HOT HOT HOT !
The summer of 2022 was undoubtedly a very hot and unbearable period. According to media reports, high temperatures and drought have triggered wildfires from Portugal to the Balkans, killing hundreds of people. in the Arctic Circle, the temperature once soared to 32.5 ℃, and the ice sheet covering Greenland, the world's largest island, is also melting faster. About 6 billion tons of ice are lost every day. In China, the entire Yangtze River Basin is short of water, resulting in a sharp drop in the daily power generation of hydropower, causing many places to cut electricity, and affecting the lives and work of many people.
Serious Climate Crisis
According to the sixth assessment report of the Intergovernmental Panel on Climate Change (IPCC), global warming in the past 50 years is occurring at an unprecedented rate since the past 2000 years, and the instability of the climate system is increasing. Friederike Otto, a leading UK climatologist and member of the core writing team of the IPCC's Sixth Assessment Report, said: "Greenhouse gas emissions from the burning of fossil fuels such as coal, gas, and oil are making heatwaves hotter, more persistent and more frequent."
In Urgent Need of an Alternative Plan
Therefore, how to reduce the greenhouse gas emissions caused by the burning of fossil fuels is the top priority of the global warming solution. Fossil fuels are used to provide energy. Nowadays, the total annual energy consumption in the world is about 13.4 billion tons of standard coal, of which fossil energy accounts for 85%, while clean energy only accounts for 15%. These data are a wake-up call for us. Thus, our team has been focusing on alternatives to traditional energy since last year.
MFC Stands Out in a Crowd
Among the new energy sources, hydropower, wind power, solar power, and tidal power are highly limited by environmental conditions. After considering many forms, our eyes turned to microbial fuel cells(MFC). MFC can directly convert chemical energy stored in organic matter into electricity and have important applications in power generation and wastewater treatment.
Our Project: MFC improvement
However, current MFCs generally exhibit undesirably low power density. So how to improve the power density?
With this question, we interviewed an investor in the field of biotechnology, who knows a lot about electrogenic microorganisms. He told us that MFC has three main limiting factors: electrodes, device design, and strains. And for strains, the sluggish transmembrane and extracellular electron-transfer processes are the biggest flaws. After brainstorming, we decided to solve this problem with synthetic biology.
Introducing Shewanella transmembrane and outer-membrane silver nanoparticles can boost the charge-extraction efficiency, reports a study published in 2021 in Science. They added chemically synthesized AgNPs to electrodes and their MFC reached the highest current density ever. This research aroused our interest in AgNPs. We plan to display a silver-binding protein on the membrane of Shewanella to help it capture silver ions and reduce silver into nanoparticles so as to boost charge-extraction efficiency in Shewanella microbial fuel cells.
