HAMILTON, New York — It seems like a project of alchemy; bacteria that are capable of generating energy from ordinary substances sounds a lot like turning dirt into gold. Despite this fact, researchers have discovered that not only is this feat possible, it may pave the path for a promising future in the global reduction of energy poverty.
In several major experimental breakthroughs in the growing research experiments on artificial photosynthesis, scientists have discovered that different types of bacteria can convert solar energy into electricity. Two such projects have been fundamental to this field of research. In one, researchers at the University of Berkeley have found that an unnamed bacteria produces energy by naturally growing “mini solar panels” in response to certain heavy metals. The resulting organism is extremely efficient (80%) in energy production, surpassing both commercial energy panels and plant photosynthesis. In the other, E. The researchers engineered Coli, a common bacteria, to become a powerful convertor of organic matter into electricity. Its ability to convert a wide variety of unwanted substances, such as wastewater, into a viable energy source, makes it a revolutionary discovery in the field of renewable energy.
If utilized on an industrial scale, these findings could have the ability to provide energy to more than 1.2 billion people suffering from the impacts of energy poverty, according to Global Citizen. The future possibilities of these projects look promising, but is it truly a viable goal to attempt their spread to an industrial scale? These are difficult questions. The Borgen Project spoke with Dr. Geoffrey Holm, Chair of the Biology Department at Colgate University, to gain some valuable insight on the matter.
Solar Panel Bacteria at Berkeley
Conducting a thorough search of past bacteria projects, a research team at Berkeley discovered that a type of bacteria has a compelling ability to create natural defenses that absorb sunlight to generate electricity. The researchers generated these tiny crystal semiconductors as a response to certain heavy metals. They found that the bacteria can easily be grown in a liquid broth and afterward exposed to cadmium. Within a few days, the bacteria was able to convert sunlight into energy at an extremely high efficiency, Global Citizen reports.
Dr. Holm provided some insight into the intricate process that occurs within this mechanism: “Essentially I think what is happening is that the bacteria respond to the heavy metals by extruding them onto the surface as crystals of cadmium sulfide. These crystals are photoreactive, which means that electrons are boosted to a higher energy state by the energy from a photon, similar to what happens in chlorophyll. Those high energy electrons can find application in metabolic processes such as the conversion of CO2 into acetate.”
The cadmium sulfide crystals that this organism extruded showed an 80% efficiency in energy conversion; this quadruples that of commercial solar power and surpasses even plant photosynthesis. With enough development, this experiment has the potential to bring working electricity to 1.2 billion people who live in energy poverty. The simplicity and accessibility of the process make it especially applicable in impoverished rural areas.
Electricity-Producing E. Coli
Since then, there have been more experiments to expand research on energy-converting bacteria. Professor Ardemis Boghossian led a group of researchers that discovered that E. Coli can generate power in a variety of settings. Its wide accessibility as a common microbe encompassing a wide range of bacteria, combined with its ability to generate energy from wastewater makes it remarkably efficient as a viable future dual-purpose solution for both energy poverty and waste reduction.
The process by which E. Coli produces energy is termed extracellular electron transfer (EET). This process occurs in microbial fuel cells, which use an electrode to extract the electricity from the bacteria. To produce the maximum energy output, the team took a creative approach. Instead of engineering the electrodes to produce maximum electricity output, the researchers focused on engineering the bacteria instead. The team engineered bacteria to exhibit enhanced EET, making them function as highly efficient electric microbes without the need for catalysts, or substances that need to be added to increase the rate of a reaction.
They also engineered the bacteria for maximum energy output by introducing components from Shewanella oneidensis MR-1 into the E. Coli. This generated a complete EET pathway and allowed the E. Coli to transfer electrons from inside the cell into the outside environment to produce a copious output of electricity. The engineered bacteria showed a “three-fold increase in electrical current generation compared to conventional strategies,” according to ANI News.
Eliminating the Need for Energy Input
Unlike regular E. Coli, the engineered energy-producing bacteria do not need any specific chemicals for energy generation, according to ANI News. As well as its use in the applications of energy production, this new energy-producing bacteria can also be an alternative source for wastewater treatment, as it showed a remarkable ability to perform in a variety of different environments, such as in wastewater collected from a brewery.
The bacteria’s ability to function in environments where exotic electric microbes falter shows a possible future expansion of this project for widespread wastewater treatment and energy production. It shows promise of becoming an alternative source of wastewater treatment, potentially reducing the environmental impact of traditional wastewater treatment plants, which consume a large amount of energy and produce about 3% of greenhouse gas emissions, Anthropocene Magazine reports. The fuel cells in use at these plants are inefficient and can only produce energy from a limited range of sources.
The bacteria’s application to bioelectronics is limitless and can have various applications such as microbial fuel cells, electrosynthesis and biosensing, truly proving itself to be a versatile tool for sustainable energy development.
Since then, scientists have been developing other forms of artificial photosynthesis. Dr. Holm provided examples of other energy-producing bacteria projects that are aimed at reducing energy poverty as well: “Angela Belcher at MIT (one of my former students worked in her lab for a summer) leads one project I know of. She is using bacteriophage to make ‘nanowires’ that can be used in superconductors, high capacity batteries and solar cells – all with an eventual aim of reducing the costs and access to electricity, especially in rural communities.”
It is possible that the novel research on energy-producing bacteria will accelerate the solar revolution in the future. Dr. Holm provides a realistic take on the future prospects of these projects, but he still holds faith in their implications in the more distant future: “These projects have a ways to go before they can be scaled up and make a large impact. There is a huge difference between getting something to work in a test tube in controlled laboratory conditions and getting it to work ‘in the field’ on a large scale enough to make a difference.”
Dr. Holm also explained that “There is still lots of downstream processing that needs to happen to turn [these projects]into something that would be able to be viable to address the needs of impoverished communities. Research groups are working on that, too, I am sure, but it all has to come together in a way that will meet the needs of these communities while still being at a price point that is viable.”
There is still a copious amount of work necessary, but it seems that energy-producing bacteria have a promising future in poverty reduction.
– Sophia Holub