Potential-driven balance of extracellular electron transfer activity and Microstructure stability in Shewanella biofilm for uranium recovery.

Authors

Hong Shu, Qian Li, Wenjiao Hu, Qing Xu, Guangyue Li, Honghao Li, Jing Sun

Published in

Bioresource technology. Pages 135867. Sep 19, 2026. Epub Sep 19, 2026.

Abstract

Bioelectrochemistry enables uranium recovery from uranium-contaminated water. Within microbial electrolysis cells (MECs), electroactive biofilm growth is critical, but the impact of electrode potential on biofilm structure and function remains unknown. This study explored variations in micro-structure, extracellular electron transfer, and uranium recovery of Shewanella oneidensis MR-1 biofilms cultivated under different potential shocks from -0.2 to 0.6 V (vs Ag/AgCl) in MECs at -0.2 V. Across this range, uranium recovery exhibited a clear non-monotonic trend, peaking at 0.2 V and exhibiting the most unreliable performance at 0.6 V. At 0.2 V (low potential, LP), the biofilm electrode exhibited 99.72 % uranium recovery with 42.19 % U(IV) reduction. Additionally, transmission electron microscopy revealed needle-like mineral within the inner extracellular polymeric substances (EPS), attributed to moderate c‑type cytochrome (c-Cyts) density (104.89 % of open circuit potential, OCP), suitable charge transfer resistance (R_ct, 68.34 % of OCP), and a dense EPS network (bulk density 138.07 % of OCP). At 0.6 V, the biofilm exhibited higher electrochemical activity (c-Cyts 113.15 % and R_ct 48.41 % of OCP), but poorer structural stability (EPS bulk density 101.38 % of OCP), causing fluctuating recovery (99.39 % to 94.10 %) and a lower U(IV) proportion (33.90 %). These results indicate that balancing biofilm activity and structural stability is essential for efficient and sustainable recovery of uranium. The LP biofilm electrode achieved 98.09 % uranium recovery with a surface distribution coefficient (K_d,s) of 1.414 L/cm² in real mining groundwater. This finding presents a balance model linking biofilm electrode activity and stability, highlighting the necessity of regulating cultivation potential shock.

PMID:
42762932
Bibliographic data and abstract were imported from PubMed on 20 Sep 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.