis, in terms of producing a “fermentation-ready” stream of sucrose.

That translates into a lower cost for sugar production, and part of the reason for that savings is the aforementioned photobioreactor.

Resembling a big earthbound balloon from the outside, the photobioreactor is actually a sturdy (withstanding Force 1 hurricane winds) built environment made from off-the-shelf materials.  Instead of using vats, pipes, or horizontal cultivating beds, the cyanobacteria grow on vertical fabric walls.

Before we move on let’s pause here and thank our friends over at Biofuels Digest for introducing us to the phrase “hot sugar.” Who knew?

Biofuels and Carbon Dioxide Capture

If a bell went off in your head when you saw carbon dioxide mentioned in the context of biofuels, you are in good company.

With a pilot facility under its belt in Florida, Proterro is already prepared to scale up and hook up with carbon dioxide emitters to feed its cyanobacteria. Utility companies and ethanol plants seem to be tops on its list, but there are numerous other opportunities out there for using microorganisms to capture industrial waste gasses and convert them into useful products.

A New Zealand company, for example, is already active in the field of capturing and converting emissions from steel mills.

That approach makes a lot more sense than some of the other carbon sequestration strategies under discussion these days, namely pumping it underground.

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(readers please note: this post has been updated: the facility is a pilot and ethanol plants are another potential CO2 source).

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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.

  • Nick Mitsis

    Great post, Tina and very timely with environmental regulations heating up in DC. We are following the the algae biofuel sector closely.

  • Ronald Brakels

    Here’s an idea. A producer of alcoholic beverages could reduce their feedstock costs by gathering the CO2 released by fermentation and using that to feed sucrose secreting cyanobacteria. By using sunlight directly instead of indirectlly they could reduce their need for agricultural products by anything up to a third.

  • Rick Kargaard

    It had a occured to me recently, that it might be possible to mimic nature and use life forms to convert CO2 to oxygen and carbon fuels. Sounds perfect if it can be scaled. A possible net zero solution.

  • Ronald Brakels

    Now that’s a neat idea, getting the cyanobacteria to spit out sucrose. Of course it makes for problems keeping the tank clear of anything that wants to have a sugar party in there, but that sort of problem is nothing new. Now if the sucrose produced is being used as a feedstock for fermentation, then obviously there is going to be a source of CO2 right there bubbling up from the fermentation tank. Of course it won’t be sufficient. For every six carbon atoms that goes in as sugar you’ll only get two out as CO2 for ethanol production, but it’s still one third of the CO2 required. Also the sucrose couldn’t be used directly in fuel cells but it would need to be concentrated as it would be quite dilute.

  • Kevin McKinney

    “That approach makes a lot more sense than some of the other carbon sequestration strategies under discussion these days, namely pumping it underground.”

    Maybe. Underground storage seems to have its issues. But if the CO2 used to create the biofuel is from fossil sources, I’d much prefer that it *not* end up in the atmosphere.

  • Steve Svensson

    Don’t imagine any of the dangerous toxins the bacteria produce gets into the fuel. People will do anything to stay away from electric cars fueled by solar power.

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