Engineered Escherichia coli Modified with Carbon Quantum Dots as a High-Performance Cathode Catalyst for Microbial...

Area of Science:

• Biotechnology
• Materials Science
• Electrochemistry

Background:

• Nanomaterial modification of natural cells enhances biocatalytic activity for energy and pollution treatment.
• Chemically engineered biocatalyst systems are still in early development stages.

Purpose of the Study:

• To develop an efficient biocatalyst by incorporating carbon quantum dots (CDs) into Escherichia coli (E. coli).
• To enhance the oxygen reduction reaction (ORR) at the cathode of microbial fuel cells (MFCs).

Main Methods:

• Incorporation of carbon quantum dots (CDs) into Escherichia coli (E. coli).
• Electrochemical measurements to assess ORR activity and MFC performance.
• Analysis of extracellular electron transfer, metabolic activity, ATP levels, and surface properties.

Main Results:

• Engineered E. coli showed accelerated electron transfer, increased metabolic activity, and higher ATP levels.
• Enhanced surface adhesion and electronegativity were observed in the modified E. coli.
• Superior ORR activity with a maximum current density of 3.1 mA·cm⁻² and onset potential of 0.67 V.
• MFCs utilizing the modified biocatalyst achieved a maximum power density of 325 μW·cm⁻².

Conclusions:

• Carbon quantum dot incorporation provides a facile and cost-effective method for improving MFC performance.
• The engineered E. coli serves as a promising biohybrid catalyst for next-generation energy applications.
• This strategy offers a significant advancement in the development of chemically engineered biocatalyst systems.