New Algae Biofuel: Holy Hot Sugar, Batman! | 20/02/14
by Tina Casey
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.
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 demonstration scale 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 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.
About the Author
Tina Casey 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. You can also follow her on Twitter @TinaMCasey and Google+