There are billions of microbes that have not been discovered yet. Many microbes are necessary for human survival or are beneficial. Microbes can be used for industrial purposes. In nature, microbes help plants grow through interactions in soil and some produce oxygen. Microbes are essential for decomposition which recycles nutrients. In food, microbes are used to make yogurt, cheese, bread, and alcohol through fermentation. Important microbes in medicine include penicillin-producing fungi and microbes used in vaccines. Probiotics are live microbes that benefit human health by interacting with pathogens, reinforcing barriers, competing for resources, and strengthening the immune system.

1. Useful Microbes
Microbes can be beneficial to us?!?

2. 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

3. In Nature
Microbe – plant Interaction
– Many microbes are found in
nature and help plants to
grow
– Rhizobacteria found in the
soil fixate nitrogen which is
required for many crops to
grow
Roots
Microbes

4. In Nature
• Oxygen production
– Cyanobacteria or
‘blue-green algae’
produce oxygen in
the ocean

5. 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.

6. 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!
• Bread and dough products
– Yeast is used to make bread and
dough products.
• Alcohol Production
– Yeast is also used in alcohol
production when fermentation occurs
without air
Lactobacilli bacteria used in
yogurt and cheese making
Saccharomyces cerevisiae yeast
used in bread making and
alcohol production

7. 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.

8. 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

9. 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

10. 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