Guide

Main Module | Energy from Mud? Thank a Microbe!
11
Background
backGrouNd
WhatareMicrobialFuelCells?
Whataremicrobes?
The term microbe, short for microorganism, is used to describe any tiny organism that
is too small individually to be seen with the naked eye. To see a microbe you need
to use a powerful microscope. Microbes are often
associated with disease or illness, but microbes are
also essential players in the recycling of nutrients on
earth and in providing key ingredients necessary to
support life. There are three main types of microbes:
bacteria, fungi and viruses but in MFCs, bacteria are
the key players, so we will limit our discussion to
bacteria.
Bacteria are the most dominant and diverse type of
organism on Earth. Bacteria have dominated since
life on Earth began and have been found in every
imaginable type of environment, even those thought
to be uninhabitable, like acid pools and super-hot
thermal vents.
For more information see Sub-Module 1: Meet the Microbes
Howdomicrobesgettheirenergy?
All living organisms need energy to live. This energy comes from the energy stored in
the chemical bonds of food that is released when we “burn” the fuel.
How different organisms get their food
Some organisms are autotrophs, meaning they take inorganic materials from the
environment to make organic material, or food for themselves, from which they can
then get energy to live.
Plants and certain bacteria
photosynthesize. During photosynthesis
plants take in carbon dioxide and water
and use the sun’s energy to rearrange
these molecules to make organic
matter/food (simple sugars) and oxygen
is given off as a waste product.
Photo by PeskyPlummer (Own work) [CC BY-
SA 3.0 (http://creativecommons.org/licenses/
by-sa/3.0)], via Wikimedia Commons
Photosynthesis