A team led by UCLA scientists and engineers has made an important step in the creation of microbial fuel cell which is a method that makes use of naturally occurring bacteria to take electrons out of organic material found in the water to create electrical currents. The study that outlines the breakthrough has been published by Science.
“Living energy-recovery systems utilizing bacteria found in wastewater offer a one-two punch for environmental sustainability efforts,” said co-author Yu Huang, a professor, and chair of the Materials Science and Engineering Department at the UCLA Samueli School of Engineering. “The naturally occurring bacteria can aid in decontaminating groundwater by dissolving toxic chemical substances. The research we conducted provides a feasible method to make use of renewable energy generated by the process.”
The research team concentrated on the genus of bacteria Shewanella that are extensively studied for their energy-generating capabilities. They can thrive in any environment which includes the sea, soil, and wastewater regardless of the oxygen levels.
Shewanella species naturally reduce organic waste in smaller molecules and electrons are an end product of the process. If the bacteria form films on electrodes of the electrons may be stored, forming a microbial fuel cell that generates electricity.
However, the microbial fuel cells that are powered by Shewanella oneidensis have not attained enough currents from bacteria to allow the technology to be used to use in industrial settings. The electrons aren’t moving fast enough to pass through the membranes of the bacteria and reach the electrodes, thereby supplying sufficient electricity and currents.
To resolve this issue the researchers added nanoparticles made of silver to electrodes comprised of a kind made of graphene oxide. Nanoparticles release silver ionsthat bacteria convert to silver nanoparticles by using electrons generated by their metabolic processes and integrate into their cell. When they are inside the bacteria they act as tiny transmission wires taking in more electrons generated by bacteria.
“Adding the silver nanoparticles into the bacteria is like creating a dedicated express lane for electrons, which enabled us to extract more electrons and at faster speeds,” said Xiangfeng Duan, the study’s co-author and professor of biochemistry and chemistry at UCLA.
With an increase in energy transfer efficiency for electrons, the silver-infused Shewanella film can deliver over 80% of electrons that are used for metabolic processes to the external circuits and generates an energy output that is 0.66 milliwatts for every square centimeter, which is more than double that of the prior best of fuel cells based on microbial sources.
With the increase in power and efficiency this investigation, funded through the Office of Naval Research, revealed that fuel cells powered by the silver-Shewanella hybrid bacteria could allow to provide sufficient power in the real world.
Referred to as “Silver nanoparticles boost charge-extraction efficiency in Shewanella microbial fuel cells” by Bocheng Cao, Zipeng Zhao, Lele Peng, Hui-Ying Shiu Mengning Ding Frank Song, Xun Guan Calvin K. Lee, Jin Huang, Dan Zhu, Xiaoyang Fu, Gerard C. L. Wong, Chong Liu, Kenneth Nealson, Paul S. Weiss, Xiangfeng Duan and Yu Huang, 17 September 2021, Science.
Bocheng Cao, a UCLA doctoral student whose advisors include Huang and Duan Huang, is the primary author of the study. The other UCLA senior authors include Gerard Wong, a professor of bioengineering; Paul Weiss, a UC President’s Chair and a distinguished professor of biochemistry and chemistry as well as bioengineering and engineering and materials science as well as Chong Liu as the assistant professor in biochemistry and chemistry. Kenneth Nealson, a professor of earth sciences emeritus at span data-cmtooltipis” USCFounded at the end of 1880 in 1880, the University of Southern California is among the top privately-owned research institutions. It is situated in the center in Los Angeles.” USC She and is also an experienced writer.
Duan, Huang and Weiss are all part of the California NanoSystems Institute at UCLA.