Artificial Photosynthesis is going to start a new era in human history. Scientists at University of California Berkeley are working on creating the phenomenon of photosynthesis artificially. As of now, the research team has created a bioreactor consisting of bacteria loaded with Cadmium Sulphide semiconductor nanocrystals. This setup converts the light, water and sunlight into useful chemicals, which are expected to be the chemicals that appear during photosynthesis.
Kelsey K Sakimoto of Peidong Yang, Berkely has been working on cyborg bacteria. In the National Meeting and Exposition of the American Chemical Society, he has demonstrated the bacterial called Moorella Thermoacetica, that is capable of self-assembling into nanocrystals cyborgs. These cyborgs can super charge the bacteria present in the reactor into CO2-reduction powerhouses.
The nanocrystal-clad bacteria are able to achieve a high breakdown efficiency of up to 84 percent, overcoming the issue of a CO2 reduction in which a soup of byproducts results from the process. While this approach doesn’t lead to a synthetic fuel, like ethanol, it does produce just one product: acetic acid.
While acetic acid isn't terribly useful on its own, other bacteria love it. We have strains of engineered E. coli that are engineered to eat the acetic acid and produce butanol, the bioplastic polyhydroxybutyrate, and a family of pharmaceutical compounds. We think acetic acid is an ideal intermediate product as most engineered strains of bacteria can use it to really make any product under the sun.
Kelsey K Sakimoto of Peidong Yang, Berkely has been working on cyborg bacteria. In the National Meeting and Exposition of the American Chemical Society, he has demonstrated the bacterial called Moorella Thermoacetica, that is capable of self-assembling into nanocrystals cyborgs. These cyborgs can super charge the bacteria present in the reactor into CO2-reduction powerhouses.
It's actually a natural, overlooked feature of their biology. This bacterium has a detoxification pathway, meaning if it encounters a toxic metal, like cadmium, it will try to precipitate it out, thereby detoxifying it. So when we introduce cadmium ions into the growth medium in which M. thermoacetica is hanging out, it will convert the amino acid cysteine into sulfide, which precipitates out cadmium as cadmium sulfide. The crystals then assemble and stick onto the bacterium through normal electrostatic interactions. - Sakimoto.
Principle of semiconductors for CO2 reduction:
Semiconductor materials have a bandgap, and when photons with energy levels greater than that of the bandgap, electron-hole pairs are generated. Once can assume bandgap as the threshold energy of a material either to act as a conductor or an insulator. This is the principle through which semiconductor materials are used for converting solar energy into electrical energy. This principle is the base of reducing CO2 reduction through artificial photosynthesis.Functioning of the reactor:
The enzymes in the bacteria's membrane associate and attach themselves to the nanocrystal. When the cadmium sulfide is excited with light, the excited electron from the conduction band is injected into the enzyme, which produces some sort of biological electron carrier (like H2) that is used for the CO2 fixation pathway. The position of the conduction band is crucial as it must be high enough to pass into the enzyme, which is expected to be hydrogenase.The nanocrystal-clad bacteria are able to achieve a high breakdown efficiency of up to 84 percent, overcoming the issue of a CO2 reduction in which a soup of byproducts results from the process. While this approach doesn’t lead to a synthetic fuel, like ethanol, it does produce just one product: acetic acid.
While acetic acid isn't terribly useful on its own, other bacteria love it. We have strains of engineered E. coli that are engineered to eat the acetic acid and produce butanol, the bioplastic polyhydroxybutyrate, and a family of pharmaceutical compounds. We think acetic acid is an ideal intermediate product as most engineered strains of bacteria can use it to really make any product under the sun.
0 comments:
Post a Comment