Scientists teach bacterium a new trick for artificial photosynthesis

January 4, 2016 by Lynn Yarris
The bacterium Moorella thermoacetica is being used to perform photosynthesis in a hybrid artificial photosynthesis system for converting sunlight into valuable chemical products.

Trainers of dogs, horses, and other animal performers take note: a bacterium named Moorella thermoacetica has been induced to perform only a single trick, but it's a doozy. Berkeley Lab researchers are using M. thermoacetica to perform photosynthesis – despite being non-photosynthetic – and also to synthesize semiconductor nanoparticles in a hybrid artificial photosynthesis system for converting sunlight into valuable chemical products.

"We've demonstrated the first self-photosensitization of a non-photosynthetic bacterium, M. thermoacetica, with nanoparticles to produce from at efficiencies and yield that are comparable to or may even exceed the capabilities of natural ," says Peidong Yang, a chemist with Berkeley Lab's Materials Sciences Division, who led this work.

"The bacteria/inorganic-semiconductor hybrid artificial photosynthesis system we've created is self-replicating through the bio-precipitation of cadmium sulfide nanoparticles, which serve as the light harvester to sustain cellular metabolism," Yang says. "Demonstrating this cyborgian ability to self-augment the functionality of biological systems through inorganic chemistry opens up the integration of biotic and abiotic components for the next generation of advanced solar-to-chemical conversion technologies."

Yang, who also holds appointments with UC Berkeley and the Kavli Energy NanoScience Institute (Kavli-ENSI) at Berkeley, is the corresponding author of a paper describing this research in Science. The paper is titled "Self-photosensitization of non-photosynthetic bacteria for solar-to-chemical production." Co-authors are Kelsey Sakimoto and Andrew Barnabas Wong.

How to train your bacterium
Nanoscience expert Peidong Yang holds appointments with Berkeley Lab, UC Berkeley and the Kavli Energy NanoSciences Institute at Berkeley. Credit: Roy Kaltschmidt

Photosynthesis is the process by which nature harvests sunlight and uses the solar energy to synthesize carbohydrates from carbon dioxide and water. Artificial versions of photosynthesis are being explored for the clean, green and sustainable production of chemical products now made from petroleum, primarily fuels and plastics. Yang and his research group have been at the forefront of developing artificial photosynthetic technologies that can realize the full potential of solar-to-chemical synthesis.

"In our latest study, we combined the highly efficient light harvesting of an inorganic semiconductor with the high specificity, low cost, and self-replication and self-repair of a biocatalyst," Yang says. "By inducing the self-photosensitization of M. thermoacetica with cadmium sulfide nanoparticles, we enabled the photosynthesis of acetic acid from carbon dioxide over several days of light-dark cycles at relatively high quantum yields, demonstrating a self-replicating route toward solar-to-chemical carbon dioxide reduction."

Cadmium sulfide is a well-studied semiconductor with a band structure and that is well-suited for photosynthesis. As both an "electrograph" (meaning it can undergo direct electron transfers from an electrode), and an "acetogen" (meaning it can direct nearly 90-percent of its photosynthetic products towards acetic acid), M. thermoacetica serves as the ideal model organism for demonstrating the capabilities of this hybrid system.

"Our hybrid system combines the best of both worlds: the light-harvesting capabilities of semiconductors with the catalytic power of biology," Yang says. "In this study, we've demonstrated not only that biomaterials can be of sufficient quality to carry out useful photochemistry, but that in some ways they may be even more advantageous in biological applications."

Explore further: Another milestone in hybrid artificial photosynthesis

More information: K. K. Sakimoto et al. Self-photosensitization of nonphotosynthetic bacteria for solar-to-chemical production, Science (2015). DOI: 10.1126/science.aad3317

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1 / 5 (1) Jan 04, 2016
It is Really Great. Science is Galloping.
Does it serve a Sandwich on the Table too? Let it Contact Amazon to Deliver by Drones.
3 / 5 (2) Jan 04, 2016
I am not often prone towards Franekstein scenarios but because photosynthesis potentially enables self-sufficiency, providing such capabilities to new species should be handled with extreme care.
1.7 / 5 (6) Jan 04, 2016
This can be another way to make petroleum just a nasty stinky substance again.

BTW, the phrase should read "It's a Deusy", in reference to the Deusenberg.
3.7 / 5 (6) Jan 04, 2016
This can be another way to make petroleum just a nasty stinky substance again.

BTW, the phrase should read "It's a Deusy"
Uh no, anal-retentive retard. Nobody spells it that way.
1.7 / 5 (6) Jan 04, 2016
"Uh no, anal-retentive retard"

So, . . that's why you were looking so closely at my bottom. Find what you wanted?
3 / 5 (4) Jan 04, 2016
"Uh no, anal-retentive retard"

So, . . that's why you were looking so closely at my bottom. Find what you wanted?
You do realize georgie that if this were a company you would have been fired by now.

Just like all those other positions you lost because, well, youre a psychopath arent you? At least thats the way it appears. And not a very talented one it seems.

How many was it - a dozen or so? And just WHY is it that you are you so eager to brag about all the jobs you lost???
3 / 5 (4) Jan 04, 2016
WHY are you so eager to expose your failures george? You claim that you held many many wonderous positions but its obvious to everyone that you couldnt hold on to any one of them.

The only conclusions we can reach are that 1) you were unqualified to hold them and incompetent when trying to do them, and 2) you lied about your education and experience in order to get them.

Just like you do here.

Whats the saying? 'Insanity is doing the same thing over and over and expecting different results'.

Youre a failure here as well because you do the same things here that got you fired out there.

"The psychopath does not think that they have any psychological or emotional problems, and they see no reason to change their behavior to conform to standards with which they do not agree. They are well-satisfied with themselves and their inner landscape."
1.8 / 5 (5) Jan 04, 2016
Mirror talk?
5 / 5 (1) Jan 10, 2016
The origin of the American slang word "doozy" or "doozie", meaning something excellent or powerful, is unknown. Merriam-Webster completely rejects any origin in the automobile, noting doozy originally appeared as "dozy" in eastern Ohio in 1916 — four years prior to the production of the first Duesenberg vehicles. They also claim there is little evidence connecting the Duesenberg and doozy during the 1920s and 1930s, when the car was most popular. "Dozy" is akin to the verb "dozen" that is semantically and etymologically related to "daze" and that is attested in slang terms such as "the dozens."[wikipedia on deusenberg]

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