A microbial fuel cell operating at low pH using the acidophile Acidiphilium cryptum

Area of Science:

• Microbial electrochemistry
• Bioenergy research
• Acidophile microbiology

Background:

• Microbial fuel cells (MFCs) offer a sustainable energy source.
• Acidophiles, microorganisms thriving in acidic environments, present unique metabolic capabilities.
• Iron is a common natural electron acceptor for some microorganisms.

Purpose of the Study:

• To develop a microbial fuel cell (MFC) utilizing the acidophile Acidiphilium cryptum as an anode biocatalyst.
• To investigate electricity generation using iron as a natural electron mediator at low pH.
• To enhance power output through the use of artificial electron mediators.

Main Methods:

• Construction of a two-chamber air-sparged microbial fuel cell.
• Utilizing Acidiphilium cryptum as the anode biocatalyst.
• Employing iron as the natural electron mediator and evaluating artificial mediators like nitrilotriacetic acid and Phenosafranin.

Main Results:

• Electricity production was demonstrated using Acidiphilium cryptum at pH values <= 4.0 with iron as the electron mediator.
• Fe(III) accumulation at the electrode limited the initial current output.
• The addition of nitrilotriacetic acid and Phenosafranin significantly increased power output to 12.7 mW/m(2).

Conclusions:

• Acidiphilium cryptum can function as an effective anode biocatalyst in microbial fuel cells under acidic conditions.
• Artificial electron mediators are crucial for overcoming limitations posed by natural electron acceptors like iron and enhancing power generation.
• Further research is needed to optimize direct electron transfer mechanisms for improved MFC performance.