Scientists have created bacteria covered in tiny semi-conductors that generate a potential source of fuel from sunlight, carbon dioxide and water.
The so-called “cyborg” bugs produce acetic acid, a chemical that can then be transformed into fuel and plastic.
In laboratory experiments, the bacteria proved to be much more efficient at harvesting the sunlight that the plants.
The work was presented to the American Chemical Society meeting in Washington.
The researchers have tried to artificially reproduce photosynthesis for many years.
Solar panel bugs
In nature, the green pigment, chlorophyll is the key to this process, helping plants to convert carbon dioxide and water, using sunlight, into oxygen and glucose.
But despite the fact that it works, scientists say that the process is relatively inefficient. This has also been a big problem with most of the artificial systems developed to this day.
This new approach aims to improve the efficiency, aiming mainly to equip the bacteria with solar panels.
After combing through old microbiology of the literature, researchers have realized that some bugs have a natural defence system to cadmium, mercury or lead, which allows them to turn heavy metal into a sulfide-bacteria is expressed as a small crystal of semi-conductive on their surfaces.
“It is shamefully simple, we have exploited the natural ability of these bacteria which had never been looked at through this lens,” said Dr. Kelsey Sakimoto of the University of Harvard in Massachusetts, united states.
“We grow and we introduce a small amount of cadmium, and, naturally, they produce cadmium sulphide crystals that then clump together on the outer sides of their body.”
“You grow up in their liquid, broth, and you just add small aliquots of cadmium in solution and you wait for a few days, and fate of these photosynthetic organisms.
“It is very simple, mix-in-a-pot-of chemistry.”
These new stimulated the bacteria produce acetic acid, essentially vinegar, CO2, water and light. They have an efficiency of around 80%, i.e. four times the level of solar panels, and more than six times the level of chlorophyll.
“We pricing of these cyborg bacteria and their ability to make the acetate because they produce a substrate that can already use it to produce of the most valuable and the most interesting of products,” said Dr. Sakimoto.
“We have employees who have a number of strands of E. coli that are genetically modified to take the acetic acid as their food source and they can upgrade in the butanol and a polymer called polyhydroxybutyrate.”Soak in the Sun
Dr. Sakimoto is of the opinion that these bacteria offer some advantages compared to other approaches to generate green energy from biological sources.
Other techniques for artificial photosynthesis costly solid electrodes.
The cyborg bug approach really only need large tanks of liquid to be kept outside in the Sun – the bacteria are self-replicating and self-regenerate, which makes it potentially a bit of a waste of the technology. It works better in rural areas or in the developing world.
The research work has been carried out at the University of California, Berkeley, in the laboratory of Dr. Peidong Yang.
“The thrust of research in my laboratory is essentially a “booster” non-photosynthetic bacteria by providing energy in the form of electrons from inorganic semiconductors such as cadmium sulfide, which are efficient light absorbers,” Dr. Yang said.
“We are now looking for more benign of the light absorbers that the cadmium sulfide to provide the bacteria with the energy of the light.”
The researchers believe that, although their approach has taken an important new step, it could not be, in the end, technology wins.
“There are so many different models of these systems to come, and really we have only begun to explore the different ways in which we can combine chemistry and biology,” said Dr. Sakimoto.
“And there is a real possibility that there will be a few upstart technology that will come out that will do better than our system”.
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