Researchers in India have developed microbial fuel cells that remove antibiotic contamination from wastewater while producing electricity and hydrogen peroxide. The laboratory prototype offers a potential approach to wastewater treatment, although its power output remains low.
Microbial fuel cells turn wastewater into a source of energy and valuable chemicals
Wastewater is more than just waste. When properly treated, it can become a source of valuable by-products, as demonstrated by new research from India’s Council of Scientific and Industrial Research-Advanced Materials and Processes Research Institute (CSIR-AMPRI).
A team of researchers have developed a prototype microbial fuel cell capable of removing antibiotics from contaminated water while generating clean electricity and hydrogen peroxide.
The researchers caution that electricity production remains extremely low. However, the significance of the innovation goes beyond the amount of power generated.
Antibiotic resistance is a growing global health threat
One of the challenges this new fuel cell technology could help address is antibiotic resistance, an increasing threat to public health worldwide, including across Africa.
According to data from the European Antimicrobial Resistance Surveillance Network, antibiotic resistance is rising rapidly across European Union countries. Between 2020 and 2024, several types of bloodstream infections caused by resistant bacteria increased.
In 2024, more than 11 cases of bloodstream infections caused by Escherichia coli resistant to third-generation cephalosporins were recorded per 100,000 people, representing a 5.9% increase compared with 2019 levels.
A major driver of this worsening trend is the inappropriate use and overuse of antibiotics in both human and veterinary medicine. However, managing the problem remains the central challenge.
In this context, wastewater is one of the main pathways through which antibiotic-resistant bacteria spread and multiply. Wastewater systems can act as biological incubators where microorganisms develop resistance to medicines.
Improving wastewater treatment is therefore essential.
There is, however, an important distinction. The Indian study focused on an older antibiotic, chloramphenicol, which is now used only in certain developing countries. Interest in the drug has recently increased again because of rising resistance to first-line antimicrobial treatments.
How new electrodes improve microbial fuel cells
The CSIR-AMPRI study builds on a technology that has been known in the energy sector for decades: microbial fuel cells, which generate electricity by capturing electrons released during biochemical reactions catalysed by bacteria.
The technology dates back to the 1930s. However, low power density, high costs and technical limitations have prevented microbial fuel cells from reaching the mass market.
Despite these challenges, several demonstration projects have used the technology to recover energy from wastewater treatment and, in some cases, reduce pathogens.
So what makes this latest development different?
The innovation developed by Yashmeen Budania, Ankita Chaurasiya, Pradip Kumar and Shiv Singh lies in the electrodes.
The researchers created a new type of binder-free electrode using materials that are less expensive than conventional alternatives.
The electrode consists of iron and nickel oxides grown on carbon nanofibres, supported by activated carbon fibre. Bacteria attach to this structure and form a thick biofilm.
This three-dimensional architecture offers several advantages, including low cost, a large surface area and chemical stability.
“Each nanofiber is a tiny wire with a catalyst-containing tip,” Shiv Singh explains.
“This is a laboratory prototype, not a treatment plant. The power is low, but a single electrode capable of performing three functions is a useful starting point.“
Using a neutral electrolyte, the system does more than treat antibiotic-contaminated water and generate electricity.
It also produces hydrogen peroxide (H2O2), a useful oxidising agent widely employed in industry, without requiring an additional external power source.
Study results: 99.99% antibiotic removal and electricity generation
Laboratory tests showed that a dense biofilm at the anode enabled the system to remove 99.99% of chloramphenicol and reduce chemical oxygen demand (COD) by 94% through microbial oxidation.
At the cathode, the system produced hydrogen peroxide, reaching an accumulated concentration of 0.74 mM.
The prototype also achieved the following electrical performance:
- Current density: 153.4 mA/m²
- Power density: 24.68 mW/m²
- Open-circuit voltage: above 0.6 V
Despite these results, the researchers stress that important limitations remain.
“We want to be clear about the limitations. The power output is low, as is generally the case with microbial fuel cells. The antibiotic was transformed, not eliminated. Total organic carbon decreased by about half, and mass spectrometry detected eight degradation products, many of which contained no chlorine atoms. We do not yet know how harmless these fragments are.”
Nevertheless, this is the first time researchers have achieved this combination of three functions within a single microbial fuel cell.
“In the future, we believe we can extend the operating life, test other drugs, assess the toxicity of degradation products and connect several cells in series to increase power output.”
