Useful Microbes
Microbes can be beneficial to us?!?
Useful Microbes
There are billions of microbes and lots more we
haven’t discovered yet
Most of these microbes are either
• Necessary for our survival
• Good for us
• Can be used for our benefit in industry
In Nature
Microbe – plant Interaction
– Many microbes are found in
nature and help plants to
grow
Roots
– Rhizobacteria found in the
soil fixate nitrogen which is
required for many crops to
grow
Microbes
In Nature
• Oxygen production
– Cyanobacteria or
‘blue-green algae’
produce oxygen in
the ocean
In Nature
• Decomposition
– Defined as the breakdown of raw
organic materials to a finished
compost
– The fungi invade the organic
matter in soils first and are then
followed by bacteria.
– Without this recycling of inorganic
nutrients, primary productivity on
the globe would stop.
In the Food Industry
• Cheese and yogurt
– Lactic acid fermentation produces
yogurt and cheese. Some fungi are
also used to make the cheese turn
blue!
Lactobacilli bacteria used in
yogurt and cheese making
• Bread and dough products
– Yeast is used to make bread and
dough products.
• Alcohol Production
– Yeast is also used in alcohol
production when fermentation occursSaccharomyces cerevisiae yeast
used in bread making and
without air
alcohol production
In the Food Industry
• Fermentation
– A process during which the bacteria break
down the complex sugars into simple
compounds like carbon dioxide and alcohol.
– Fermentation changes the product from one
food to another.
In Medicine
• Penicillin
– Discovered by Alexander
Flemming in 1928
– Produced by the fungus
Penicillium notatum
– One of the most commonly used
antibiotics today
• Vaccines
– Discovered by Edward Jenner in 1796
– Usually made from weak or inactive
versions of the same microbes that
make us ill
The fungus Penicillium produces
the antibiotic Penicillin
Probiotics
• What are they?
– Live microorganisms which when
administered in adequate amount
confer a health benefit on the
host
• What type of bacteria are they?
– Lactobacilli which are part of the
beneficial natural microflora
found in the human gut
Probiotics
How do they work?
– Interacting directly with the disease-causing microbes,
making it harder for them to cause disease
– Reinforce the natural barrier of the digestive tract
protecting against pathogenic microbes
– "Competitive exclusion" in which beneficial microbes
directly compete with disease-causing microbes for food
and other resources, eventually crowding them out
– Interacting with and strengthening the immune system