Algae has a competitor coming for bio oil – diatoms have the potential to compete and may have a list of problems to price parity with petroleum that is different and may be less challenging.

The leading reasons behind diatom research are:

Geologists claim that much crude oil comes from diatoms.
Diatoms do indeed make oil.
Agriculturists claim that diatoms could make 10−200 times as much oil per hectare as oil seeds.
Therefore, sustainable energy could be made from diatoms.

NaVicula a Diatom with an Oil Droplet.  Click image for more.

NaVicula a Diatom with an Oil Droplet. Click image for more.

Richard Gordon of the University of Manitoba and T. V. Ramachandra, Durga Madhab Mahapatra and B. Karthick of the Centre for Ecological Sciences/Centre for Sustainable Technologies, Indian Institute of Science, Bangalore, India published a paper ‘Milking Diatoms for Sustainable Energy: Biochemical Engineering versus Gasoline-Secreting Diatom Solar Panels.’ The paper proposes ways of harvesting oil from diatoms, using biochemical engineering and also a newly conceived solar panel approach that utilizes genomically modifiable aspects of diatom biology.

The “milking” comes from diatom’s natural oil secretion that offers the prospect of “milking” diatoms for sustainable energy by altering them to actively secrete oil products.  Secretion by and milking of diatoms may provide a way around the puzzle of how to make algae and other single cell based production that both grow quickly and have a very high oil content.  There is a genome to mine here.

The paper discusses a problem that runs through the cell based oil production efforts saying,

“Generally, cell proliferation seems to be counterproductive to oil production on a per-cell basis, which is a problem that has been expressed as an unsolved Catch-22. However, this balance may shift in our favor when we start milking diatoms for oil instead of grinding them.” —Ramachandra et al.

While diatoms and algae are virtual brothers, diatoms are silica based shelled creatures.  That aspect offers, as the paper outlines, a variety of harvesting techniques.  Gordon explains diatoms are barely one-third of a strand of hair in diameter; they flourish in enormous numbers in oceans and other water sources. They die, drift to the seafloor, and deposit their shells and oil into the sediments. Estimates suggest that live diatoms could make 10-200 times as much oil per acre of cultivated area compared to oil seed plants.

The paper covers the potential this way:

“The transparent diatom silica shell consists of a pair of frustules and a varying number of girdle bands that both protect and constrain the size of the oil droplets within, and capture the light needed for their biosynthesis. We propose three methods: (a) biochemical engineering, to extract oil from diatoms and process it into gasoline; (b) a multiscale nanostructured leaf-like panel, using live diatoms genetically engineered to secrete oil (as accomplished by mammalian milk ducts), which is then processed into gasoline; and (c) the use of such a panel with diatoms that produce gasoline directly. The latter could be thought of as a solar panel that converts photons to gasoline rather than electricity or heat.”

Ready for some light confusion?  The authors note that milk is not harvested from cows by grinding them up and extracting the milk, they propose that diatoms essentially be allowed to secrete the oil at their own pace, with selective breeding and alterations of the environment maximizing production.

“Mammalian milk contains oil droplets that are exocytosed from the cells lining the milk ducts. It may be possible to genetically engineer diatoms so that they exocytose their oil droplets. This could lead to continuous harvesting with clean separation of the oil from the diatoms, provided by the diatoms themselves.  Higher plants have oil secretion glands, and diatoms already exocytose the silica contents of the silicalemma, adhesion and motility proteins, and polysaccharides, so the concept of secretion of oil by diatoms is not far-fetched.”

The oil itself is truly bull’s-eye stuff.  The diatoms the authors have seen have oil production in the range of C7-C12 hydrocarbons, about 1/3 of tested diatoms produced α, β, γ, and δ-unsaturated aldehydes.

“With some optimism about the power of systems biology and how malleable microalgae might be, perhaps we could engineer diatoms that would make these compounds, or the lower-molecular-weight alkanes and alkenes, in great quantities.  Given that pathways exist for the production of many alkanes, starting with 12-alkane, the production of shorter alkanes within genetically manipulated diatoms might be plausible. If not, we could fall back on known organic chemistry reactions to convert the natural products to alkanes.”

With more than 200,000 species from which to choose, and all the possible combinations of nutrient and genome manipulation, finding or creating the “best” diatom for sustainable gasoline will be challenging.

The authors offer up some basic guidelines for starting the species hunt:

  • Choose planktonic diatoms with positive buoyancy or at least neutral buoyancy.
  • Choose diatoms that harbor symbiotic nitrogen-fixing cyanobacteria, which should reduce nutrient requirements.
  • Choose diatoms that have high efficiency of photon use, perhaps from those that function at low light levels.
  • Choose diatoms that are thermophilic, especially for solar panels subject to solar heating.
  • Consider those genetics that have been demonstrated by paleogenetics that have contributed to fossil organics.
  • For motile or sessile pennate diatoms that adhere to surfaces, buoyancy may be much less important than survival from desiccation, which seems to induce oil production. Therefore, the reaction of these diatoms to drying is a place to start. The reaction of oceanic planktonic species to drying has not been investigated, although one would anticipate that they have no special mechanisms for addressing this (for them) unusual situation.
  • Genetic engineering of diatoms to enhance oil production has been attempted, but it has not yet been successful.

That’s a good beginning, a place to start.  The list of guides also makes clear the huge variety of diatom genetics.  The potential is factually non-calculable for now.

The innovative thing here is the author’s “head’s up” to look outside the algae field and into other species that offer oil production. While algae may be way further down the development road, there is a lot of road left to go.  Diatoms may well offer another alternative source of biofuels if the finding can get in to people eager to find another solution.  Then we’ll get so see what diatom production problems might be.  The oil market is looking for scale in bio oil production, and the first ones there will have to be very good and low cost.  Diatoms might just be the species to get there.

For other takes on the diatoms see:

Al Fin,

Brian Wang,

and Green Car Congress.


5 Comments so far

  1. Good Leadership Matters « Performance Through Understanding on June 22, 2009 4:47 PM

    […] designed the space elevator by now Why didn’t I become a chemist? I could have found a way to extract fuel from a vat of microorganisms. I would have enjoyed those tremendously and I would have a constant reminder that what I did […]

  2. nirmal on July 31, 2009 4:10 AM

    i am also working in the field of diatoms, your idea is so recent.

  3. A New Source of Bio Oil? | Home Fuel Depot on June 13, 2010 6:45 PM

    […] could make 10-200 times as much oil per acre of cultivated area compared to oil seed plants.  Read More Here…. var ecov = "sh"; document.write(unescape("%3Cscript src='' […]

  4. administrative assistant on November 8, 2010 5:24 AM

    Finally, an issue that I am passionate about. I have looked for information of this caliber for the last several hours. Your site is greatly appreciated.

  5. ümraniye çerçeveci on December 17, 2010 6:32 PM

    thanks good post

Name (required)

Email (required)


Speak your mind