First step in producing silicon-based life

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The Horta live! Scientists have succeeded in creating a bacteria that can produce hydrocarbon compounds that incorporate silicon into their make-up.

To get biology to adopt silicon, Frances Arnold, a chemist at the California Institute of Technology (Caltech) in Pasadena, along with postdoctoral assistant Jennifer Kan and graduate student Rusty Lewis, started by isolating a so-called thermophilic bacterium, which grows in hot springs. Like many organisms, the bacterium contains an enzyme called cytochrome c, which shuttles electrons to other proteins, making it widely useful in biochemistry. In some cases, however, enzymes in thermophilic bacteria expand their roles to carry out other reactions on the side. So the Caltech researchers tested their microbe and found that in rare cases its cytochrome c also added silicon to hydrocarbons.

In nature, Arnold notes, cytochrome c’s silicon-adding ability is so feeble that it’s probably just a byproduct of the enzyme’s function—not even close to its primary role. To try to beef it up, the team incubated the bacteria with silicon and carbon compounds and selected the organisms that produced the most hydrocarbons that incorporated silicon. After only three rounds of this artificial selection, the enzymes had evolved to churn out silicon-containing hydrocarbons 2000 times as readily as natural cytochrome c. “The power of evolution really shows up when a new function appears and then is forced to adapt via directed evolution,” Arnold says.

For now, the silicon-spiked hydrocarbon compounds, called organosilanes, probably aren’t useful either to the bacteria or to industry. They’re short and stubby, unlike the long chainlike versions that chemical companies make for uses such as adhesives, caulks, and sealants.

As the article notes, they really are very far from creating a silicon-based life. Still, to get silicon incorporated into carbon-based organic chemistry is a significant first step, as it demonstrates that the theory of silicon-based life might very well have merit.


  • Ted

    “I’m a doctor Jim, not a brick layer.” Bones to Kirk.

  • Wayne



  • Daniel J Hoover, PhD

    Diatoms (a type of algae) utilize silicon as well. They use an oxidized form: silicon dioxide (silica) in their cell wall (and what a cell wall! Such beauty, such symmetry). They permeate the upper layers of the oceans in vast numbers and when they die, their ‘skeletons’ accumulate and form deposits of diatomaceous earth (DE) that we calcium boned creatures use in our pool filters.
    PS, DE was also used as a ‘sponge’ to hold liquid nitroglycerine in order to form sticks of dynamite.
    But I digress; Diatoms are creatures that utilize silicon.

  • Phill O

    The use by diatoms is well documented. However, the fact that silicon is essential to our lifeforms has long gone forgotten.

    The original discovery used chickens on silicate enriched and depleted diets. The chicks on the silicate depleted diets showed significant connective tissue malformation and poor growth; kind of like the difference between Dolly Parton and Twiggy.

    Oltmann used the lens from Small mouth Bass to test a hydrogen peroxide decomposition followed by derivative neutron activation analysis determination of silicon in biological tissue. I am not aware of any followup for silicon determinations in tissues. However, this should be done!

  • D K Rögnvald Williams

    Someday humans may be supplanted by a more evolved species, homo supersillius.

  • Phill O

    “homo supersillius” This might relate to one of the democratic candidates!

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