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An Overview of Scope of Microbiology
Lesson: An Overview of Scope of Microbiology
Lesson Developer: Riti Mann
College/Department: National Institute of Malaria
Research
Institute of Lifelong Learning, University of Delhi
1
An Overview of Scope of Microbiology
Table of Contents
Lesson: An Overview of Scope of Microbiology

Introduction

Microbiology as a subject and its various branches

Pure Microbiology

Applied Microbiology
o Microbes in Environment
o Microbes in Human health
o Industrial Applications of Microbes
o Microbes in Food and Dairy
o Biotechnological uses of Microbes

Emerging areas of Microbiology
o
Exomicrobiology
o
Nanomicrobiology

Microbiology: Scope and Future Perspectives

Summary

Exercise

Glossary

References
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An Overview of Scope of Microbiology
Introduction
Microbiology as a term exhibits Greek roots: ‘micros’-small, ‘bios’-life and ‘logia’-study,
so it refers to the study of small living organisms (microbes). The question is “why study
microbes when they are so small and simple organisms”? We have already deliberated on
the enormous diversity of microorganisms in preceding lessons. These microorganisms
influence our lives in both harmful and useful ways. On one hand they cause diseases, on
the other hand they find immense applications in almost all areas of science; whether it
be chemical studies, space studies, industrial production and many more. They also
affect the environment in which they grow. Thus, Microbiology as a subject provides
ample opportunity to know microorganisms and their role in various fields.
Microbes provide a number of advantages to be used in industries. They are small in size
with high surface area, have short generation time, display the capability of carrying out
tremendous variety of reactions and most importantly they can adapt to an array of
environments. All these properties help in improving yields, thereby making the process
commercially viable.
This lesson attempts to explore the scope of Microbiology by discussing various pure and
applied branches of microbiology and analyzing role of microbes in various fields like
industries, medicine, food and dairy. It also mentions the roles that microbes play in an
environment, highlighting on their role in treatment of sewage wastewater. Applied
aspects of microbiology such as exomicrobiology and the use of microbes in
biotechnology have also been encompassed briefly.
Microbiology as a Subject and its Various Branches
Microbiology being the study of all those organisms that can’t be seen with naked eye
includes viruses, bacteria, many algae, fungi, protozoa etc. Based on their characteristic
features, these organisms can be classified as prokaryotes and eukaryotes. However,
viruses are neither prokaryotes nor eukaryotes. They are considered as acellular
microorganisms as they exhibit living as well as non-living characteristics.
Microorganisms vary in size from that of a single atom up to 1mm size (Figure 1).
Figure 1: Comparison of the Sizes of Prokaryotes with respect to Eukaryotes and
Biomolecules.
Source: http://en.wikipedia.org/wiki/Bacteria#mediaviewer/File:Relative_scale.svg (CC)
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An Overview of Scope of Microbiology
Fascinating facts about microbes


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One single teaspoon of soil contains 1 billion bacteria, 120,000 fungi and 25,000
algae.
There are 10 times more bacteria in the average human’s digestive system than there
are cells in the entire body.
Microbes generate at least half the oxygen we breathe.
Most microbes do not cause disease - less than 5% do.
Botox is made from a deadly bacterial toxin, which is used in very small doses to
remove wrinkles.
The largest organism in the world when measured by area is the Honey Mushroom
fungus. It covers a whopping 8.9km2 of a national forest in the USA.
Source: http://www.microbiologyonline.org.uk/students/fascinating-facts
Additional information
The group, led by microbiologist William B. Whitman, estimates the number of bacteria
on earth to be five million trillion trillion-that's a five with 30 zeroes after it.
Source: http://www.sciencedaily.com/releases/1998/08/980825080732.htm
Some important facts about microorganisms are that:




The presence of microbes is ubiquitous. They exist on all natural surfaces: soil, water,
body of all organisms etc. Some can live in extreme environments like hot springs,
frozen sea, etc.
Most of the microbes are harmless to us. Instead, they help us by secreting various
economically useful metabolites.
They keep the biosphere running by performing biodegradation and cycles of carbon,
nitrogen, oxygen, sulfur, etc.
Microorganisms can also harm humans. They cause diseases in plants as well as
animals and food spoilage.
It means that microbiology should not only include the structural diversity and
classification of microbes but also must encompass all aspects of microbial life i.e. their
form, structure, reproduction, physiology, metabolism, distribution, occurrence and
economic importance. The knowledge on all these aspects of microbes has been
accumulating since last century and has become so vast that microbiological studies have
been broadly divided into pure and applied science branches (Figure 2). Some of the pure
/fundamental branches include Bacteriology, Virology, Mycology, Phycology etc. The
applied branches include Food, Industrial, Medical etc.
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An Overview of Scope of Microbiology
Figure 2: Pure and Applied Branches of Microbiology.
Source: Author
Besides these, some other branches are also developing, however, they are still in
infancy. Microbiology has closer relationship with Genetics and Biochemistry as it
provides convenient use of microbes as genetic models. It is also a major contributor to
the fields of recombinant DNA technology and genetic engineering. From this knowledge
it can easily be concluded that Microbiology has immense scope due to its ability to
control all critical points of fields, like Medical, Industrial, Agriculture, Pharmaceutical,
Dairy, Genetics, Nanotechnology etc.
Now let’s discuss briefly about these branches of microbiology, focusing on the
importance of members from each group.
Pure Microbiology
Virology refers to the study of viruses, very small infectious agents that can only be
observed under electron microscope.
Some interesting facts about viruses are:
 Their approximate size ranges between 20 to 300 nm, i.e. they can pass through the
pores of filters used for excluding bacteria (usual pore size-2μm).
 Viruses are obligate intracellular parasites. They require live cells to grow and cannot
be cultured in artificial media.
 Viruses use host machinery for generation of energy and protein synthesis.
 Viruses have either DNA or RNA as their genetic material, but no virus has both of
these.
Name the largest known virus?

French researchers have recently reported a virus that is 1μm long. They named this
virus as ‘Pandoravirus’ (In greek mythology, Pandora’s box is a large jar which
contained all the evils of the world).

Before the discovery of Pandoravirus, Mimivirus (Mimicking microbe) was the largest
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An Overview of Scope of Microbiology
known virus with a size of 400-500 nm. Mimivirus was accidently discovered in
amoeba Acanthamoeba polyphaga.
An infectious virus is termed as ‘virion’.
Baltimore classification has placed viruses into seven groups, as described in Figure 3.
Figure 3: Baltimore Classification
Source:
http://upload.wikimedia.org/wikipedia/commons/a/a5/VirusBaltimoreClassification.svg
(CC)
Bacteriophages (Bacteria eaters)/ Bacterial viruses/ Phages are the viruses that are used
widely in genetic research.
Bacteriology is the branch of microbiology that deals with another group of
microorganisms- Bacteria. Morphologically, bacterial cells are spherical (cocci), rod like
(Bacilli) or helical. These basic shapes of bacteria are usually found arranged in groups:
pairs, clusters, trichomes and filaments. All these shapes and arrangements of bacteria
have been illustrated in Figure 4.
Figure 4: Morphologies and Arrangements of Bacterial Cells.
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An Overview of Scope of Microbiology
Source:
http://upload.wikimedia.org/wikipedia/commons/6/69/Bacterial_morphology_diagram.sv
g (CC)
Phycology is the study of algae (singular-alga), which are microorganisms containing
chlorophyll and are photosynthetic. They occur in almost all habitats. They exist in varied
forms, ranging from small, single-celled (flagellates) to complex multicellular (kelps).
Algae have great economic importance. Agar, which is used as a solidifying agent in
microbiological media, is derived from algal cell wall. Carrageenan (used as stabilizer in
foods) and alginic acid (used for providing smooth consistency to ice cream) are some of
the other products of economic value obtained from algal cell walls. Some species of
algae are also used as food. For instance, the red algae Porphyra is used as a food in
Japan named as “nori”.
Mycology is the study of fungi. Fungi are a group of eukaryotic organisms that do not
have chlorophyll and are heterotrophic. They are of immense value to industrialists, as
they are responsible for producing a large number of commercially valuable products.
They play significant role in brewing of beer, wine making, production of antibiotics and
many more. The most common example is the use of yeast Saccharomyces in
fermentation of beer and wine.
Fungi are also identified as the causative agents of diseases in plants, humans and other
animals. For instance, Candida albicans causes candidiasis of skin and mucous
membranes.
Protozoology is science of protozoa (Greek protos and zoon means ‘first animal’), the
eukaryotic protists. They are usually unicellular and free living. Protozoa that eat bacteria
help to maintain ecological balance in aquatic environments as well as in wetlands.
However, some protozoa may be parasitic. Out of the four species of Plasmodium
protozoa (Plasmodium falciparum, P. vivax, P. ovale and P. malariae), the causative
agents of malaria in humans are P. falciparum and P. vivax.
Immunology deals with immune system and the response generated by it against
various disease causing microorganisms.
Microbial Physiology provides insight into the physiology of microorganisms with
respect to their nutritional requirements, growth conditions, and metabolic reactions.
Applied Microbiology
Microbes in Environment
Environment includes everything (biotic as well as abiotic components) that surrounds an
organism. There is a hierarchy of living systems within the biosphere, which is described
in Figure 5.
Organism
Population
Community
Ecosystem
Landscape
Biome
Biosphere
Figure 5: Hierarchy of Living Systems.
Source: Author
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An Overview of Scope of Microbiology
Similar microorganisms form assemblies known as ‘populations’. The population of
microorganisms when interacts with another population of different kind of
microorganisms is termed as ‘community’. A.G Tansley proposed the term ‘ecosystem’ in
1935. It is a functional unit comprising of organisms interacting among themselves, with
other organisms and with their physical environment. These interactions are studied
either under Microbial Ecology or under Environmental Microbiology (Figure 6). The
benefits of studying these two subjects can be illustrated by a few examples given below.
Figure 6: Microbial Ecology and Environmental Microbiology
Source: Author
Image Source:
http://commons.wikimedia.org/wiki/File:Ananda_Mohan_Chakrabarty_-_Kolkata_200911-08_3037.JPG (CC)
Additional Information


Thomas Brock discovered the bacterium Thermus aquaticus. Thermus aquaticus is
known all over the world as source of Taq polymerase, an enzyme used in
Polymerase Chain Reaction (PCR).
Ananda Mohan Chakrabarty is an Indian American microbiologist, who developed the
genetically engineered bacteria Pseudomonas putida. This bacterium is capable of
degrading a number of hydrocarbons and therefore, finds application in
bioremediation. A patent has also been granted to Prof. Chakrabarty for this
genetically engineered bacterium.
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An Overview of Scope of Microbiology
Microbes while interacting with each other, with other higher organisms and with their
environment; play an array of beneficial roles. They contribute to the functioning of
ecosystems by maintaining ecological balance. Microorganisms are involved in
biogeochemical cycling; they degrade and solubilize many useful minerals that are
otherwise not available to organisms.
Microorganisms attach to various surfaces and form biofilms. These consist of layers of
microbial cells adherent to the surfaces. Biofilms are important to study, as they relate to
almost all areas of microbiology. The most appropriate example is the formation of dental
caries as a result of biofilm formation by microorganisms like Lactobacilli and
Streptococci.
Pathogenic
microorganisms
like
Pseudomonas
aeruginosa
and
Staphylococcus epidermidis form biofilms. This confers them resistance to antibiotics,
thereby, making their treatments even more difficult.
There is a direct consequence of the formation of microbial film/biofilm on the surface of
water distribution pipes. It causes severe economic losses. This process of corrosion
carried out by the microbial population is called as ‘Biocorrosion’. The buried pipes are
usually coated to prevent contact between the metal surface, water and soil microbial
population; thereby preventing biocorrosion caused by microbial films.
Microorganisms play both beneficial and detrimental roles in the mining and mineral
processing of metals. The metabolic activities and capabilities of the microbes are
exploited to improve the recovery of metals and petroleum from the environment. Sulfur
oxidizing Thiobacilli are employed commercially in the process of bioleaching- recovery of
copper, uranium and other metals.
Microbes are also useful in the process of waste management. Waste obtained from
various sources like household, industries, etc. can either be solid waste or liquid waste.
Solid waste is managed by methods like Composting, Landfills, Incineration, etc.
Liquid waste or wastewater is treated in a sequential manner, starting with
Primary/Physical treatment, followed by Secondary/Biological treatment and at last
Tertiary treatment. In primary treatment, particulate material is removed by passing the
wastewater through grids of decreasing pore size, as shown in Figure 7. Primary
treatment also includes the process of settling in tanks (Figure 8), which further removes
the particulate material.
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An Overview of Scope of Microbiology
Figure 7: Schematic Representation of the Process in which Wastewater is Passed
through a Series of Grids of Decreasing Pore Size. This process separates out the
particulate material.
Source: Author
Figure 8: Settling Tank.
Source: http://en.wikipedia.org/wiki/Sewage_treatment
Secondary or Biological treatment involves use of microorganisms. After this treatment,
BOD (Biochemical Oxygen Demand) is reduced by 90-95% as compared to the original
BOD of wastewater. Microorganisms commonly used are filamentous bacteria such as
Sphaerotilus and Thiothrix.
Secondary treatment of liquid waste can be treated either aerobically or anaerobically.
Figure 9 lists different types of aerobic and anaerobic treatment methods that are
available. The important features of all these treatment methods along with their pictures
are given in Table 1.
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An Overview of Scope of Microbiology
Figure 9: Types of Liquid Waste Treatment.
Source: Author
Table 1. Different Types of Aerobic and Anaerobic Treatment Methods for Liquid Waste
Source: Author
Aerobic Treatment Methods
(A) Aerobic Tanks
These are open tanks in which proper
aeration is provided for activating the
natural microflora of sewage water.
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An Overview of Scope of Microbiology
(B) Trickling Filter
Consists of a fixed bed of rocks over
which sewage flows downward and causes
a layer of microbial slime (biofilm) to
grow, which ultimately covers the whole
bed.
A boom type sprinkler continuously
revolving over the bed distributes sewage.
Microbes present in the biofilm then act on
the trickling wastewater.
(C) Biological Disks
Consists of a series of closely spaced,
parallel discs made up of plastic. These
discs are mounted on a rotating shaft
which is supported just above the surface
of the waste water.
Microorganisms grow on the surface of the
discs where biological degradation of the
wastewater pollutants takes place.
Anaerobic Treatment Methods
(D) Septic Tank
Initially the sedimentation of suspended
organic
matter
occurs,
followed
by
decomposition of organic matter by
anaerobic or facultative anaerobes.
(E) Imhoff Tank
It is a two-chamber system, which permits
the development of better effluent.
Decomposition takes place by anaerobic
and facultative anaerobic microorganisms.
(F) Anaerobic Digester
Complex organic matter degradation occurs
releasing carbon dioxide and hydrogen.
This carbon dioxide is then reduced to
methane, which can be used for energy
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An Overview of Scope of Microbiology
generation.
Final product is a mixture of methane
(70%) and carbon dioxide (30%).
Source of images:
(A) http://en.wikipedia.org/wiki/Aerated_lagoon - mediaviewer(CC)
(B) http://commons.wikimedia.org/wiki/File:Trickling_filter_bed_2_w.JPG (CC)
(C) http://commons.wikimedia.org/wiki/File:ACAI_DEPURACION__EDAR_BIODISCOS.jpg (CC)
(D) http://en.wikipedia.org/wiki/Septic_tank - mediaviewer(CC)
(E) http://en.wikipedia.org/wiki/Imhoff_tank#mediaviewer (CC)
(F) http://en.wikipedia.org/wiki/Anaerobic_digestion#mediaviewer (CC)
Tertiary treatment removes mineral nutrients. This involves the process of disinfection,
which is done by chlorination or by ozonation. Chlorination is an inexpensive method,
whereas ozonation is a more effective method as compared to chlorination.
Aerobiology is also an applied aspect of microbiology that deals with the study of
microorganisms suspended in air. Other than the living microorganisms, it also includes
the study of various air-borne microbiological agents such as endospores, fungal spores,
etc.
Atmosphere provides a very hostile environment for microorganisms and therefore the
number of microbes found in air is small as compared to that in soil or water. Some
microorganisms that have been reported to be present in atmosphere include:
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Fungi- Alternaria, Aspergillus, Fusarium, Penicillium
Bacteria- Corynebacterium, Flavobacterium
Algae- Diatoms
Some yeasts have also been reported to be present in atmosphere.
Additional Information
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Atmospheric particles, such as mists or dust, of size within μm range are referred to
as ‘Bioaerosols’.
Clouds, which provide even harsher conditions to microbes, have also shown the
presence of bacteria.
Infact, clouds serve as a means by which microbes are transported to long distances.
Detailed information about the significance of microbes in environment is available in the
lesson ‘Role of Microbes in Environment’.
Microbes in Human Health
Microbes in humans cause a number of diseases. Examples of important diseases are
tuberculosis (Mycobacterium tuberculosis), leishmaniasis (Leishmania sp.), AIDS (HIVHuman Immunodeficiency Virus), etc.
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An Overview of Scope of Microbiology
Microbes are a good source of antibiotics, which for a long time have been the mainstay
of our defense against many infections. Preparing an antibiotic using chemical synthesis
processes is extremely expensive, so microorganisms are used by pharmaceutical
industries for their production.
In addition to being a good source of antibiotics, microbes are also important
contributors in other aspects of health sciences. For instance, viruses are being used as
tools in gene therapy; they help in easy delivery of gene to the target cell.
Industrial Applications of Microbes
The entire industrial process of manufacturing and marketing a product can broadly be
divided
into
the
following
major
steps:
Preparation/Upstream
processing,
Production/Fermentation, Extraction, Downstream processing that also includes
marketing. Microbes are used immensely at the step of fermentation (Table 2). They may
have to be manipulated genetically in order to improve product yield.
Table 2: Microbes Commonly Used in Industries
Source: Author
Industry
Enzymes production
Citric acid production
Microorganisms used
Asperillus oryzae (Amylase),
Saccharomyces cerevisiae (Invertase),
Bacillus subtilis (Amylase), Trichoderma
reesei (Cellulase), Rhizomucor pusilley
(Proteases)
Aspergillus niger
Alcohol production
Saccharomyces cerevisiae, Candida
shehatae, Zymomonas mobilis
Lactic acid production
Lactobacillus lactis, Leuconostoc
mesenteroides
Antibiotic production
Penicillium sp. (β-lactam drugs),
Streptomyces nodasus (Amphotericin B)
Amino acid production
Corynebacterium glutamicum (Glutamate)
Microbes in Food and Dairy
Microbes are used for production of a variety of food products and sometimes they are
themselves used as food (SCP). Some of the dairy products along with the
microorganisms used in their production are given in Table 3. Unknowingly, we ingest
various microbes on daily basis. For instance, the bread we take daily is prepared by
using yeast culture and the curd that we eat is full of Lactobacilli. So without even
realizing, we are continuously interacting with microbes.
Table 3: List of Some Dairy and non-dairy Products and the Microorganisms Involved in
Their Production
Source: Author
Dairy Product
Microorganisms Involved
Dahi
Lactococcus lactis, Streptococcus thermophiles
Acidophilus milk
Lactobacillus acidophilus
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An Overview of Scope of Microbiology
Cultured buttermilk
Lactococcus lactis, Leuconostoc citrinovorum
Bulgarian buttermilk
Lactococcus bulgaricus
Yoghurt
Lactococcus delbrueckii, Streptococcus thermophiles
Cheese
Cheddar cheese
Lactococcus lactis
Cottage cheese
Lactococcus lactis, Leuconostoc spp.
Swiss cheese
Streptococcus thermophiles, Propionibacterium shermanii
Camembert cheese
Penicillium camembertii, Lactococcus lactis
Roquefort cheese
Penicillium roquefortii, Lactococcus lactis
Non-dairy Product
Microorganisms Involved
Kefir
Lactococcus lactis, Lactobacillus brevis
Kumiss
Lactobacillus bulgaricus, Torula sp.
Pickels
Lactobacillus plantarum, Pediococcus
cerevisiae
Pediococcus halophilus, Pediococcus soyae
Soy sauce
Besides their role in production of foods, microorganisms are themselves used as dietary
supplements in the form of SCP (Single Cell Protein). C.L. Wilson coined this term in
1966. SCP refers to the microbial biomass or proteins obtained from them, which are
used as food and feed additives. Microorganisms commonly used as SCP are: algae
(Chlorella, Spirulina), yeasts (Candida tropicalis, Candida utilis), bacteria (Cellulomonas,
Nocardia), filamentous fungi (Morchella deliciosa, Fusarium monoliforme).
Further detailed information about the various applications of microbes in food industry is
available in the lesson’ Application of Micro-organisms in Food and Dairy Industry’.
Biotechnological Uses of Microbes
Microorganisms, especially bacteria and yeast, serve as factories for propagation of
plasmids that have foreign gene (from other organism) cloned into them. Apart from
this, genetic engineering has facilitated the process of manipulating the genetic
information of a microbe, in such a way that microbes can now be used for production of
industrially and pharmaceutically valuable products at high scale. The first and the best
use of a microbe for synthesis of recombinant product is that of HUMULIN. Humulin is the
recombinant human insulin produced by cloning the human insulin gene into a laboratory
strain of E. coli.
To list out few biotechnological applications of microorganisms:

Gene therapy: Treatment in which a normal or genetically altered gene is inserted
into the cells so as to compensate for the missing or nonfunctional gene. For
example, for treating SCID (Severe combined immunodeficiency disease), viral
vectors mainly phages are used as tools for delivering normal or altered gene into the
cells (Figure 10).
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An Overview of Scope of Microbiology
Figure 10: A Newspaper Clipping Showing Use of Virus in Gene Therapy for Curing
Blindness.
Source: Times of India dated Dec. 10, 2014

Microbes as Biopesticides: Transgenic plants expressing B. thuringiensis (Bt) toxin
gene have been developed, in which Bt gene has been spliced into plant genes using
Ti plasmid of Agrobacterium tumifaciens. These include Bt-corn, Bt-potato, Bt-cotton
and Bt-brinjal.

Microbes in Bioremediation: Genetically engineered bacterium- Pseudomonas
putida, is capable of degrading a number of hydrocarbons and is used for removing
oil spills.

Microorganisms in Fermentation: Recombinant microbes with foreign gene cloned
or with overexpression of their indigenous genes are currently being used at large
scale in industries. For example; for production of antibiotics like streptomycin,
enzyme production and many more. Mutant strains of microorganisms displaying high
levels of expression are also being used for overproduction of industrially valuable
products.

Microbial Sensors: The most common and natural biosensors are lichens, which do
not grow or their growth is retarded due to the presence of pollutants in environment.
Microbial biosensors have also been applied in detection of Biochemical Oxygen
Demand (BOD).
Emerging Areas of Microbiology
Exomicrobiology
Exomicrobiology (Figure 11) is a newly emerging field that includes the study of
microorganisms in space and space like environment (exposing microorganisms to very
harsh environment, like that in space).
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An Overview of Scope of Microbiology
Astrobiology
SPACE
MICROBIOLOGY
Exobiology/
Extra- terrestrial microbiology
Cosmology
Figure 10: Space Microbiology- The study of microbes in outer space or space like
conditions.
Source: Author
Microbiological studies are carried out directly in the space environment or by using
facilities that simulate the conditions of outer space.
Microorganisms serve as the most appropriate living creatures, whose studies provide
valuable information about the effect of space environment on living systems. These
studies further open the doors for possibility of life in outer space.
Nanomicrobiology
Nanomicrobiology is study of microbiological samples by applying atomic force
microscopy (AFM). It provides three-dimensional image of the cells and membranes at
nanoscale which helps understand changes in microbial surfaces on interaction with
drugs and other chemicals.
Something to Ponder about….
The field of microbiology has achieved its present status only after many and many novel
discoveries by innumerable scientists. But now the question arises- who should be called
as the ‘Father of Microbiology’?
This is an interesting debatable topic within the scientific community, that who should be
crowned as the Father of ever-expanding field of Microbiology. There are a few
highlighted candidates for this place:

Anton van Leeuwenhoek who invented the microscope and opened the world of
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An Overview of Scope of Microbiology



invisible microbes. Thus, he was the one who initiated the field of microbiology.
Some say that Robert Hook should be called as the Father of Microbiology, as he
reported the first microbiological observation of fruiting bodies of molds.
While in the viewpoint of some others, Louis Pasteur should be the Father of
Microbiology. He introduced the process of pasteurization, made significant
contributions to the beer fermentation process, disproved the theory of Spontaneous
generation and most importantly introduced the sterilization flask. Culture plates that
we commonly use in our laboratories for keeping the media sterile, are based on the
same principle as was introduced by Louis Pasteur in his flask.
Robert Koch, because of his pioneering work in the field of bacteriology, can also be
crowned as the Father of Microbiology.
Who do you think should be the Father of Microbiology????
And the debate continues ……
Microbiology: Scope and Future Perspectives
(What to do being graduates in this field????)
Throughout the lesson we discussed about the pure and applied branches of
microbiology. In this entire discussion, the applied aspects of microbiology have been
dealt focusing mainly on the use of microorganisms in diverse areas. But this discussion
is incomplete for a student who has recently started in this field and wants to know the
future possibilities. For him/her, the main motto of reading this lesson is to know the
areas towards which he/she can shape his/her career. Here comes the need of describing
the scope in detail. Lets first have a look at below mentioned websites on career
opportunities in Microbiology to get basic idea of what can be done.
https://www.youtube.com/watch?v=nElhiCyXJZA
http://timesofindia.indiatimes.com/home/education/news/Micro-world-Careeropportunities-in-microbiology/articleshow/20624271.cms
http://www.biotechnologyforums.com/thread-1676.html
What All can be Done?
Microbes find applications in many a number of places and perform tasks that are just
impossible to carry out without them. Even if the tasks are possible, they are not
economically feasible. For instance, use of microorganisms for production of antibiotics.
Antibiotics can also be manufactured by chemical processes (by chemists) but the cost is
extremely high. So this is one area (pharmaceuticals) where microbiologists can work.
They are the ones who not only can apply microorganisms in production but also can
even genetically modify the microorganisms for making the procedure economically
viable.
Not just pharmaceuticals, microorganisms are used in production of numerous food
products. Microorganisms provide special flavor and texture to these food products. For
example; baking, brewing, cheese preparation and many more. You all must have heard
about the newly available health drink in Indian market, Yakult. This is a fermented milk
product containing bacterium Lactobacillus casei strain Shirota.
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An Overview of Scope of Microbiology
Figure 11: Yakult
Source: Author
For further information on Yakult, refer: http://www.yakult.co.in/
Similarly, there are so many other food products prepared using microorganisms.
Microbiologists find these kinds of industries really appealing to work with.
Did you know??
The number of microorganisms known to be present on earth is far below their actual
number. We are unable to identify these unknown microorganisms because of a number
of reasons, few of them are:



Lack of machinery and technology
Inability to reach inaccessible/extreme areas
Difficulty in culturing microorganisms
There are a large number of microorganisms that cannot be cultured under laboratory
conditions. For studying these microbes, a recent concept termed ‘Metagenomics’ has
been introduced. It is a study involving isolation of genomic contents of all the members
of a community and their analyses using various techniques like DGGE (Denaturing
Gradient Gel Electrophoresis), thereby, bypassing the need for culturing the microbes.
Microbiologists are also an integral part of ever expanding enzymes, acids, and vitamins
producing industries. It is so common to manipulate microbes for their production and
further to scale up the process using modified strains.
Microbes, as we all know, play innumerable beneficial roles but some microorganisms are
also known to be harmful. They actually cause diseases in plants as well as in animals.
For controlling these diseases, rapid and cheap diagnostic methods should be known in
addition to their treatment options. Microbiologists play key roles in developing both of
these.
https://docs.google.com/file/d/0B828qi2N1qG-S3FpMnhLcXN6UHM/edit?usp=drive_web
Microbiology is such an inter-related subject that a person experienced in this field is well
equipped to carry out research in any area of his/her interest. To name a few; structural,
molecular, biochemical, immunological, genomic and scale up studies. There are
innumerable numbers of institutions, universities and organizations that are working on
various aspects of microbiology. For details about the research institutes in India, refer to
the link: http://www.indiabioscience.org/jobs/research-institutes. However, the list may
not be considered complete.
There are so many newly emerging areas where microbiologists genuinely have a place.
Lets say the area of epidemiological studies, which is so urgent in present day scenario
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An Overview of Scope of Microbiology
where everyday new pathogens are emerging and we actually don’t know their origin or
the mode by which they spread.
In short, it can be said that ‘Microbiology as a word has everything to say about it but
even then the definition is incomplete without excavating its horizons’.
Summary
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Microbiology encompasses the study of prokaryotes (Bacteria, archaea, etc.),
eukaryotes (protozoans) and acellular organisms-viruses.
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Because of the immense roles that microbes play, the broad field of microbiology is
divided into pure and applied branches. The applied aspects of Microbiology include
Environmental Microbiology, Industrial Microbiology and so on.
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Aeromicrobiology is the branch that deals with the study of various air-borne
pathogens. This field finds relevance while studying hospital-acquired infections,
which are usually air-borne.
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Exomicrobiology and Nanomicrobiology are newly emerging areas of Microbiology.
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Microbes in environment are involved in many a number of jobs. They keep the
ecosystem running by maintaining ecological balance. They are involved in the
process of degradation and mineral cycling, solubilizing mineral nutrients and making
them available to other organisms.
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Various methods have been developed for treatment of sewage water. They are
broadly divided into aerobic and anaerobic methods. Aerobic methods include Aerobic
tanks, Trickling filter and Rotating Biological Disks. Anaerobic methods include Septic
tank, Imhoff tank and Anaerobic digester.
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Microbes are causative agents of a variety of diseases in humans, but are also the
source of life saving antibiotics.
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Industrial production of many products is not economically viable without the use of
microorganisms. Therefore, since a long time, industries have been using microbes
for production of antibiotics, amino acids, beer and many more products.
Exercise
Short answer questions
1. Define the following terms:
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Virology
Bacteriology
Phycology
Mycology
Protozoology
Aeromicrobiology
Exomicrobiology
Biocorossion
Humulin
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20
An Overview of Scope of Microbiology
2. Explain briefly the role of microbes in mineral recovery.
3. Give an example of microorganism used for production of the following:
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Amylase enzyme
Citric acid
Lactic acid
Amphotericin B
Dahi
Acidophilus milk
Yoghurt
Swiss cheese
Roquefort cheese
Kefir
Kumiss
Soysauce
SCP
4. Write a short note on ‘SCP’.
5. Write briefly about Exomicrobiology.
6. Differentiate between Microbial Ecology and Environmental Microbiology.
Long answer questions
1. Explain the harmful effects of biofilm formation.
2. Explain the process of Secondary sewage treatment, mentioning about its different
methods.
Fill in the blanks
1. Viruses are considered as ______ microorganisms as they exhibit both living and
non-living characteristics.
2. The presence of microbes is ______.
3. Viruses are ______ intracellular parasites.
4. ______ classification has placed viruses into seven groups.
5. The red algae ______ is used as a food in Japan.
6. The causative agent of malaria is ______.
Answers
1.
2.
3.
4.
5.
6.
acellular
ubiquitous
obligate
Baltimore
Porphyra
Plasmodium protozoa
Glossary
Antibiotics: Antibiotics are agents that either kill or retard the growth of
microorganisms. For bacteria, they are termed as Bacteriostatic (hampers the growth) or
Bactericidal (kills the bacteria).
Bioleaching: The process of extraction of an element from its ore by the use of
microorganisms.
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An Overview of Scope of Microbiology
Biosphere: The living creatures on earth and their environment when combined, is
termed as biosphere.
Candidiasis: Fungal infection caused by Candida sp. Infection is usually caused on skin
and sometimes in vagina.
Cosmology: The science that answers the questions of origin of universe, its evolution
and predicts about its future.
Downstream Processing: The industrial process after the actual fermentation that
includes purification, packaging and marketing.
Facultative Anaerobes: Microorganisms that by nature are aerobic but can also survive
by generation of energy if oxygen is absent.
Gene Therapy: It is an approach in which genetic material of an organism is targeted so
as to treat a disease.
Upstream Processing: The steps prior to start of an industrial fermentation process
that includes media optimization, conditions standardization etc.
References
Books
 Ronald M. Atlas and Richard Bartha; Microbial EcologyApplications, Fourth Edition (2009); Pearson Education.
Fundamentals
and
 Prescott, Harley and Klein; Microbiology, Seventh Edition (2008); Mc Graw Hill
Education.
 Michael J. Pelczar, E.C.S. Chan, Noel R. Krieg; Microbiology, Fifth Edition (2007); Tata
Mc Graw Hill Edition.
Web links
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http://www.youtube.com/watch?v=72gwwyz2ZWg
http://www.nature.com/scitable/topicpage/discovery-of-the-giant-mimivirus14402410
http://www.sciencedirect.com/science/article/pii/S095656631000607X
https://www.educationnest.com/digistore/products/6329-microbiology/169917emerging-scope-of-microbiologist/966
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