Carbon dioxide is one of the significant greenhouse gases. The emission of carbon dioxide from automobiles, industry is posing a great threat to the climate of the Earth. The temperature is rising which leads to melting of ice caps and increase in sea level, it will also lead to extinction of animals that are not able to adapt to high temperature climate.
Cutting down emissions of carbon dioxide and other greenhouse gasses has become an important agenda to many countries.
The recent breakthrough in artificial photosynthesis is a significant one.
The artificial photosynthesis have been achieved by developing a hybrid system of semiconducting nanowires and bacteria that can trap carbon dioxide emissions before it is released in the atmosphere, and then it will convert carbon dioxide into chemical compounds including pharmaceutical drugs, liquid fuels, biodegradable plastic, the system is powered by solar energy.
The natural photosynthesis process is performed by plants, where the plant takes energy from sunlight, takes water and carbon dioxide to synthesize into carbohydrates.
The hybrid system mimics the natural photosynthesis process, but it synthesizes carbon dioxide and water into acetate, which is the common building block for biosynthesis.
The combination of the biocompatible light capturing nanowire arrays with selected bacterial population, the artificial photosynthesis is a great effort to protect environment, solar powered green chemistry using sequestered carbon dioxide.
The hybrid system is an artificial forest of nanowires heterostructured, the naowires are made of silicon and titanium oxide.
When the titanium oxide and silicon nanowires absorb sunlight, photo excited electron pairs are generated; these electron pairs absorb different regions of solar spectrum.
The photo generated electrons from silicon will be passed into bacteria for co2 reduction and the photo generated holes in titanium oxide split water molecules to make oxygen.
The forest of nanowires is arranged then it is populated with microbial populations that produce enzyme which selectively catalyze reduction of carbon dioxide.
The bacteria used are sporomusa ovate, an anaerobic bacterium that accepts electrons from the surroundings and uses them to reduce carbon dioxide.
The carbon dioxide is reduced by S. ovate to acetate, and then genetically engineered E. coli are used to synthesize targeted chemical compounds.
For the study and to improve the yields of chemical compounds, the two bacteria are kept separate.
In the future they may be combined in one step.