Microbiology

DHIRAJ WASULE
ASSISTANT PROFESSOR
VNCAB, YAVATMAL
MICROBIOLOGY

Microbiology - Microbiology (from Greek mīkros,
"small"; bios, "life"; and -logia) is the study
of microorganisms, those being unicellular(single
cell), multicellular (cell colony), or acellular (lacking cells).

Character Prokaryotes Eukaryotes
Nucleus Absent Nuclear envelope and nucleolus
Membrane-
bound
organelles
Absent Present. Includes mitochondria,
chloroplasts (plants), lysosomes
Chromosome
(DNA)
Single coiled chromosome in
cytoplasm ‘nucleoid’ region
Multiple linear chromosomes
with histone proteins
Cell wall Eubacteria have a cell wall of
peptidoglycan Archaea have cell walls
of pseudomurein
No cell wall in animal cells
Plant cell walls = cellulose
Fungal cell walls = chitin
Mitotic division Absent Present
Ribosomes 70S. Free in cytoplasm 80S. Both free in cytoplasm and
attached to rough E.R.
Flagella when present consist of protein
flagellin
consist of 9+2 arrangement of
microtubules
Mitochondria Absent Present
Lysosomes Absent Present
Golgi apparatus Absent Present
Endoplasmic
Reticulum
Absent Present

1665 – Robert Hooke – Start of cell theory
1676 – Anton van Leeuwenhoek, first person to observe and
describe microorganisms (MO), often referred to as the “Father of
Microbiology.”
History
• First to observe living microbes
• His single-lens magnified 50-300X
magnification
• Between 1674-1723 he wrote series of
papers describing his observations of
bacteria, algae, protozoa, and fungi
(Animalcules)
ANTONY VAN LEEUWENHOEK

Spontaneous Generation -Theory that living organisms arise from
non-living material
382-322 B.C. Aristotle - Spontaneous generation.
1626-1697 Francisco Redi - Demonstrated that flies did not arise
spontaneously from rotting meat.
1731-1781 John Needham- Claimed existence of a "life force"
present in inorganic matter that could
cause spontaneous generation.
1729-1799 Lazzaro Spallanzani – Claimed Needham's organisms
came from heat resistant microbes
History

LOUIS PASTEUR (1822 - 1895)
“Father of bacteriology and immunology”
 Disproved spontaneous generation
of microbes by preventing “dust
particles” from reaching the sterile
broth
 In 1861 completes experiments that
lays to rest spontaneous generation
 Showed microbes caused
fermentation and spoilage
History

Developed the germ theory in 1798
Developed vaccine against anthrax.
1885 - Vaccine against Rabies
Discovered that parasites (protozoa) causing pebrine
disease of silk worm
Pasteurization technique
Pasteur demonstrated that Bacteria that use alcohol and produce
acetic acid spoil wine by turning it to vinegar (acetic acid).
 spoilage bacteria could be killed by heat that was not hot
enough to evaporate the alcohol in wine.
Application of a high heat for a short time is called
pasteurization. Heating the juice at 62.8°C for half-an hour did the
job
Louis Pasteur
History

Germ Theory of Disease
1834 Bossi – Discovered Silkworm disease – fungus
1846 Berkeley – Discovered Potato blight – fungus
1846 Ignaz Semmelweis – Discovered Hand washing in hospitals
1857 Louis Pasteur – Discovered Bacteria cause diseases in wine
1867 Joseph Lister – Discovered antiseptic surgery
1870’s Robert Koch – Discovered staining microorganisms
Semi-solid media for growth (agar), Pure culture
techniques, Streak plates, pour plates, slant
cultures, Nutrient broth/agar
1876 – proved a specific bacteria was the cause of
anthrax Identified cause of anthrax
(Bacillus anthrax), TB (Mycobacterium tubercullosis)
& cholera ( Vibrio cholera).
History

• 1884 Koch’s Postulates of Disease Transmission
ROBERT KOCH
 The causative (etiological) agent must be present in all
affected organisms but absent in healthy individuals
 The agent must be capable of being isolated and cultured in
pure form
 When the cultured agent is introduced to a healthy organism,
the same disease must occur
 The same causative agent must be isolated again from the
affected host
History

JOHN TYNDALL (1820 – 1893)
• In 1876 discovered that there were two
different types of bacteria.
• a) Heat sensitive or heat labile forms
(vegetative cells)
easily destroyed by boiling
• b) Heat resistant types known as an
endospore
• Tyndall demonstrated that alternate
process of heating & cooling if
repeated five times, can kill all the
endospores.
• This is known as Sterilization
process or Tyndallization
History

1928: Alexander Fleming
discovered the first antibiotic.
He observed that Penicillium
fungus made an antibiotic,
penicillin, that killed S. aureus.
1940s: Penicillin was tested
clinically and mass produced.
History

History
Immunology
1798 Edward Jenner cowpox used as vaccine for smallpox
1886 Louis Pasteur attenuated vaccines, Fowl cholera,
rabies, anthrax
1890 Behring and
Kitasato
diphtheria antitoxin – gamma globulin
1884 Metchnikoff discovers phagocytosis
1900 Paul Ehrlich discovers antibodies
Chemotherapy
1910 Paul Ehrlich develops arsenic compound to
treat syphilis
1928 Alexander Fleming discovered penicillin
1940’s Florey production of penicillin
1935 Domagk sulfa drugs

General Microbiology
1805 Nicholas Appert – heat canning for food preservation
D. Iwanowsky – used filter techniques of Pasteur to
discover viruses
S. Winogradsky (1856-1953)
M. Beijerinck (1851-1931)
Their discoveries include:
1. Role MO play in carbon, nitrogen, sulfur cycles of the earth cycles
of the earth
2. Bacteria can live in inorganic environments
3. Enrichment techniques
The word "protozoa" (singular protozoon or protozoan) was coined in
1818 by Georg August Goldfuss
Otto Bollinger Discovery of Actinomycetes 1877
Howard Taylor Ricketts Discovery of Rickettsia 1910
S.B. Prussiner Discovery of Prions 1997
Theodor Otto Diener discovery of Viroids 1971
History

• Reska (1938) – First Electron
Microscope
• The electron microscope is capable
of magnifying biological specimens
up to one million times. These
computer enhanced images of 1.
smallpox, 2. herpes simplex, and 3.
mumps are magnified, respectively,
150,000, 150,000 and 90,000 times.
• To study detail structures of
viruses.
History

In 1953 Watson and Crick determined
the structure of DNA. They used their
research, together with the research of
Franklin and Wilkins to determine the
structure of the DNA molecule.
Frederick Griffith (1928) they provided
evidence that deoxyribonucleic acid
(DNA) was the genetic material and
carried genetic information during
transformation. Worked with
Streptococcus pneumoniae (rough and
smooth)
History

Shapes of Bacteria
• Coccus
– Chain = Streptoccus
– Cluster = Staphylococcus
• Bacillus
– Chain = Streptobacillus
• Coccobacillus
• Vibrio = curved
• Spirillum
• Spirochete
• Square
• Star
Bacteria

Bacteria Shapes and Arrangements

Bacterial Structures
• Flagella
• Pili
• Capsule
• Plasma Membrane
• Cytoplasm
• Cell Wall
• Lipopolysaccharides
• Teichoic Acids
• Inclusions
• Spores
Bacteria

Flagella
• Motility - movement
• Swarming occurs with some bacteria
• Arrangement basis for classification
– Monotrichous; 1 flagella
– Lophotrichous; tuft at one end
– Amphitrichous; both ends
– Peritrichous; all around bacteria
Bacteria

Pilli
• Short protein appendages smaller than flagella
• Adhere bacteria to surfaces
– Antibodies to will block adherance
• F-pilus; used in conjugation
– Exchange of genetic information
• Flotation; increase boyancy
– Pellicle (scum on water),
– More oxygen on surface
Bacteria

Capsule or Slime Layer
• Glycocalyx - Polysaccharide on external
surface
• Adhere bacteria to surface
– S. mutans and enamel of teeth
• Prevents Phagocytosis
– Complement can’t penetrate sugars
Bacteria

Cytoplasm
• 80% Water {20% Salts-Proteins)
– Osmotic Shock important
• DNA is circular, Haploid
– Advantages of 1N DNA over 2N DNA
– More efficient; grows quicker
– Mutations allow adaptation to environment quicker
• Plasmids; extra circular DNA
– Antibiotic Resistance
• No organelles (Mitochondria, Golgi, etc.)
Bacteria

Cell Membrane
• Bilayer Phospholipid
• Water can penetrate
• Flexible
• Not strong, ruptures easily
– Osmotic Pressure created by cytoplasm
Bacteria

Cell Wall
• Peptido-glycan Polymer (amino acids + sugars)
• Unique to bacteria
• Sugars; NAG & NAM
– N-acetylglucosamine
– N-acetymuramic acid
• D form of Amino acids used not L form
– Hard to break down D form
• Amino acids cross link NAG & NAM
Bacteria

Chapter 4
Lipopolysaccharide (LPS)
• Endotoxin or Pyrogen
– Fever causing
– Toxin nomenclature
• Endo- part of bacteria
• Exo- excreted into environment
• Structure
– Lipid A
– Polysaccharide
• O Antigen of E. coli, Salmonella
• G- bacteria only
– Alcohol/Acetone removes
Bacteria

Endospores
• Resistant structure
– Heat, irradiation, cold
– Boiling >1 hr still viable
• Takes time and energy to make spores
• Location important in classification
– Central, Subterminal, Terminal
• Bacillus stearothermophilus -spores
– Used for quality control of heat sterilization
equipment
• Bacillus anthracis - spores
– Used in biological warfare
Bacteria

Bacteria
• Bacteria divide by binary fission
• Alternative means
– Budding
– Conidiospores
(filamentous bacteria)
– Fragmentation

Generation Time
• Time required for cell to divide/for population to
double
• Average for bacteria is 1-3 hours
• E. coli generation time = 20 min
– 20 generations (7 hours), 1 cell becomes 1 million
cells!

• Commonly known as blue-green algae.
• Autotrophic (Photosynthetic).
• Contain chlorophyll a, phycocyanin (blue) and
phycoerythrin (red).
• They live in aquatic environments including
oceans, ponds, lakes, tidal flats, and moist soil.
• They exist mostly as colonies and filaments
and sometimes as single cells.
Cyanobacteria

Cell structure
• The cell structure is very primitive.
• Each cell is composed of two parts:
a) cell wall
b) protoplast.
The cell wall is composed of 2 layers:
The inner layer of which is thin and firm
composed of peptidoglycan.
The outer layer of the wall is thicker and
gelatinous known as the sheath and
mainly constituted of pectic compounds.
Anabaena sp, Gloeocapsa sp, Microcystis sp
Stigonema sp
Chromoplast
Central body
Cell wall
Cyanobacteria

Nostoc
• Grows in water and on damp soils.
• Unbranched filaments with barrel-like cells.
• Certain enlarged cells appear at intervals,
which are known as heterocysts . Its
transparent and thick walls.
• The whole filament is surrounded with
gelatinous material.
Reproduction in by fission.
Prokaryotic cell.
Lack chlorophyll b.
Nostoc

• Nitrogen fixation
• Can be used as food (Japan, Chad, and China)
• Can pollute the water source (Lake).
• High concentration may cause fish toxicity and other
microorganism.
Reproduction
1. Vegetative reproduction.
Sexual reproduction is not known.
2. Asexual reproduction.
B) By Akinetes.A) By fission.
Importance of Cyanobacteria

• Prokaryotic
• Lack peptidoglycan
• Live in extreme
environments
• Include:
– Methanogens
– Extreme halophiles
– Extreme thermophiles
Archaea

Bacteriophage means to eat bacteria,
and are called so because virulent
bacteriophage can cause the compete
lysis of a susceptible bacterial culture.
They are commonly referred as
“phage”. Phages are obligate
intracellular parasites that multiply
inside bacteria by making use of some
or all of the host biosynthetic
machinery
Bacteriophage

Adsortion
Penetration
Replication
Maturation
Release

71
• Eukaryotes
• Chitin cell walls
• Use organic chemicals for
energy
• Molds and mushrooms
are multicellular
consisting of masses of
mycelia, which are
composed of filaments
called hyphae
• Yeasts are unicellular
Fungi

Importance of fungi:
i. Important agents for biodegradation and bio-
deterioration
ii. Use in industrial fermentation process.
•Examples; Penicillium notatum is used for production of
penicillin antibiotics
•Aspergillus niger is used for prodution of citric acid
•Saccharomyces cerevisiae is used for alcohol production
iii. Used in bioremediation (reduces toxic concentration)
iv. Used in agriculture, horticulture and forestry, example;
biofertilizer and biopesticides
Fungi

Fungi are Eukaryotic organism
1. Morphology:
•Fungi exists in two fundamental forms, filamentous or hyphal
form (MOLD) and singe celled or budding form (YEAST).
•But for the classification of fungi, they are studied as mold,
yeast, yeast like fungi and dimorphic fungi.
•Yeast is Unicellular while Mold is multicellular and filamentous
2. Fungi lack Chloroplast.
3. Mode of nutrition:
•Fungi are organotropic heterotrophs.
•Mostly Fungi are saprophytic and some are Parasitic
4. Fungi grow best in acidic environment (tolerate acidic pH).
5. Fungi can tolerate high sugar concentration and dry condition
6. Most of the fungi are Obligate aerobes (molds) and few are
facultative anaerobes (yeasts)
7. Optimum temperature of growth for most saprophytic fungi
is 20-30 C while (30-37) C for parasitic fungi.
Characteristics of Fungi

8. Growth rate of fungi is slower than that of bacteria.
9. Cell wall is composed of chitin
10. Cell membrane consists of ergosterol
11. Reproduction: both asexual (Axamorph) and sexual (Teliomorph)
mode of reproduction
•Asexual methods: fragmentation, somatic budding, fission, asexual
spore formation
•Sexual methods: gametic copulation, gamate-gametangium
copulation, gametangium copulation, somatic copulation and
Spermatization.
12. More than 2,00,000 fungi species are known.
13. More than 100 fungi are responsible for human infection.
14. More than 20 species are responsible to cause severe systemic
human infection, 35 species causes less severe systemic disease or
might causes cutaneous or sub cutaneous infection and 45 species
causes superficial cutaneous infection.
15. Some fungi shows mutualistic relationship with higher plants, eg
Mycorrhiza is symbiotic associated with root of gymnosperm.
Characteristics of Fungi

• hyphae - the vegetative bodies of most fungi, constructed of
tiny filaments
• mycelium -an interwoven mat of hyphae
Fungi

Septate hypha:
• multicellular
• walls divided by septa
Ceonocytic hypha:
• continuous cytoplasm
mass
• multinucleate
• no septa
Fungi

Haustoria:
• Modified hyphae found in parasitic fungi
• Function: absorb nutrients from host
• Some fungi even have hyphae adapted for preying on
animals.
Fungi

Sporangium Conidia on hyphae
Sporangiospore
or just “spore”
Conidium
Sporangiophore
Conidiophore
Types of Asexual Spores
Fungi

• The zygomycete Rhizopus can reproduce either
asexually or sexually.
Fungi

86
• Eukaryotes
• Cellulose cell walls
• Use photosynthesis
for energy
• Produce molecular
oxygen and organic
compounds
Volvox
Algae

Basic virus particle is called a “virion” – intact and infective virus
particle
Components: Nucleic Acid (DNA or RNA), Protein coat (capsid) made
of individual protein subunits called capsomeres. Some may have
and outer envelope, a membrane, derived from the host cell. The
envelope can have specific spikes of protein (H and N spikes of
Influenza) that aid in attachment and makes them sensitive to
chemical actions of disinfectants.
Viruses

Protozoa
General Characteristics of phylum Protozoa
Kingdom: Protista.
Acellular or non-cellular organism.
Habitat: mostly aquatic, either free living or parasitic or commensal
Grade of organization: protoplasmic grade of organization.
Body of protozoa is either naked or covered by a pellicle.
Locomotion: Locomotory organ are pseudopodia (false foot) or cilia or
absent.
Nutrition: Nutrition are holophytic (like plant) or holozoic (like animal)
or saprophytic or parasitic.
Digestion: digestion is intracellular, occurs in food vacuoles.
Respiration: through the body surface.
Osmoregulation: Contractile vacuoles helps in osmoregulation.
Reproduction:
Asexually reproduction is through binary fission or budding.
Sexual reproduction is by syngamy conjugation.

Biofertilizer: It is a substance which contains living microorganisms which,
when applied to seeds, plant surfaces, or soil, colonizes the rhizosphere or
the interior of the plant and promotes growth by increasing the supply or
availability of primary nutrients to the host plant.
Importance of Biofertilizers in Agriculture:
•Add nutrients through the natural processes of nitrogen fixation,
solubilizing phosphorus, and stimulating plant growth through the
synthesis of growth-promoting substances.
•Reduce the use of chemical fertilizers and pesticides.
•Restore the soil's natural nutrient cycle and build soil organic matter.
•Eco-friendly organic agro-input and are more cost-effective
than chemical fertilizers.
•Bio-fertilizers such as Rhizobium, Azotobacter, Azospirilium and blue
green algae (BGA) have been in use a long time.
•Phosphate-solubilizing bacteria, such as Pseudomonas putida are able
to solubilize the insoluble phosphate from organic and inorganic
phosphate sources.
Biofertilizer

S. No. Groups Examples
N2 fixing Biofertilizers
1 Free-living Azotobacter, Clostridium, Anabaena, Nostoc,
2 Symbiotic Rhizobium, Frankia, Anabaena azollae
3 Associative Symbiotic Azospirillum
P Solubilizing Biofertilizers
1 Bacteria Bacillus megaterium var. phosphaticum
Bacillus circulans, Pseudomonas striata
2 Fungi Penicillium sp, Aspergillus awamori
P Mobilizing Biofertilizers
1 Arbuscular
mycorrhiza
Glomus sp.,Gigaspora sp.,Acaulospora sp.,
Scutellospora sp.and Sclerocystis sp.
2 Ectomycorrhiza Laccaria sp., Pisolithus sp., Boletus sp., Amanita sp.
3 Orchid mycorrhiza Rhizoctonia solani
Biofertilizers for Micro nutrients
1 Silicate and Zinc
Solubilizers
Bacillus sp.
Plant Growth Promoting Rhizobacteria
1 Pseudomonas Pseudomonas fluorescens
Grouped based on their nature and function

What is Nitrogen?
Nitrogen makes up about 78%
of our atmosphere.
Nitrogen in the atmosphere it is mostly in
the form of ______, which is a compound
that plants and animals cannot use.
The process of converting nitrogen into
compounds that can be used by plants and
animals is called the
______________________.
N2
Nitrogen Cycle

Why we care about nitrogen…
Nitrogen is an essential
component of
___________________
__.The building blocks
of life.
DNA, RNA and Proteins

How does atmospheric nitrogen (N2)
get changed into a form that can be
used by most living organisms?
By traveling through one of the
________ processes in the Nitrogen
Cycle!
Nitroge
n Cycle
(1) Nitrogen
Fixation
(2)
Ammonification
(3) Nitrification
(4) Denitrification
Four

Process 1: Nitrogen Fixation
___________________ is the process in
which the N2 compound in the
atmosphere breaks and combines with
other compounds. The nitrogen is
_________ when it combines with
______________ or _______________.
N
N
H
N
HH
N2
Nitrogen Fixation
“fixed”
hydrogen oxygen
Ammonia (NH3)
Nitrous Oxide (N2O)

Three ways to “fix” Nitrogen
Main process: Special
____________ convert the
nitrogen gas (N2) to ammonia (NH3),
which only ________ plants can use
(peas, beans).
_________________ strikes convert
N2 to N2O or NO3.
Industrial production. ____________
manipulation turns N2 into NH3
(Fertilizer)
bacteria
some
Lightning
Chemical

Process 2: Ammonification
_____________________ - After all the living
organisms have used the
___________________, decomposer
bacteria convert the nitrogen to
_______________.
N
H
H
H
Ammonification
organic nitrogen
ammonia
Bacteria Ammonia
Organic Nitrogen (proteins)

Process 3: Nitrification
_______________ is the process
that converts ammonia (NH3) into
nitrites (NO2) and nitrates (NO3)
which ____ plants _______ use.
Note: Ammonia comes from
______ nitrogen fixation and
ammonification
How is it done? N
N
N
H
H
H
O O
O
O O
Nitrification
mostcan
Both
Bacteria!

Process 4: Denitrification
_______________: Process in which
nitrogen compounds
_____________________ into
atmospheric nitrogen (N2 or N2O).
The main process is performed by
_____________________ in the soil. It
can also happen by _____________
fossil fuels.
N2ONO3
N2
Denitrification
convert back
bacteria
burning

Nitrogen
Cycle
(4) Denitrification (1) Nitrogen Fixation
(2) Ammonification
Nitrates in
Soil
Organic nitrogen is
converted to ammonia.
N2
NH3
NO3
N2O
Ammonia is converted
to nitrites and nitrates.
(3) Nitrification

Nitrogen in
the air
animal protein
dead plants & animals
urine & feces
ammonia
nitrites
nitrates
plant made
protein
decomposition by bacteria & fungi
bacteria
(nitrifying bacteria)
nitrates absorbed
denitrifying
bacteriaroot nodules
(containing nitrogen
fixing bacteria)
nitrogen fixing
plant
eg pea, clover
bacteria

Human Impact
___________________, releases toxic nitrogen
compounds into the atmosphere.
____________________________ release
nitrous oxide into the atmosphere and introduce
excess nitrogen into the environment.
Remove nitrogen from the soil when we mine it for
nitrogen rich __________________________.
Discharge of ___________________________
releases excess nitrogen into the water ecosystems
which disrupts the aquatic balance and kills fish.
Combustion
Commercial Fertilizers
mineral deposits
municipal sewage

Commercial Fertilizers
Are the ______ contributor of new nitrogen in
the nitrogen cycle.
Added because nitrogen is a
________________ for plant growth.
Problems: hard to apply fertilizer and keep it in
one area. Runoff, evaporation, etc.. So farmers
apply about ___________________ as they
need.
Extra nitrogen disrupts the ________________.
#1
limiting factor
twice as much
food chain

The Phosphorus Cycle
Start from the
beginning
Make it Rain!
The Producers
The Consumers
The
Decomposers
The Quiz
The Human
Factor

Why is Phosphorus Important?
DNA molecules are made from
three smaller molecules:
(1) Sugar
(2) Nitrogen base
(3) ???
What is the 3rd molecule of
DNA?
Fatty acid
Phosphate
group
Mono-
saccharide
No. Fatty acids are in
lipids.
No. Monosaccharaides
are in carbohydrates.correct
Back Home

ATP is a molecule needed by
cells for _______.
ATP stands for Adenosine
Tri________?
Energy Food
Releasing
CO2
prokaryote
Poly-
saccharide
phosphate
Hint: What does the
mitochondria create?
Hint: What does the
correct
Which choice looks like
“phosphorus?”
Which choice looks like
“phosphorus?”
correct
Back Home

Which part of a cell is semi-permeable
and allows some materials to
enter/exit the cell?
The cell membrane is made from a
double layer of lipids called
“phospholipids.” Which element is
implied by the prefix “phospho?”
Mito-
chondria
Cell
membrane
Rough ER
Phosphorus Potassium Plutonium
glucose
glucose
glucose
waste
waste
waste
correct
correct
Hint: What does the
Hint: What does the
Phospho…cmon! Phospho…cmon!
Back Home

Our cells need phospholipids, DNA, and
ATP. They each have phosphorus in them.
So where does the phosphorus come
from? Phosphorus come from rocks.
Rocks are solid lumps of minerals, and
some of those minerals are phosphorus.
So when rocks crumble and erode,
phosphorus is released from the rocks.
The weather causes rocks to crumble.
Wind, cold, and rain cause dust sized
fragments of rocks to chip off, thus
releasing phosphorus into the ground
Back Home

Make it Rain!
The weather causes
phosphorus to be released
from rocks. Click the cloud to
make it rain.
Small bits of phosphorus are
released into the ecosystem
due to the weather.
Click the cloud to make it stop
raining.
Now that there is phosphorus
in the soil, click on the land
organism that can absorb it
through their roots.
PPPPPP
Snails don’t
have roots.
Roots…
think roots
Back Home

The Producers
Of course! Plants simply
absorb the phosphorus
through their roots. Click on
the roots to proceed.
Now that plants have
phosphorus they can use it to
make their DNA, ATP, and
phospholipids.
Click on the herbivore (primary
consumer) in the diagram.P P
P
P
P
P
Decomposers
feed on the
dead. This
plant is alive.
Back Home

The Consumers
Of course! The snail is an
herbivore so it eats the plant.
This is how animals get the
phosphorus to make their
DNA, ATP, and phospholipids.
Phosphorus simply moves up
the food chain. Which
organism would likely eat
snails?
P
P
P
P
P
P
P
PP
Maybe
accidentally, but
cows are
herbivores too.
Wolves are
hunters. I don’t
think they would
hunt snails.
Back Home

Up the Food Chain
The snail eats the plant…
The frog eats the snail…
Which would likely eat the frog?
You got it. Phosphorus moves up the food chain.
P
P
I’m an
herbivore.
I’m an
herbivore.
P
Back Home

The Decomposers
This whole thing started with
crumbling rocks…remember?
Decomposers are organisms
such as mushrooms and
bacteria. They have DNA, ATP,
and phospholipids also, so that
means they need phosphorus
too.
Will decomposers feed on
dead plants?
You got it. Will they feed on
dead snails?
We’re almost done.
PP
P
P
P
P
P
P
P
yes no
P
yes no
Like any organism, decomposers
make waste. They release their
waste into the ecosystem. Some
of their waste even contains
phosphorus.
P
Examine the picture… if
decomposers release phosphorus
into the soil, which organism can
reuse the phosphorus?
The plants
The rocks
The snails
I hope you see why it’s
called the phosphorus
cycle.
Rocks aren’t
organisms
What do snails
eat?
Back Home

1. Which molecule does not contain phosphorus?
2. How does phosphorus get into the soil in the first place?
3. Where do herbivores get phosphorus from?
4. Where do carnivores get phosphorus from?
5. Where do decomposers get phosphorus from?
The Quiz
DNA ATP Carbohydrate Phospholipid
From rocks
From
decomposers
From
consumers
From
producers
From rocks
From
decomposers
From
consumers
From
producers
From rocks
From
decomposers
From
consumers
From
producers
From any
dead
organism
From
decomposers
only
From
consumers
only
From
producers
only
Back Home

The Human Factor
Sadly, human actions are disrupting the phosphorus cycle. Humans, like this farmer, routinely
add extra phosphorus to soil because phosphorus is a fertilizer. What do you think the extra
phosphorus does for the farmer’s crops?
P
P
P
P
P
PPPPPP
Kill weeds Kill bugs Stimulates growthNo. Weed killer
kills weeds.
No. Pesticides kill
bugs.
Yes, exactly!
So if phosphorus helps crops grow,
why is this bad?
Back Home

Why is this Bad?
The extra phosphorus is intended
to help crops grow better, but often
the phosphorus is washed away
into rivers, lakes, and ponds when
it rains.
P
P
P
P
PP
PThe extra phosphorus got washed
away and is collecting in this pond.
Since the phosphorus is a fertilizer, it
causes algae in the pond to grow at an
extreme rate. These extreme algae
growths are called “algal blooms.” As
the algae eventually die, the decaying
process uses up the oxygen in the
pond, thus all the fish die. Once the
fish die, so does the rest of the
ecosystem.
Make it rainRain Rain Go Away
Back Home

Carbon Cycle
• Plants pull carbon dioxide (CO2) from the
atmosphere.
• Using sunlight with the CO2 they make
glucose.
• This process is photosynthesis.
• The carbon can be used by the plant (food)
and used to build the plant (cellulose).
• Also gives off CO2 from cellular respiration.

Animals Eat Plants
• When organisms eat plants, they take in the
carbon and some of it becomes part of their
own bodies.
• They generate CO2 from cellular
respiration(break down of glucose) and
exhale this CO2 into the atmosphere.
Carbon Cycle

Animals Eat Animals
• When organisms eat animals, they take in
the carbon and some of it becomes part of
their own bodies.
• They generate CO2 from cellular respiration
(break down of glucose) and exhale this CO2
into the atmosphere.
Carbon Cycle

Plants and Animal Die
• When plants and animals die, most of their
bodies are decomposed and carbon atoms are
returned to the atmosphere.(CO2)
• Some are not decomposed fully and end up as
deposits underground (oil, coal, etc.= fossil
fuels=Carbon)
Carbon Cycle

Carbon Slowly Returns to Atmosphere
• Carbon in rocks and underground deposits is
released very slowly into the atmosphere.
• This process takes many years.
Carbon Cycle

Carbon in Oceans
• Additional carbon is stored in the ocean.
• CO2 passes into the water from the atmosphere.
• Plants & phytoplankton use for photosynthesis.
• Many animals pull carbon from water to use in
shells, etc.
• Animals die and carbon substances are deposited
at the bottom of the ocean.
• Oceans contain earth’s largest store of carbon.
Carbon Cycle

Burning wood and Fossil Fuels
• Releases carbon compounds in air, water, and
soil
• * one gallon of gas burned in a car=19lbs of
CO2 (Who Killed the Electric Car, 2004)
Carbon Cycle

Image obtained from http://www.agnr.umd.edu/users/agron/nutrient/Factshee/sulfur/Sulfur.html
Sulfur Cycle

Methods of preserving microbial culture

Agar Slant Cultures:
All microbiology laboratories preserve micro-organisms on agar
slant.
The slants are incubated for 24hr or more and are then stored in a
refrigerator.
 These cultures are periodically transferred to fresh media.
Agar Slant Culture Covered with Oil (Parafin Method):
The agar slants are inoculated and incubated until good growth
appears. They are then covered with sterile mineral oil to a depth of 1
cm above the tip of slant surface.
Transfers are made by removing a loop full of the growth, touching the
loop to the glass surface to drain off excess oil, inoculating a fresh
medium and then preserving the initial stock culture.
This is a simple and most economical method of preserving bacteria
and fungi where they remain viable for several years at room
temperature.
The layer of paraffin prevents dehydration of the medium and by
ensuring an aerobic condition, the microorganism remain in dormant
state.

Saline Suspension:
Sodium chloride in high concentration is frequently an inhibitor of
bacterial growth.
Bacteria are suspended in 1% salt solution (sub lethal
concentration in screw cap tubes to prevent evaporation).
The tubes are stored at room temperature.
Whenever needed the transfer is made on agar slant.
Preservation at Very Low Temperature:
The organisms are suspended in nutrient broth containing 15%
glycerol. The suspension is frozen and stored at -15°C to -30°C.
The availability of liquid nitrogen (temp -196°C) provides another
main preserving stock culture.
In this procedure culture are frozen with
a protective agent (glycerol or dimethane
sulphoxide) in sealed ampoules.
The frozen culture are kept in liquid nitrogen
refrigerator.

Preservation by Drying in Vacuum:
The organisms are dried over calcium chloride in vacuum and are
stored in the refrigerator.
Preservation by Freeze Drying (Lyophilisation):
Microbial suspension is placed in small vials. A thin film is frozen
over the inside surface of the vial by rotating it in mixture of dry ice
(solid carbon dioxide) and alcohol, or acetone at a temperature of
−78oC .The vials are immediately connected to a high vacuum line. This
dries the organism while still frozen. Finally, the ampules are sealed off
in a vacuum with small flame.
These culture can be stored for several years at 40°C.

Soil microbes break down organic matter (Decomposition)
Soil microbes help to recycle nutrients (Mineralization)
Soil microbes create humus
Soil microbes fix nitrogen
Soil microbes create soil structure
Soil organisms promote plant growth
Soil microbes control pests and diseases
Soil microbes can used for medicine and
to develop food products
Beneficial microorganisms in agriculture
Lactobacilli bacteria used in
yogurt and cheese making
Saccharomyces cerevisiae yeast
used in bread making and
alcohol production
The fungus Penicillium produces
the antibiotic Penicillin

Food spoilage
• (a). Growth and activity of microorganisms
Bacteria, yeasts and molds are microorganisms that cause food spoilage.
They produce various enzymes that decompose the various constituents of
food.
• (b). Enzyme activity:
Action of enzymes found inherently in plant or animal tissues start the
decomposition of various food components after death of plant or animal.
• (c). Chemical reactions:
These are reactions that are not catalysed by enzymes.,e.g. oxidation of fat
• (d). Vermin.
• Vermin includes weevils, ants, rats, cocroaches, mice, birds, larval stages of
some insects. Vermin are important due to:
(i) Aesthetic aspect of their presence (ii) Possible transmision of
pathogenic agents, (iii) Consumption of food.
• (e). Physical changes.
• These include those changes caused by freezing, burning, drying, pressure,
etc.

Sources of microorganisms in food
The primary sources of microorganisms in food include:
1. Soil and water
2. Plant and plant products
3. Food utensils
4. Intestinal tract of man and animals
5. Food handlers
6. Animal hides and skins
7. Air and dust

Methods of food preservation
Drying: Sun and wind are both used for
drying
Freezing:Keeping prepared food stuffs
in cold storages
Smoking :Smoke is antimicrobial and
antioxidant and most often meats and
fish are smoked.
Vacuum packing:Vacuum by making bags
and bottles airtight
Salting and Pickling:Salt kills and inhibits
growth of microorganisms at 20% of
concentration. There are various methods
of pickling like chemical pickling and
fermentation pickling.
Sugar:To preserve fruits. .
Lye :Sodium hydroxide turns food
alkaline and prevents bacterial growth.
Food preservation is known “as the science which deals with the process
of prevention of decay or spoilage of food thus allowing it to be stored in a
fit condition for future use”.
Food Preservation

Canning and bottling:Sealing cooked food in sterile bottles and cans
Jellying: Fruits are generally preserved as jelly.
Potting: Preserving meat by placing it in a pot and sealing it with a layer
of fat.
Jugging: Brine or wine is used to stew meat.
Burial in the ground: Used to preserve cabbages and root vegetables.
Pulsed Electric Field Processing :Pulses as strong electric field to process
cells.
Modified atmosphere:Preserves food by operating on the atmosphere
around it.
Controlled use of organism: is used on cheese, wine and beer as they are
preserved for a longer time.
High pressure food preservation is a method that presses foods inside a
vessel by exerting 70,000 pounds per square inch or more of pressure.
Modified Atmosphere Packaging extends the shelf life of fresh food
products.
Besides these there is Pasteurisation and Irradiation are also used.
Food Preservation

s:
Bio pesticides are certain types of pesticides derived from such
natural materials as animals, plants, bacteria, and certain minerals.
For example, canola oil and baking soda have pesticidal applications
and are considered bio pesticides.
Bio pesticides can be classified into these classes
 Microbial pesticides which consist of bacteria, entomopathogenic
fungi or viruses (and sometimes includes the metabolites that
bacteria or fungi produce). Entomopathogenic nematodes are also
often classed as microbial pesticides, even though they are multi-
cellular.
 Bio-derived chemicals. Four groups are in commercial
use: pyrethrum, rotenone, neem oil, and various essential oils are
naturally occurring substances that control (or monitor in the case
of pheromones) pests and microbial diseases.
 Plant-incorporated protectants (PIPs) have genetic material from
other species incorporated into their genetic material (i.e. GM
crops).
Biopesticide

 Advantages of using bio pesticides
 Bio pesticides are usually inherently less toxic than
conventional pesticides.
 Bio pesticides generally affect only the target pest and closely
related organisms, in contrast to broad spectrum,
conventional pesticides that may affect organisms as different
as birds, insects and mammals.
 Bio pesticides often are effective in very small quantities and
often decompose quickly, resulting in lower exposures and
largely avoiding the pollution problems caused by
conventional pesticides.
Biopesticide

Composting
• Composting is the process of producing compost through
aerobic decomposition of biodegradable organic matter.
• Compost produced at the end of the process can be used in
farming and gardening to improve soil quality.
Type of composting
• Active (hot) composting
– ~55oC
– Higher temperature kill most pathogens
– Regularly stirring ensure aeration
– Faster (take weeks)
• Passive (cold) composting
– ~30oC
– Much slower (may take months)
– May develop anaerobic condition, releasing odor and
greenhouse gas (e.g. methane)

Advantages of composting
Reduction of the amount of waste
Lower costs than incineration
Recycling of humus and nutrients into the soil
Protecting and improving the microbiological diversity and
quality of cultivated soils
Beneficial role of compost microorganisms in crop protection,
in as much as they compete with plant pathogens,
Beneficial role of compost microorganisms in bioremediation
(biodegradation of toxic compounds and pollutants).
Composting

Fermentation
• The fermentation industry is composed of five major bio-ingredient
categories.
• They are:
- Proteins & amino acids - Organic acids - Antibiotics.
- Enzymes - Vitamins & hormones.
 Fermentation industry is driven by:
- The cost and availability of feed-stocks.
- The efficiency of industrial microorganism.
- Fermentation condition and optimization.
- Down stream process and end-product
recovery efficiency.
- Fermentation by-product utilization.
- Utility consumption and labor cost.

Industrial microorganisms
• Microbial screening.
- Wild strains.
• Microbial yield improvement
- Mutation.
- Recombinant DNA.
- Genetically engineered.
• Microbial selection.
• Industrial microorganism
161
93 C
43 C
21 C
4 C
Fermentation

Types of fermentation
Solid State fermentation (SSF).
Liquid State fermentation (LSF) Surface culture & submerged
culture
163
Fermentation

Microbiology

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Ähnlich wie Microbiology

Ähnlich wie Microbiology (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Microbiology