Q.Write short note on microbial fuel cell.

Microbial Fuel Cells

What if the tiny microbes that rot our waste could be made to hand us electricity while they eat? That is exactly the idea behind a microbial fuel cell (MFC) — a device that turns the chemical energy locked in organic matter directly into electrical energy, using living microorganisms as the catalyst.

The core idea — respiration as a battery

When microbes break down organic substrates (sugars, waste, sewage), their metabolism strips electrons from these food molecules. Normally those electrons are passed to a final acceptor like oxygen inside the cell. In a microbial fuel cell, the trick is to make the microbes hand their electrons to an electrode instead. So the same respiration that would otherwise just release heat is redirected to produce an electric current.

How it is arranged

An MFC has two compartments:

• Anode chamber (anaerobic): microbes oxidise the organic substrate, releasing electrons and protons (H⁺). The electrons are captured by the anode.
• Cathode chamber: electrons travel from the anode through an external circuit (doing useful electrical work on the way) to the cathode, where they combine with protons and oxygen to form water.
• The protons pass across a membrane separating the two chambers, completing the circuit.

The electron flow through the wire is the electricity we harvest.

Why microbial fuel cells are attractive

• They can generate power from wastewater and organic waste, treating the waste and producing energy at the same time — a double benefit. …