Engineering a Native Inducible Expression System in Shewanella oneidensis to Control Extracellular Electron Transfer

Area of Science:

• Microbiology
• Biotechnology
• Bioelectrochemistry

Background:

• Shewanella oneidensis MR-1 is a model organism for studying extracellular electron transport.
• Applications in wastewater treatment, bioremediation, and biosensors leverage Shewanella's respiratory capabilities.
• Engineering gene expression in S. oneidensis often relies on foreign regulatory systems.

Purpose of the Study:

• To characterize a native S. oneidensis pathway for gene expression induction using trimethylamine N-oxide (TMAO).
• To engineer S. oneidensis strains where extracellular electron transfer is controlled by TMAO.
• To assess the inducibility of this pathway through iron reduction and anodic current measurements.

Main Methods:

• Characterization of a native S. oneidensis gene expression pathway.
• Engineering of S. oneidensis strains for TMAO-inducible extracellular electron transfer.
• Measurement of iron reduction rates.
• Analysis of anodic current produced by bioreactor-grown cells.

Main Results:

• A native S. oneidensis pathway inducible by trimethylamine N-oxide was identified and characterized.
• Engineered strains demonstrated TMAO-controlled extracellular electron transfer.
• Iron reduction and anodic current measurements confirmed the pathway's inducibility.

Conclusions:

• A native TMAO-inducible pathway offers a new tool for engineering Shewanella oneidensis.
• This system allows for precise control of extracellular electron transfer, enhancing biotechnological potential.
• The developed strains are suitable for applications requiring regulated bioelectrochemical activity.