Microorganisms Producing Elemental Carbon

By Umar Mohammad

January 7, 2022

UPDATED 12:00 PM EST

[Photo : MARUM – Center for Marine Environmental Sciences, University of Bremen]

Let’s start by breaking down this mismatch of terms for your own sake, as the fellow reader...

What are microorganisms?

Microorganisms are defined as organisms on a microscopic level (as the name indicates). They

include Viruses, Bacteria, Archaea, Fungi, and Protists to name the main ones.

What is elemental carbon?

Elemental carbon exists in two crystalline allotropic forms that you all should know from your

chemistry classes - graphite, and diamond. It also exists as the fullerene structure and turbostratic crystalline forms. Carbon can take up many different forms due to its four valence electrons. The production of this form of carbon usually requires high pressure and temperature, when there is no biological involvement (e.g. enzymes). The formation of fossil fuels expels pure carbon (in a crystalline format). Now to put the jargon aside, the form of elemental carbon produced from microorganisms is amorphous carbon. Soot is a form of amorphous carbon; the common product after the combustion of wood, oil, or gas.

Archaea are a single-celled prokaryote (type of microorganism) that undergoes anaerobic respiration, whereby oxygen is not needed for its survival. These organisms reproduce asexually

via binary fission but take a long time, relative to other microbes. During cultivation, researchers

realized that the organisms became a dark color; they immediately deduced the powder to consist of a metal sulfide.

Dr. Wegner from Bremen University cultivated symbiotic archaea, and his confrères (a fancy

word for colleagues) extracted methane-oxidizing cultures from the said cultivated archaea. Organic solvents were used, as they are better than water when extracting neutral compounds. The black substance that remained was almost pure amorphous carbon. To confirm that these microbes were the sole producers of this pure carbon, they broke down the substance derived

with isotopically labeled carbon and analyzed the final product of carbon. This discovery is still relatively new; it was published in October 2021. Countless questions are still unanswered, the quintessential one being - how was it formed?

What is known is that amorphous carbon is an extremely good conductor of electricity, although the amount of this form of carbon produced by said microorganisms is still unknown. With the recent discovery, scientists can delve deeper into this branch of microbiology and hopefully develop newer ideas.

References

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Accessed 16 Dec. 2021.

[2] More, Robert B., et al. “Pyrolytic Carbon for Long-Term Medical Implants.” Biomaterials

Science, 2013, pp. 209–222, www.sciencedirect.com/topics/engineering/elemental-carbon ,

10.1016/b978-0-08-087780-8.00023-1, Accessed 16 Dec. 2021.

[3] “Microorganisms Produce Elemental Carbon.” Www.mpg.de, 2021,

www.mpg.de/17758388/microorganisms-produce-elemental-carbon. Accessed 16 Dec. 2021.

[4] “Encyclopedia of Life.” Eol.org, 2011, https://eol.org/docs/discover/archaea Accessed 16 Dec.

2021.