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Solix and Colorado State University Commercializing New Algae-to-Biodiesel Process

A prototype of the Solix photo-bioreactor for algae production. Click to enlarge.

Solix Biofuels Inc., a startup company based in Boulder, Colorado, is working with Colorado State University engineers to commercialize technology to produce biodiesel from oil derived from algae. Solix officials plan to have the technology on the market over the next two years.

The Solix photo-bioreactors for algae production are based upon 20 years of research (the Aquatic Species Program) originating at the National Renewal Energy Laboratory (NREL), and are massively scaleable, according to the company.

The algae grow within closed plastic bags, which reduces the possibility of infestation drastically. A novel low-energy temperature control system keeps the algae within a temperature range that optimizes growth.

The bioreactor primarily consists of two large transparent flattened tubes made of specialty plastics. Water-weighted rollers squeeze the algae-bearing fluid through the tubes as they slowly move down tracks built into concrete supports on the side of the tubes.

The peristaltic motion of the rollers creates a current inside the reactor, which force the algae to be in constant motion and allows more than just the top layer of algae to receive sunlight.

In turn, that allows the fluid depth of the reactor to be 12 inches, and thus does not restrict photosynthesis to the surface layer of the fluid—a traditional obstacle to making cost-efficient photosynthetic bioreactors.

Within the “bag” is a thermal layer that can be raised or lowered by the rollers to regulate the internal temperature of the bioreactor. The shape of the straps holding the foam is designed to maximize the fluid rotation within the reactor, presenting all the algae sequentially to the sun absorption zone in the top layers of the reactor. CO2 is injected into the photo-bioreactor for the photosynthesis reaction.

Colorado State and Solix officials are collaborating with New Belgium Brewing Co. to use excess carbon dioxide from the brewery’s plant to test the algae-based biodiesel process.

Algae cells are harvested from the fluid with a centrifuge. Once harvested, the oil will be extracted and the resulting oil can then be refined into biodiesel fuels through the same transesterification process currently used to refine other vegetative oil sources into biodiesel. The algae oil can also be refined into other liquid fuels, including ethanol and jet fuel.

Solix officials estimate that widespread construction of its photo-bioreactor system could meet the demand for the US consumption of diesel fuel—about 4 million barrels a day—by growing algae on less than 0.5% of the US land area, which is otherwise unused land adjacent to power plants and ethanol plants. The plants would also supply the requisite carbon dioxide.

Algae to biofuel technologies are still being developed, yet a strong case can be made for global domestication of algae as an energy crop. We want to manage this technology to create a business that will serve current and future energy stakeholders.

—Doug Henston, chief executive officer of Solix



Nice to see another player in this field. The more minds working on it, the greater chance of success.


Not only could we deminish our use of fossil fuels and the resulting CO2 released, we could remove CO2 from the air we breath or stop it's release from other sources that can't be easily run on biofuels. I wonder if someday we might have scrubbers on our cars, not unlike power plants have, to capture the CO2. hmmmm....


How does this system's input/output compare to Green Star's Algae Bi-Reactors that were purchased by South Africa recently (Posted on GREEN CAR CONGRESS 11/14/2006 -- listed under Biodiesel Archive)?? Does anyone have any solid numbers??


Awesome, I drink there beer and hopefully soon I will be able to use there bio diesel. From what I can tell this technology shows the most promise for the fuel future.


There are no productivity numbers on the Solix website.  The design of the greenhouse bag is pretty clever if you ask me, though.


New Belgium Brewing has a history of ecologically freindly (and employee friendly) practices. Their Fat Tire beer is very good. I may make them my prime supplier of beer products for this.

Roger Pham

Good point, Jason,

This is a real promising way to harness solar energy to turn directly into liquid fuel very efficiently, in the least number of steps and lowest pollution. Bio-diesel is sulfur-free and less polluting than diesel fuel.

However, to "scrub CO2 from car's tail pipe", the easiest way is to run the car on hydrogen. Convert the algae biomass into hydrogen via either anerobic fermation or gasification, use the H2 for transportation, and then save the CO2 to feed back into the algae bio-reactor. Recycling most of the CO2 this way is the fastest way to reduce global warming while become energy self-sufficient. The remaining byproduct of fermentation can be recycled back into the bioreactor as natural fertilizer. A micro-biosphere!

Thus, killing 2 birds with one stone! Wait...H2 transportation is incredibly clean in comparison the diesel exhaust that has been shown to cause increase deaths in Europe due to lung cancers and respiratory ailments...So, killing 3 birds with one stone!!! CARB should be real pleased to hear this!


_Nice, recycle the plastic after the UV degrade it...unless it has a UV coating. OTOH, wear and tear will necessitate replacement after a while.
_This design seems relatively cheap, compared to other bioreactors. The rollers may a significant operational cost, in energy, $, and maintenance. A small solar panel mounted above the roller, might reduce those costs a bit. Since the rollers already cast shadows, it would not block additional light to the algae.
_One question would be how well does this stand up to hail and sandstorms?

Pat O

I suppose the rollers could be fitted with some type of "snowshovel" if you're worried about debris/sand inhibiting light penetration into the bags.

This is a very cool design. I like the idea of running the rollers on photovoltaics if possible. Or they could be turned using the CO2 exhaust prior to it entering the photobioreactors.


I'm probably the biggest algae to oil fan on here, but I still think the whole transesterification to biodiesel process is lossy. The required ethanol (or methanol) has to come from somewhere, and that would take a lot more land (or coal/oil whatever) to provide. Just use the SVO directly I say (and do)! Also, scrubbing atmospheric CO2 rather than power plant CO2 is the ideal end goal of the algae -> oil programme.

Incidentally, for the home-growers among you, a backyard version of these strips (say 20 m2) should yield about 50 gallons per year from your own back garden, enough to run your SVO-PHEV all year with no trips to the fuel pumps!

Ran Macdonald

I would like to know if ambient air could be used to grow the algae instead of pure CO2. Could you move air through the algal mass at high volume?


If you want to see algae grow, put an inflatable a kids swimming pool in the back yard and cover it with a clear poly sheet. With no chlorine, the pool will be blue green with algae within a few weeks.


I go through 50 gallons per week...

I am also a huge algae to oil fan. I actually had an idea very similar to this about 6 months ago. No joke. I'm actually thinking about calling Solix to see if I could work with/for them.


We need to be realistic. As a civilization, we aren't going to make one huge step and become carbon neutral. It's just not going to happen. Instead we have to make gradual steps.

Let's just say that, in theory, the amount of CO2 emitted by coal fired plants in the U.S. is enough to feed enough algae to meet the U.S. demand for diesel on a per anum basis. While we wouldn't be carbon neutral, we would be emitting a lot less CO2 (30% sound fair?)

The next step would be to transition the entire U.S. to diesel (good luck, I know). That would also result in a substantial CO2 cut.

Another thing would be a massive implementation of hydrogen injection (check out MIT's plasmafication... thing... that is supposed to come to market in 2010). Widespread use would result in another CO2 cut.

The three things mentioned above would probably cut our CO2 output by 50% and they are all very achievable. This will at least slow down our environmental spiral and buy us time to develop the technologies and infrastructure that could make civilization CO2 neutral.

Interesting idea about burning the SVO to produce electricity to produce hydrogen and CO2. The CO2 could be dumped back into the algae as a fertilizer and the hydrogen could be used as a fuel. If you did it the right way, maybe, just maybe, you could balance the CO2 in out and essentially use the algae as a big, super efficient and cheap, solar panel.

That right there is the type of thinking that could change the game... now if we could only store hydrogen...

Roger Pham

Hi John,

"That right there is the type of thinking that could change the if we could only store hydrogen..."

U r almost on the right track. We can store hydrogen, but only in limited amount. So, store the algae biomass, and ferment it or gasify it into H2 just fast enough to keep up with the H2 transportation demand. Or, simply combust the H2 at the power plant to produce electricity would make it even simpler, until the H2-vehicle fleet will arrive in sufficient number.


how the heck do they harvest the algae out of the bag? doesnt it stich to the sides?


probably can't stick if it's in constant motion, and to get it out I would guess it can be pumped through an extraction system that would grab the larger algae and send back the small ones, then further sorted by centrifuge


There is no doubt that systems such as this combined with other more traditional systems are steps in the right direction. It will be the combination(s) of tecnologies that will result in the pay-off that we need to reduce our dependence on petroleum as a fuel.
The modern technological society we have must find ways to reduce the consumption of oil products as fuels and find ways to recycle the oil products that we now create daily.

Craig Mackintosh

Algae-to-Biodiesel looks a lot more sustainable than the current 'solutions'.
Does anyone know why "two years" yet? What's the hold up? (The pressure is mounting).

Cheryl Ho

There are developments in DME in China today:
DME is an LPG-like synthetic fuel can be produced through gasification of Biomass. The synthetic gas is then catalyzed to produce DME. A gas under normal pressure and temperature, DME can be compressed into a liquid and used as an alternative to diesel. Its low emissions make it relatively environmentally friendly. In fact, Shandong University completed Pilot plant in Jinan and will be sharing their experience at upcoming North Asia DME / Methanol conference in Beijing, 27-28 June 2007, St Regis Hotel. The conference covers key areas which include:

DME productivity can be much higher especially if
country energy policies makes an effort comparable to
that invested in increasing supply.
National Development Reform Commission NDRC
Ministry of Energy for Mongolia

Production of DME/ Methanol through biomass
gasification could potentially be commercialized
Shandong University completed Pilot plant in Jinan and
will be sharing their experience.

Advances in conversion technologies are readily
available and offer exciting potential of DME as a
chemical feedstock
By: Kogas, Lurgi and Haldor Topsoe

Available project finance supports the investments
that DME/ Methanol can play a large energy supply role
By: International Finance Corporation

For more information:

Khurram Riaz

This is very nice & informative site & keep updated me.thanks



National Algae Association
4747 Research Forest Dr., Suite 180
The Woodlands, Texas 77381
[email protected]

National Algae Association, The Woodlands, Texas
(February 1, 2008)

Announces the opening of its new headquarters serving all areas of the Algae industry.

Algae researchers and producers can come together to exchange ideas concerning the latest developments in Algae production and the products made from Algae. The Association provides an open exchange forum for the publishing of technical papers and the announcement of the results of research into the latest Algae related technologies. The Association also supports discussion and development of new markets that take advantage of the tremendous potential of Algae, not only as a source of renewable energy, but also in the exploration and development of other markets for algae products, such as cosmetics, pharmaceuticals and fertilizers.

For more information contact: [email protected] or 936.321.1125

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