Developing a population-state decision system for intelligently reprogramming extracellular electron transfer in...

Area of Science:

• Microbiology
• Bioengineering
• Environmental Science

Background:

• Electroactive bacteria (EAB) are crucial for environmental and energy applications due to their extracellular electron transfer (EET) capabilities.
• Genetic engineering of EAB for enhanced EET often compromises cellular metabolism and growth.
• Limited cellular resources create a bottleneck for simultaneous growth and high EET.

Purpose of the Study:

• To engineer a novel system for intelligent regulation of EET in EAB.
• To rebalance cellular resource allocation based on bacterial population state.
• To enhance EET and pollutant reduction capabilities without impairing bacterial growth.

Main Methods:

• Designed a quorum sensing-based population-state decision (PSD) system.
• Reprogrammed the EET regulation system in *Shewanella oneidensis* MR-1.
• Shifted metabolic flux from growth to EET based on population density.

Main Results:

• The PSD system significantly enhanced EET, achieving up to a 4.8-fold increase.
• Engineered bacteria showed vastly improved pollutant reduction: 18.8-fold for methyl orange and 5.5-fold for hexavalent chromium.
• The PSD system outperformed constant expression systems in EET enhancement and pollutant bioreduction.

Conclusions:

• The PSD system enables intelligent management of EET by dynamically reallocating cellular resources.
• This approach overcomes limitations of previous genetic engineering strategies for EAB.
• The PSD system offers a powerful tool for bioelectrical devices and environmental remediation.