Microbial diversity includes microorganism’s distribution in nature, their
relationship with each other and other living organisms, their effects on
human beings and other animals and plants.
They are closely associated with the health and welfare of human beings.
The study of bacteria & the subdivision of microbiology involves the
identification, classification, and characterization of bacterial species.
Important genera & species in Bacteriology:
• Pseudomonaceae: Pseudomonas flurescens
• Halobacteriaceae: Halobacterium salinarium
• Escherichia : Escherichia coli
• Lactobacillaceae: Lactobacillus lactis
• Streptococcaceae : Streptococcus lactis
• Clostridium: Clostridium botulinum
Habitat of Bacteria
• Bacteria widely distributed in soil and water, or with other
• Human body also has a considerable number of bacteria.
• It is estimated that the human body and the skin on the total
number of bacterial cells is about ten times the total number of
• There are also some species found in extreme environments, such
as hot springs, they are classified as extremophiles, which is one of
the most famous types of habitat .
The yellow stuff is
Papillomavirus Genital infections and cervical cancer
Adenovirus Respiratory and gastrointestinal disease
Reovirus Respiratory and gastrointestinal disease
Calicivirus Gastrointestinal disease
Enterovirus Gastrointestinal disease, poliomyelitis
Rhinovirus Common cold
Hepatitis B virus Liver infection
Smallpox virus Smallpox
Some common virus & their effect
Habitat of Viruses
Viruses are not able to survive with out a host cell, and thus active
viruses reside inside a host body. They effect on host vary as well. They
can lower host immunity
• A fungus is a member of a large group of eukaryotic organisms
that includes microorganisms such as yeasts and molds.
• These organisms are classified as a kingdom, Fungi.
Habitat & Distribution
• Fungi have a worldwide distribution, and grow in a wide
range of habitats, including extreme environments such as
deserts or areas with high salt concentrations or ionizing
radiation, as well as in deep sea sediments.
• Most grow in terrestrial environments, though several
species live partly or solely in aquatic habitats.
• Around 100,000 species of fungi have been formally
described by taxonomists.
• The fungal kingdom has been estimated to contain about
1.5 million species.
The term mold is applied to a large and
taxonomically diverse number of fungal
species where their growth results in a
moldy appearance of objects, especially
A clementine covered
with mold Mold in Petridis
• Yeasts are eukaryotic microorganisms, classified in the Kingdom
• Yeasts are unicellular, although some species with yeast forms
may become multicellular
• Use organic compounds as a
source of energy
• Do not require sunlight to grow
• Carbon is obtained mostly from
hexose sugars, such as glucose
• Grow best in a neutral or
slightly acidic pH environment.
• Some species can metabolize
pentose sugars like ribose,
alcohols, and organic acids
In bakery industries.
Producing Alcoholic beverages like mead, Beer , Wine
In food spoilage.
Saccharomyces cerevisiae, is used in baking as a
Brewer's yeast is also very rich in essential minerals
and the B vitamins(except B12)