The Microbial Way of Reducing CO2 Emissions in the Air

As of now, CO2 emissions have been a continuous and growing threat to our environment.  The rises in
greenhouse gasses and carbon dioxide have slowly pushed our global climate towards a catastrophic environment, one which will completely manifest in the future if we don't act soon.  Scientists, researchers, and engineers alike have been searching for a new and improved way to eliminate the rise of carbon dioxide within our air.  Now, we may actually have a plausible way to reduce emissions that is efficient, beneficial to the environment, and cost effective.

All it takes is a little help from the microbial world.

The nonphotosynthetic bacterium, Moorella thermoacetica, actually does not use photosynthesis to create energy.  In fact, it utilizes the acetyl-CoA pathway to cycle carbon in the environment.  Normally, the amount of carbon this bacterium cycles is small, leading to a small amount of acetic acid that is produced.  However, researchers Kelsey K. Sakimoto, Andrew Barnabas Wong, and Peidong Yang conducted a recent study to determine if the efficiency and amount of carbon that is cycled by M. thermoacetica could be improved.

The research team used a hybrid approach and combined Moorella thermoacetica and cadmium sulfide nanoparticles to enable an increase in photosynthesis of acetic acid from carbon dioxide.  This reaction is a two step synthesis.  To begin with, "the precipitation of CdS (cadmium sulfide nanoparticles) by Moorella thermoacetica is triggered by the addition of Cd2+ and cysteine as the sulfure source.  Moorella thermoacetica uses photogenerated electrons from illuminated CdS to carry out photosynthesis.  The absorption of a photon by CdS produces an electron and hole pair, e- and h+.  The electron generates a reducing equivalent that is passed on [...] to synthesize acetic acid from Co2."  Essentially, the addition of CdS to Moorella thermoacetica allows the bacterium a greater capacity for the photosynthesis of acetic acid from CO2.  From this, the team concluded that the amount of acetic acid that was synthesized was greater than the amount produced solely by the bacterium.

In order to determine that this process was successful, the team conducted another experiment where different components of the reaction were removed.  For example, the team removed the light source in one round and the CdS in another round.  As a result, the amount of acetic acid that was created in the absence of light slowly declined to 25% of the regular amount after 4 days, while the amount that was created with just Moorella thermoacetica dropped to almost 0% after only one day.  This confirms that Moorella thermoacetica and CdS hybrids exposed to light produce acetic acid from CO2.

Overall, this new discovery could pave the way for reduced carbon emissions in our air.  In addition, this hybrid organism could provide the ability to study biological systems and carbon cycling that may take place.  Granted, this would not be an overnight process, and a large amount of the bacterium would be required.  But it is an excellent first step into a budget friendly and efficient way to reduce carbon dioxide in the atmosphere.

For more information on Moorella thermoacetica, click these links (note the last one is an entire paper on the genome and properties of this bacterium):
https://microbewiki.kenyon.edu/index.php/Moorella_thermoacetica
http://research.uvu.edu/wilson/bacterium.htm
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2575129/

For more information on this study, the link to the research paper is provided here:
http://science.sciencemag.org/content/351/6268/74.full