Systematic Full-Cycle Engineering Microbial Biofilms to Boost Electricity Production in Shewanella oneidensis

Area of Science:

• Microbiology
• Bioelectrochemistry
• Synthetic Biology

Background:

• Electroactive biofilms are critical for electron transfer efficiency in microbial electrochemical systems (MES).
• Low biofilm formation ability and conductivity limit extracellular electron transfer rates in MES.
• Shewanella oneidensis is a model exoelectrogen used in MES applications.

Purpose of the Study:

• To engineer Shewanella oneidensis using synthetic biology to enhance biofilm formation and conductivity.
• To improve the extracellular electron transfer rate and power output of microbial electrochemical systems.

Main Methods:

• Systematic engineering of Shewanella oneidensis via modular manipulation of biofilm formation stages.
• Engineering involved modifying initial contact, cell adhesion, biofilm growth, maturation, and cell dispersion.
• Utilized synthetic biology approaches for targeted genetic modification.

Main Results:

• The engineered Shewanella oneidensis biofilms exhibited significantly enhanced formation and conductivity.
• Achieved a maximum output power density of 3.62 ± 0.06 W m⁻².
• This represents a 39.3-fold increase compared to the wild-type strain, a record for engineered Shewanella biofilms.

Conclusions:

• Synthetic biology is effective in enhancing electroactive biofilm performance in MES.
• Engineered Shewanella oneidensis biofilms demonstrate a substantial improvement in power density.
• This work sets a new benchmark for power output in genetically modified Shewanella strains for MES applications.