Published on September 29th, 2013 | by Tina Casey14
Algae Farm-In-A-Balloon Could Silence The Algae Biofuel Boo-Birds
A company called Proterro has come up with a super low-cost way to squeeze sucrose out of algae, and if its new pilot-scale facility shakes out successfully, don’t be surprised to hear the sound of garment rending and teeth gnashing from the algae biofuel doubters. That’s because a sucrose feedstock simplifies the biofuel refining process on down through the pipeline, leading to lower costs and, well, no more excuses from certain legislators and pundits who have been trying to cut the algae biofuel market off at the knees.
Algae Biofuel And Sucrose
Since the early days of fermenting ethanol from yeast, the biofuel market has grown along a number of different pathways. A couple of examples we’ve been following are OriginOil, which has developed a way to harvest drop-in biofuel from algae, and the Department of Energy’s Joint Genome Institute, which has been exploring an enzyme-based biofuel process.
Proterro (not to be confused with the electric bus company Proterra, btw) has taken an approach that shares some characteristics with another company we’ve been following, Joule. It basically stands the biofuel feedstock process on its head. Instead of extracting a mix of sugars or complex hydrocarbons from biomass, Proterro’s system is designed to produce a single, simple sugar, sucrose.
The significance of that development was aptly described by our friends over at Biofuels Digest back in 2010:
Low cost sugars are cited by all as the technology that will transform the biofuels story from a struggle for viability into a race for epic scale. If petroleum parity is the Holy Grail of biofuels, then cheap sugar is the nectar that fills the chalice.
The Proterro Algae Process
The heart of Proterro’s process is a balloon-like, low-cost photobioreactor, where the company’s patented cyanobacteria are grown with the help of sunlight and carbon dioxide. While conventional algae farming is water-intensive, the system significantly reduces the amount of water needed by growing the cyanobacteria on vertically arranged thin films of a composite fabric.
With the water factor cut down to a minimum, the footprint of the system is small compared to conventional algae farming, which allows for more flexibility in site selection.
The proprietary bug (cyanobacteria are a bacteria, not an algae, though due to their aquatic lifestyle they are commonly known as blue-green algae) has been engineered to “sweat” a sucrose solution, which is collected by gravity. That significantly cuts down on the amount of energy needed to dewater the algae to get at the goodies.
Also reducing costs are the off-the-shelf materials needed to build the photobioreactor, primarily polyethylene for the cylindrical shell.
As for the algae biofuel nay-sayers, over the past few years the US Navy has taken a lot of hot air from certain politicians and pundits over its intensive pursuit of algae biofuel and other renewable fuels, but as the technology improves we’ve been hearing more and more cricket chirps from those quarters.