1) The document discusses different types of microbes including bacteria, archaea, protists and their characteristics. It focuses on archaea, which are single-celled organisms that differ from bacteria and eukaryotes in their biochemistry and evolution. 2) An activity is described where lactobacilli, a type of useful bacteria found in butter milk, are observed under a microscope after staining. The rod-shaped, gram-positive lactobacilli appear dark blue. 3) Lactobacilli are important in fermenting foods like yogurt and buttermilk from milk. They convert lactose into lactic acid, lowering the pH and causing coagulation of milk proteins. This process

1. USEFULAND
HARMFUL MICROBES
-By Dr.K.B.Gabhane
-Assistant Professor,
-Vidyabharti College of Pharmacy, Amrav

2. Types of Microbes
Microorganisms are divided into different types:
1. Bacteria
2. Fungi
3. Viruses
4. Archaea and
5. Protists

3.  Archaea constitutes a domain of single-celled organisms.
 Earlier, Archaea were classified as bacteria, but now it is outdated as it has been found
that they both have different biochemistry and different evolutionary history.
 They are single-celled organisms that comprise cells with distinct properties that make
them unique from the other two domains of life, namely Eukaryota and Bacteria.
 Basic Facts
 They live in extreme environments (like hot springs or salty lakes)
 Normal environments (like soil and ocean water
 Some have a flagella that aids in their locomotion
Types of Microbes : Archaea

4. The hierarchy of biological classification's
Main taxonomic ranks

5. Some weird things about this kingdom:
1. Most don’t need oxygen to survive
2. They can produce ATP (energy) from sunlight
3. They can survive enormous temperature extremes.
4. They can survive high doses of radiation
(radioactivity)
5. They can survive under rocks and in ocean floor
vents deep below the ocean’s surface.
6. They can tolerate huge pressure differences
7. Methanogens are the only archaea that have been
identified in humans, despite human contact with
other archaeal types
8. Anaerobes usually act as opportunists
Types of Microbes : Archaea

6.  Protists are simple eukaryotic organisms that
are neither plants nor animals or fungi.
 Protists are unicellular in nature but can also be
found as a colony of cells.
 Most protists live in water, damp terrestrial
environments or even as parasites.
Types of Microbes : Protists
Classification of Protista : Kingdom Protista is classified into the following
1. Protozoa
2. Slime Moulds
3. Chrysophytes, Dinoflagellates and Euglenoids (Algae)
Chrysophytes : Yellow –Green Al

7. Activity Based Learning :
Aim : To observe bacteria in Butter Milk
Useful Microbes : Lacto Bacilli

8. Useful Microbes : Lacto Bacilli
Requirements : Butter milk, Dropper, crystal violet dye, permanent
Slide, Cover Slip,
Lamp and Microscope

9. Useful Microbes : Lacto Bacilli
Procedure :
Step I - Add 2 to 3 drops of drops of butter milk on cover slip

10. Useful Microbes : Lacto Bacilli
Procedure :
Step II - Heat the slide for about 3 to 4 seconds on flame

11. Useful Microbes : Lacto Bacilli
Procedure :
Step III – Add few drops of crystal violet and cover it with cover slip.

12. Useful Microbes : Lacto Bacilli
Procedure :
Step IV – Leave the slide for 30 to 40 seconds and later wash it with
running water

13. Useful Microbes : Lacto Bacilli
Procedure :
Step V – Place the slide under the microscope and observe it
Observations : Dark Blue coloured structures are observed under microsco

14. Useful Microbes : Lacto Bacilli
Conclusion : Dark Blue coloured bacteria's are present in butter milk

15. Why bacteria showed coloration to
crystal violet dye ?
The crystal violet form large complexes which bind
to the cell and turn it purple. The cells are then
washed with alcohol which strips outer lipid layers
away from the cell.
1. Based on staining property bacterias are classified
as Gram Positive and Gram negative bacterias.
2. The gram-positive bacteria retain the crystal violet
colour and stains purple whereas the gram-
negative bacteria lose crystal violet and stain red.
3. Thus, the two types of bacteria are distinguished
by gram staining.
4. Gram-negative bacteria are more resistant against
antibodies because their cell wall is impenetrable.

17. Lacto Bacilli
The blue colored rod-shaped organisms moving around under microscope are lactobacilli, a
kind of bacteria.
Characteristics of Lactobacilli
1. Lactobacillus is a Gram-positive, aerotolerant
anaerobes or microaerophilic, rod-shaped, non-
spore-forming bacteria.
2. These are "friendly" bacteria that normally live in
our digestive, urinary, and genital systems without
causing disease.

18. 3. Lactobacillus is most commonly used for diarrhea, including infectious diarrhea and
diarrhea in people taking antibiotics (antibiotic-associated diarrhea).
4. Some people also used lactobacillus for general digestion problems, a long-term
disorder of the large intestines that causes stomach pain (irritable bowel
syndrome or IBS) , excessive crying in infants (colic), long-term swelling
(inflammation) in the digestive tract (inflammatory bowel
disease or IBD), inflammation of the colon, and many other conditions, but there is no
good scientific evidence to support many of these uses.
5. Lactobacillus is also in some fermented foods like yogurt and in dietary
supplements.
Characteristics of Lactobacilli

19. How is yoghurt made from milk?
The lactobacilli convert
lactose into lactic acid
This process is called
Fermentation
Decrease in the pH of milk causing
coagulation of milk proteins
Milk proteins are separated from other
constituents of milk.
Milk Changes Into Yoghurt.
Results in
Yoghurt has a
specific sour taste
due to lactic acid.
The low pH
destroys harmful
microbes present
in the milk.

20. Uses of Lactobacilli :
1. Various milk products like yoghurt, buttermilk, ghee, cheese, shrikhand, etc. can be
obtained by fermentation of milk.
2. Lactobacilli fermentation is useful for large scale production of cider, cocoa, pickles
of vegetables, etc.
3. Lactobacilli and some other useful microbes taken together are used to treat
abdominal discomfort.
4. Leavened fodder offered to domestic cattle like cows and buffalos, is fermented with
the help of lactobacilli.
5. The lactobacilli fermentation process is used to make wine and some types of bread.

21.  Why do doctors advise you to have yoghurt or buttermilk if you have indigestion or
abdominal discomfort?
 Sometimes, yoghurt becomes bitter and froths up. Why does this happen?
 Which different milk products are obtained at home by fermentation of the cream
from the milk?
 What is meant by ‘probiotic’ yoghurt and other foodstuffs that are popular
nowadays?
 How many different industries depend upon the lactobacilli bacteria?
 Which types of cottage industries and factories can be started in areas with abundant
milk production?
QUESTIONARIES

22. THANK-YOU