A research team has unveiled a groundbreaking method for environmental cleanup by utilizing iron mineral-bacillus megaterium biofilms, which act as “biocapacitors.” This innovative approach involves storing solar energy and releasing it in dark environments to degrade harmful pollutants. The study was published on September 15, 2025, in the journal Environmental and Biogeochemical Processes by researchers from Kunming University of Science and Technology and the University of Massachusetts.
The findings indicate that this biocapacitor mechanism significantly enhances the degradation of antibiotics such as tetracycline hydrochloride and chloramphenicol, marking a significant advancement in bioremediation and sustainable pollution management. Traditionally, solar radiation”s role was primarily associated with plant photosynthesis; however, recent research highlights the ability of non-phototrophic microorganisms in soils and sediments to harness solar energy through interactions with minerals.
This emerging area of biophotoelectrochemistry suggests that sunlight can influence microbial metabolism and geochemical processes, even in environments with limited light penetration, such as soils and sediments. The study specifically examined the interactions between iron minerals, including Fe2O3 and FeOOH, and the bacterium Bacillus megaterium, focusing on the accumulation and release of electrons during light-dark cycles.
The co-culturing system demonstrated a continuous charge-discharge function and a noteworthy photovoltage memory effect. As the density of the bacterial biofilm increased, the electron storage capacity, indicated by the total accumulated charge, also rose. The results displayed a distinct difference in charge accumulation during light exposure compared to the release in darkness, with systems exposed to light consistently achieving higher charge values. The net accumulated charge increased notably after several cycles, showcasing the biofilm”s unique photovoltaic memory feature.
Furthermore, the study revealed a significant improvement in the degradation efficiency of the targeted pollutants during the dark phase after exposure to light. Specifically, after just 60 minutes of light exposure, the degradation efficiency for tetracycline hydrochloride and chloramphenicol increased by 66.7% and 46.7%, respectively. This enhancement is attributed to the synergistic interactions between the iron minerals and the bacteria, which facilitated effective electron transfer and storage, allowing the system to function as a biological capacitor.
Structural and electrochemical analyses confirmed that the bacteria-mineral biofilms significantly improved electron transfer and charge storage, leading to enhanced pollutant degradation. These findings underscore the potential of the Fe2O3/Bacillus megaterium biofilm system as a sustainable solution for addressing environmental pollution, particularly in soil and groundwater.
This innovative approach offers a novel method for pollution control that does not rely on continuous illumination, which could transform traditional bioremediation practices. The capability of these biofilms to store and release energy for pollutant degradation in dark environments presents a cost-effective and energy-efficient solution for cleaning antibiotic-contaminated sites.
The research received support from the National Natural Science Foundation of China and various other funding sources, highlighting the significance of this study in advancing environmental science and technology.
For more details, refer to the original publication: Environmental and Biogeochemical Processes.
