August 21, 2009
Algae Strain Uses CO2 Under High Light Conditions
Algae for biomass energy are getting bred for higher productivity.
Today, Aurora Biofuels announces a technological milestone in the company's path to becoming the premier producer of low-cost advanced biofuels. Through a series of biotechnology achievements, Aurora has succeeded in optimizing its base algae strains to more than double CO2 consumption and fuel production, and has proven these results in an outdoor open system over the last several months.
Using tools developed in the fields of molecular biology and biochemistry, Aurora Biofuels scientists have developed a proprietary process which allows for the superior selection and breeding of non-transgenic algae. With this novel technique, the company has optimized its base algae strains with an increased ability to process sunlight and carbon dioxide into algal oil. As a result, these algae strains can produce more than twice the amount of oil. Optimized algae have been producing oil in Aurora Biofuels' outdoor pilot ponds for several months, providing strong evidence that these strains will remain robust at the industrial scale and remove more carbon emissions than previously thought possible.
What I find most interesting about this report: They are selecting for algae that yield the desired result. They aren't doing genetic manipulations. They are just selecting between existing mutations. Selection can certainly yield greatly improved strains. Look at the breeding programs for better crops and how much these programs have revolutionized agriculture in the 20th century. But I suspect that too many changes to algae are needed to make algae suitable for low cost fuel production. Selection will get us part of the way there. But my guess is that genetic engineering will be needed to get us all the way there.
Some labs are working on genetic manipulations on algae. The big decline in DNA sequencing costs and DNA and RNA testing costs will speed up the identification of genes and what they do. Then the returns on investment for doing genetic manipulation for biomass energy will go up.
The company selected for algae that keep incorporating carbon dioxide under the more intense sunlight of high noon.
“Algae have a built-in mechanism to be effective at low light and as it gets brighter during the day their uptake of carbon dioxide levels off,” said Mr. Walsh. “We’ve been able to go in and alter strains by natural mutation to cause the algae to deal with light across the whole spectrum. The algae continue to uptake CO2 through brighter light and are more productive.”
The rate of growth of algae is just one of several factors that affect biodiesel algae costs. Another big factor is extraction cost. What does it cost to get the oil separated from the rest of the algae mass?
What I'm wondering: Will highly optimized strains be at a competitive disadvantage to unoptimized strains? Will contamination by natural wild type strains ruin open air growing ponds? It might become necessary to put genes into the oil production strains that allow them thrive under circumstances (e.g. in presence of a toxin) that will kill or hobble wild type strains. Kinda like how Roundup ready crops are resistant to the herbicide Roundup.
Extracting the oil from algae has been expensive so far:
But because algae is rich in oil, it can also be burned directly in exactly the same power plants that burn coal, with the extra advantage that there will be no need for expensive equipment to filter out heavy metal pollutants or CO_2. Once the algae is dried, it can be shipped in solid form by train. This is very significant for electric cars and also for heating. Thus algae would be very useful for burning instead of coal.
By the time algae oil extraction is made economically competitive, electric car batteries will be advanced enough, so that the main advantage of liquid algae oil will be for jet fuel (crucial), and also for military vehicles that might need traditional liquid fuel.
You'll never see these press releases talk about sustained system photosynthetic efficiency because as soon as they do, it is clear they can't build systems cheaply enough to be paid for by their efficiency in converting photosynthetically active radiation to salable energy. I've been looking at this problem for a long time and it is clear that even with some serious invention -- no-prior-art patent type invention -- you can barely make a system that will actually pay for its costs (capital and operation) even selling algal protein at the price-equivalent of alfalfa protein, which is about twice the value of diesel per mass.
BTW: They are barking up the wrong tree anyway since you can overcome the photo-saturation problem with self-shaded turbulence that comes relatively cheaply in terms of return on energy.
Drying algae is a huge energy sink in itself. Engineering the algae to secrete oil which is skimmed off is one way around the separation problem. Breaking down bulk wet algae in supercritical water to make simpler molecules is another.
But none of this matters. Even if the process itself can be made cheap, you still need to feed enriched CO2 to it. Any viable system has to get its own CO2 from the atmosphere or it's not going to be able to afford feedstock.
Genetic engineering requires all kinds of licenses. Selective breeding does not. That is a huge cost saving and the it allows a test phase in which algae can be tested if they stay stable.
I believe the plan is to use the CO2 output of a electricity plant.
Could see it useful in space, for the rest i have my doubts.
Using the CO2 output of a fossil-fired powerplant doesn't work if CO2 emissions are restricted. The loop needs to be closed or the scheme is vulnerable to legal as well as technical uncertainties.
The whole point of attaching an algae plant to a fossil fueled powerplant is that it IS the method of reducing carbon emissions. Its a win-win: the powerplant reduces its carbon emissions to standards, and at the same time produces salable goods, whether it is feed for livestock, pharmaceuticals, or biofuel. As more stringent carbon limits are passed, algae plants will become more viable simply because large carbon producers will pay out the ear to have their emissions reduced.