BIOLOGY

PROJECT
KENDRIYA VIDYALAYA CME
PUNE – 31

CLASS-12TH SCIENCE

INVESTIGATORY PROJECT

TOPIC – MICROBES IN HUMAN

WELFARE
TEACHER – MRS.PREMLATA

NAME- NIKITA SINGH

YEAR – 2021-2022
 CERTIFICA
TE
This is to Certify that the project reported here has been carried out
independently by Miss. Nikita Singh of 12th – Science studying in Kendriya
Vidyalaya CME Pune – 31 under the guidance of Mrs. Premlata during the
academic year 2021 – 2022 on the topic Microbes in Human Welfare
of Biology subject. She has taken proper care and has shown utmost sincerity in
the completion of the project. I certify that this project is up to expectations in
this pandemic situation and it has been done as per the guidelines issued by
CBSE.
 ACKNOWLEDGEMENT
I would like to express my special thanks of gratitude to my biology teacher

Mrs. Premlata as well as our principal mam Mrs. Sangeeta Gutain who gave

 me the golden opportunity to do this wonderful project on the topic “Microbes in

Human Welfare”, which also helped me in doing a lot of research,

and I came to know about many new things. I am thankful to them. Secondly,

I would also like to thank my parents and friends who helped me a lot in

finalizing this project within the limited time frame 

INTRODUCTION
What are microbes?
A microorganism or a microbe is a microscopic organism that comprises either a
single cell {unicellular}, cell clusters, or multicellular relatively complex
organisms.
The study of microorganisms is called microbiology. A subject that began with
Anton Van’s discovery of microorganisms in 1675, using a microscope of his own
design.
Microorganisms are very diverse. They include bacteria, fungi, algae and
protozoan. microscopic plants {green algae}, and animals such as rotifers and
planarias. Some microbiologists also include viruses, but other considered that
these are non-living.
Most microorganisms are unicellular {single celled}, but this is not universal,
since some multicellular organisms are microscopic, while some unicellular
protists are bacteria like Thiomargarita, Namibiensis, are macroscopic and are
visible to naked eyes

Namibiensis
Microorganisms live in all parts of biosphere where there is liquid water,
including soil, hot springs, on the ocean floor, high in the atmosphere and deep
inside rocks within the earths crust

Microorganisms are critical to nutrient recycling in ecosystem as they act as

decomposers
As some microorganisms can fix nitrogen, they are a vital part of nitrogen cycle,
and recent studies indicate that airborne microbes may play a role in
precipitation and weather

SOYABEEN ROOT
{NITROGEN FIXING BATERIA}
Microbes are also exploited by people in biotechnology, both in traditional food
and beverage preparation, and in modern technologies based on genetic
engineering.

However, pathogenic microbes are harmful since they invade and grow within
other organisms, causing disease that kill humans, other animals and plants. but
they have a lot of uses too.

A title description
Microorganisms are vital to humans and the environment, as they participate in
the Earth’s elements cycles such as the carbon cycle and nitrogen cycle, as well as
fulfilling other vital roles in virtually all ecosystems, such as recycling and other
organisms dead remains and waste products through decomposition. Microbes
also have an important place in higher – order multicellular organisms as
symbionts Many blame the failure of biosphere 2 on any improper balance of
microbes

Small introduction
The branch of biology which deals with the study of microorganism are called as
“Microbiology”. the biosphere i.e., the biotic and abiotic component has a variety
of microorganisms that exhibit beneficial activities. They include small algae,
fungi, bacteria, protozoans, mycoplasmas and related organisms. A large number
of microbes help human civilization through their useful activities. These
activities are either of domestic, industrial or commercial importance. It has
several applied branches such as medical microbiology, food microbiology,
industrial microbiology, etc
 MICROBES IN
HOUSEHOLD
PRODUCTION

Uses of microorganisms are used in brewing, winemaking, backing, pickling and

other food making processes. They are also used to control the fermentation
process in the production of cultured dairy products such as yogurt and cheese.
The cultures also provide flavour and aroma, and inhibit undesirable organisms

Fermentation in food processing typically is the conversion of carbohydrates to

alcohols and carbon dioxide or organic acids using yeasts, bacteria, or a
combination there of, under anaerobic conditions. Fermentation in simple terms
is the chemical conversation of sugars into ethanol. The science of fermentation is
also known as zymology, or zymurgy. Fermentation usually implies that the
action of microorganisms is desirable, and the process is used to produce alcoholic
beverages such as wine, beer, and cider.
Fermentation is also employed in the leavening of bread {CO2 produced by yeast
activity}, and for preservation techniques to produce lactic acid in sour foods such
as sauerkraut, kimchi, yogurt, vinegar etc in pickling foods.

A number of microbes are involved in their production through the process of

fermentation. The use of microbes in food production is almost as old as human
civilization. Traditionally a number of microbes from the surrounding
environment are being used in production of several indigenous fermented foods.
A few examples are given below. Idli, dhokla, jalebi are common Indian
delicacies. The dough prepared is allowed to ferment for couple of days
1} MICROBES IN FOOD PREPARATION
The dough for dhokla is prepared by mixing grain flour (besan) with butter milk.
The lactobacilli bring about the fermentation process. Many species of bacteria
and yeast are useful in making idli and dosa. The bubbles trapped in glutein make
idlies puffy. The microorganisms like species of Bacillus, Candida and
Saccharomyces are involved in this process. Many lactobacilli are involved in the
preparation of jalebie, nan, etc.

YOGHURT BACTERIA

2} WINE MAKING PROCESS

The process of winemaking involves numerous stages starting with the grapes
being harvested, taken into a winery and then prepared for fermentation. At this
stage, red wine is created during the fermentation of the pulp (or "must") and
skins of the red or black grapes, which gives the wine its colour. White wine, on
the other hand, does not include the grape skins in the fermentation process; only
the juices are extracted. To start primary fermentation, a process that typically
takes between one to two weeks, yeast is added which converts the sugars in the
grape juice into alcohol and carbon dioxide, which then evaporates into the
atmosphere.

The produced liquid, which is known as "free wine," is then pumped into tanks
and the skins are pressed in order to extract the remaining wine and juice. This
wine, known as the "press wine," can be added to the free wine to bring more
character and longevity to the wine. Secondary fermentation is the next step,
which is the bacterial fermentation involving the conversion of malic acid to lactic
acid. This decreases the amount of acid in the wine and softens the taste. The wine
can then be transferred to oak barrels for maturation, with further adjustments
to taste and colour being made prior to filtering and bottling.

3} CHEESE MAKING PROCESS

Milk is often pasteurized to destroy pathogenic microorganisms and to eliminate
spoilage and effects induced by bacteria. The milk is then inoculated with
fermenting microorganisms and rennet, which promote curdling.
The fermenting microorganisms carry out the anaerobic conversion of lactose to
lactic. In the presence of lactic acid, rennet, or both, the milk protein casein
clumps together and precipitates out of solution; this is the process known as
curdling, or coagulation. Coagulated casein assumes a solid or gel like structure
(the curd), which traps most of the fat, bacteria, calcium, phosphate, and other
particulates. The remaining liquid (the whey) contains water, proteins resistant to
acidic and enzymatic denaturation (e.g., antibodies), carbohydrates (lactose), and
minerals.

Enzymes released by the bacterial cells also influence flavour development during
ripening. The curd is then gently heated, causing it to shrink. The degree of
shrinkage determines the moisture content and the final consistency of the cheese.
Whey is removed by draining or dipping.
Most cheese is ripened for varying amounts of time in order to bring about the
chemical changes necessary for transforming fresh curd into a distinctive aged
cheese. The ripening of cheese is influenced by the interaction of bacteria,
enzymes, and physical conditions in the curing room. The speed of the reactions is
determined by temperature and humidity conditions in the room as well as by the
moisture content of the cheese.

4} MICROBES IN BIOGAS PRODUCTION

Definition – Biogas is an important solution to present energy crisis, especially in
rural areas. The gas produced by action of bacteria on biomass is called biogas.
Composition – Biogas comprises a mixture of methane, carbon dioxide, hydrogen
sulphide and ammonia. These gases are produced sulphide and ammonia. These
gases are produced during anaerobic digestion of organic wastes from plants and
animals
Microbes involved - A special category of bacteria, called Methanogens, is most
commonly involved in the production of biogas. These are obligatory anaerobes
and cause the decomposition of cellulosic materials presently abundantly in the
dung of animals to produce biogas. As cattle dung is abundantly available in rural
areas so the gobar gas plants are most common in rural areas. Methanogens are
also present in the rumen of the compound stomach of cud-chewing mammals
and activated sludge of sewage treatment plants. The most common methanogens
are methanobacterium
Biogas plant - Animals and plant wastes are easily degraded by anaerobic
microorganisms in the presence of water. In this process, gases, such as methane,
and carbon dioxide, hydrogen, hydrogen sulfide, etc., produced. This mixture of
gases is called biogas. It contains about 65% methane which is an excellent fuel. A
slurry of animal dung and water is put into the plant. The biogas produced is
drawn through pipes and supplied to the customers. In order to get a continuous
supply of biogas, the plants need to be regularly fed with waste biomass, human
excreta can also be added to this. At some places, domestic sewage is digested in
the large biogas plant
FIXED DOME TYPE BIOGAS PLANT

FLOATING GAS HOLDER TYPE BIOGAS PLANT

5} MICROBES AS THE SOURCE OF FOOD

Some microbes or their fruiting bodies are directly used as a source of food, rich
in protein. The term ‘SCP’ or single cell protein denotes dead and dried cells of
microbes like bacteria, algae, moulds and yeasts. They are obtained by growing
microbes of various groups on different substrates. These microbes include
bacteria like. Bacillus subtilis, fungi like, species of Candida and Saccharomyces
cerevisiae and algae such as species of Chlorella. Mushrooms and truffles are
directly used as food. They belong to basidiomycetes (fungi) and produce large
fleshy fruiting bodies which are edible. They are low calorie, sugar-free, fat-free
but rich in proteins, vitamins, minerals and amino acids.

Some common examples of edible mushrooms are-

i. White button mushroom {BIOLOGICAL NAME - Agaricus bisporus }

ii. Paddy straw mushroom {BIOLOGICAL NAME - Volvariella volvacea}
iii. Oyster mushroom {BIOLOGICAL NAME - Pleuratus florida}

SOME MUSHROOMS ARE NON- EDIBLE AS THEY ARE

POISNIOUS
e. g. toadstools.

WHITE BUTTON
MUSHROOM

TOADSTOOLS
6} MICROBES IN INDUSTRIAL PRODUCTION
Alcoholic beverages are the products of alcoholic fermentation of
specific substrates. They include liquors like wine, beer and whisky. The
use of microbes in making fermented beverages is known since about
700 B.C. to Egyptians, Romans and Greeks.

A number of strains of the’ yeast. Saccharomyces cerevisiae var.

ellipsoideus are used in industrial production of wine. Different flavours
of wine are obtained by using different fruit juices.

Beer is another alcoholic liquor obtained from fermented grains,

mostly barley. Suitable strains of S. cerevisiae are used for
fermentation. ‘It is produced through various steps like malting,
mashing and fermentation. It is allowed to stand for a few days. Then it
is clarified, carboxylated, filled in bottles, packed and marketed. Wine
and beer are produced without distillation. Whisky is obtained by
fermenting mixed’ grains of corn, wheat, bailey, etc. The product of
fermentation is then distilled.

7} ORGANIC ACID FERMENTATION

A number of organic acids are obtained by fermentation using various
microbes as given below

Organic acid Microbes used

i) Citric acid Aspergillus niger
ii) Gluconic acid Aspergillus niger
iii) Fumaric acid Rhizopus arrhizus
iv) Acetic acid Acetobacter aceti

8} USES IN WATER TREATMENT

Uses in water treatment Specially-cultured microbes are used in the biological
treatment of sewage and industrial waste effluent, a process known as
bioaugmentation. Bioaugmentation is the introduction of a group of natural
microbial strains or a genetically engineered variant to treat contaminated soil or
water. Usually, the steps involve studying the indigenous varieties present in the
location to determine if bio stimulation is possible. If the indigenous variety do not
have the metabolic capability to perform the remediation process, exogenous
varieties with such sophisticated pathways are introduced.

Lactobacillus Bacteria

Bioaugmentation is commonly used in municipal waste water treatment to restart

activated sludge bioreactors. Most cultures available contain a research based
consortium of Microbial cultures, containing all necessary microorganisms
(B.licheniformis, P.polymxa, Penicillium, Aspergillus sp, Arthrobacter, etc )
Whereas activated sludge systems are generally based on microorganisms like
bacteria, protozoa, nematodes, rotifers and fungi capable to degrade bio
degradable organic matter.
9} VITAMIN PRODUCTION
Vitamins are complex organic compounds required in very small quantities for
normal growth and development of the body. They include vitamins A. B, C, D, E
and K. They may be water soluble (vitamins B and C) or fat soluble (vitamins A,
D, B and K). All the vitamins are not produced in human body. Therefore, they
are to be consumed through food or tablets.
Vitamins are manufactured by fermentation technology using different microbial
sources as given below
Name of the vitamin Microbial source
i. Vitamin B2 Neurospora gossipii
Eremothecium ashbyi
ii. Vitamin B12 Pseudomonas denificans
iii. Vitamin C Aspergillus niger
10} ANTIBIOTIC PRODUCTION
Some secondary metabolites, products of fermentation, have therapeutie
importance arid are used in medical treatment. For example, penicillin and a
number of other antibiotics are used in control of infectious diseases.

Antibiotics are the substances produced in small amounts by certain microbes to

inhibit die growth of other microbes. They may be anti-fungal (fungistatic or
fungicidal) or anti-bacterial (bacteristatic or bactericidal) in nature.
The first antibiotic was discovered accidentally by the British physician Dr.
Alexander Fleming in 1929 when he was working with the pathogenic bacterium
Staphylococcus aureus. Since then, a number of antibiotics have been produced
and used therapeutically. Some common antibiotics and their microbial sources
are listed below.

Antibiotic produced Microbial source

1) Chloromycetin Streptomyces venezuelae
ii) Erythromycin Streptomyces erythreus
iii) Penicillin Penicillium chrysogenum
iv) Streptomycin Streptomyces griseus

Many deadly diseases such as plague, whooping cough, diphtheria and leprosy,
which Used to kill millions all over the world can be now controlled by antibiotics.
11} USES OF ENERGY
Uses in energy Microbes are used in fermentation to produce ethanol,and in
biogas reactors to produce methane. Scientists are researching the use of algae to
produce liquid fuels, and bacteria to convert various forms of agricultural and
urban waste into usable fuels. Ethanol fermentation, is a biological process in
which sugars such as glucose, fructose, and sucrose are converted into cellular
energy and thereby produce ethanol and carbon dioxide as metabolic waste
products. Because yeasts perform this conversion in the absence of oxygen,
ethanol fermentation is classified as anaerobic. Ethanol fermentation occurs in the
production of alcoholic beverages and ethanolfuel, and in the rising of bread
dough.
Cellulosic ethanol is a biofuel produced from wood, grasses, or non-edible parts of
plants . It is a type of biofuel produced from lignocellulose, a structural material
that comprises much of the mass of plants. Lignocellulose is composed mainly of
cellulose, hemicellulose and lignin. Corn stover, switchgrass, miscanthus,
woodchips and the by products of lawn and tree maintenance are some of the
more popular cellulosic materials for ethanol production. Production of ethanol
from lignocellulose has the advantage of abundant and diverse raw material
compared to sources like corn and cane sugars, but requires a greater amount of
processing to the sugar monomers available to the microorganisms that are
typically used to produced ethanol by fermentation
 CONCLUSION
Microbes are a very important component of life on earth. Not all microbes are
pathogenic. Many microbes are very useful to human beings. We use microbes
and microbially derived products almost every day. Microbes are essential in
processes like Wine making and Cheese making. Bacteria called lactic acid
bacteria (LAB) grow in milk to convert it into curd. The dough, which is used to
make bread, is fermented by yeast called Saccharomyces cerevisiae. Certain
dishes such as idli and dosa, are made from dough fermented by microbes.
Bacteria and fungi are used to impart particular texture, taste and flavour to
cheese.
Many microbes are used for commercial and industrial production of chemicals,
enzymes and other bioactive molecules. Antibiotics like penicillins produced by
useful microbes are used to kill disease-causing harmful microbes. For more than
a hundred years, microbes are being used to treat sewage (waste water) by the
process of activated sludge formation and this helps in recycling of water in
nature. Microorganisms are used in fermentation to produce ethanol, and in
biogas reactors to produce methane Methanogens produce methane (biogas) while
degrading plant waste. Biogas produced by microbes is used as a source of energy
in rural areas. It is clear from the diverse uses human beings have put microbes to
that they play an important role in the welfare of human society.