Radionuclide Reduction by Combinatorial Optimization of Microbial Extracellular Electron Transfer with a...

Area of Science:

• Microbiology
• Environmental Science
• Bioengineering

Background:

• Microbial extracellular electron transfer (EET) is crucial for geochemical cycling, bioenergy, and bioremediation.
• Low EET rates limit applications, particularly in remediating U(VI)-contaminated environments.
• Optimizing resource allocation and coordinating EET pathways remain key challenges.

Purpose of the Study:

• To develop a novel combinatorial optimization strategy for enhancing microbial EET.
• To establish a physiologically adapted, dynamic regulatory platform for Shewanella oneidensis.
• To improve EET performance for bioenergy and environmental remediation applications.

Main Methods:

• Exploration of physiologically adapted regulatory elements to create a dynamic regulatory platform.
• Modular reconfiguration and combinatorial assembly of direct and mediated EET pathways.
• Testing engineered strains in microbial electrolysis cells (MECs) and microbial fuel cells (MFCs).

Main Results:

• Established a regulatory platform with a 271.97-fold strength range for Shewanella oneidensis.
• Achieved significant improvements in MEC current density (up to 16.12-fold) and MFC voltage/power density (up to 4.51- and 8.40-fold, respectively).
• Demonstrated up to 6.53-fold improvement in U(VI) removal efficiency with optimal strains.

Conclusions:

• The developed combinatorial optimization strategy and regulatory platform effectively boost microbial EET performance.
• This approach offers a feasible method for enhancing bioenergy harvesting and bioremediation, including U(VI) removal.
• The engineered strains show great potential for practical environmental applications.