KANCHAN SHEKHAWAT XII SCIENCE (2024 – 20

PM SHREE JAWAHAR NAVODAYA VIDYALAYA, KAJRA

BIOLOGY PROJECT FILE

SESSION :- 2024-25
PROJECT –
REPORTED BY – KANCHAN SHEKHAWAT
CLASS – 12th SCIENCE , ROLL NO. –
REPORTED TO – MR.SUNIL YADAV
( P.G.T. BIOLOGY )

SIGN. OF EXTERNAL EXAMINER SIGN. OF PRINCIPAL

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KANCHAN SHEKHAWAT XII SCIENCE (2024 – 20

CERTIFICATE
Type your text

This is to certify that KANCHAN SHEKHAWAT of class XIIScience roll no. has satisfactorily completed her
Biology investigatory project on Microbes in human welfare under the guidance of Mr. SUNIL YADAV

as prescribed by the course during the academic year 2024 – 2025.

INTERNAL EXAMINER’S SIGN.

EXTERNAL EXAMINER’S SIGN. PRINCIPAL

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ACKNOWLEDGEMENT

I would like to sincerely and profusely thank my biology teacher Mr. (PGT BIOLOGY)
and our lab attendant for their able guidance and support in completing my project.

I would like to extend my gratitude to the principal MR. SUNIL YADAV for providing me with all the
Facility that was required.

SIGN. OF CANDIDATE

CONTENTS
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KANCHAN SHEKHAWAT XII SCIENCE (2024 – 20

1. Introduction …………………………………………………………………………………… 5

 Microbiology
 What are Microbes ?
 Kinds of Microbes

2. Microbes in Households ………………………………………………………………………… 8

3. Microbes as Biocontrol agents …………………………………………………………………... 10

4. Microbes as Fertilizers …………………………………………………………………………….. 12

5. Bibliography …………………………………………………………………………………………. 14

INTRODUCTION
 MICROBIOLOGY :

The branch of science which deals with the study of microorganisms It further numerous sub

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disciplines including virology, bacteriology , parasitology, mycology etc.

➢ WHAT ARE MICROBES ?

Microbes are tiny living things that are found all around us . They may or may not be
visible to the naked eye. Microorganisms are very diverse; they include bacteria, fungi, algae,
and protozoa; microscopic plants (green algae); and animals such as rotifers and planarians.

Microorganisms live in all parts of the biosphere even where no other life form can exist, such
as in deep water, including soil, hot springs, on the ocean floor, high in the atmosphere and
deep inside rocks within the Earth's crust.

Microorganisms are critical to nutrient recycling in ecosystems as they act as decomposers. As

some microorganisms can fix nitrogen, they are a vital part of the nitrogen cycle, airborne
microbes may play a role in precipitation and weather. Microbes are also exploited by people
in biotechnology, both in traditional food and beverage preparation, and in modern
technologies based on genetic engineering.

Pathogenic microbes are harmful, since they invade and grow within organisms , causing
diseases that kill humans, plants & animals.

➢ KINDS OF MICROBES
There are different types of microbe present on our earth, they are :-

1. Algae

Algae are a diverse group of eukaryotic, non-vascular thallophytes, autotrophic,

Chlorophyl containing organisms capable of producing oxygen through
photosynthesis.

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2. Bacteria
Bacteria are very tiny single-cell microbes that can live in all environmental
conditions.

3. Protozoa
Protozoa are microscopic unicellular eukaryotes, either free-living or parasitic.

4. Virus

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A virus is a submicroscopic infectious microbe that replicates only inside the living
cell of an organism.

5. Fungi
Fungi are eukaryotic, multicellular organisms that include Yeasts , moulds, etc

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MICROBES IN HOUSEHOLDS
Microbes and their products are used everyday in the making of cheese, curd, dough, bread, vinegar
and other foods in everyday life. Lactic acid bacteria (LAB), also known as Lactobacillus acidophilus,
Lactobacillus lactis, and Streptococcus lactis, are probiotic bacteria that inhibit the growth of harmful
bacteria in the stomach and other regions of the digestive tract .

Curd: Microorganisms such as Lactobacillus and others commonly called Lactic Acid Bacteria (LAB)
grow in milk and convert it into curd. During growth, the Lactic acid bacteria produce acids that
coagulate and partially digest the milk proteins called casein.

Paneer: Paneer (cottage cheese) is a fresh cheese common in South Asia ,especially in India. It is
made by curdling milk with lemon juice, vinegar and other edible acids. Large holes in Swiss cheese is
due to the production of a large amount of carbon-di-oxide by the bacterium Propionibacterium
shermanii.

Idli and Dosa: The dough which is used for making dosa and idli is the fermented preparation of rice
and black gram (Urad dal).
1. The dough is allowed to ferment overnight for 10–1210–12 hours.
2. The lactic acid bacteria from Leuconostoc and Streptococcus species bring about fermentation.
Several other genera, like Bacillus,Candida, and Saccharomyces, are also used in this process.
3. During fermentation, CO2 is evolved, which causes doughing of the raw material. The bubbles
of CO2 trapped in gluten makes the idli puffy.

Yoghurt: Yoghurt provides protein and calcium, and it may enhance healthy gut bacteria.
1. Yoghurt is produced by curdling milk with the help of Streptococcus thermophilus and Lactobacillus
bulgaricus, Streptococcus lactis, etc.
2. Initially, milk is heated to 80 –90 C80 –90 C for half an hour. It is cooled to 40 –43 C and mixed with
an inoculum containing the Streptococcus thermophilus bacteria.
3. After four hours, yoghurt becomes ready. It has an original flavour of lactic acid and acetaldehyde.
4. Since it is already acidic (pH3.7–4.3),(pH3.7–4.3), yoghurt is often sweetened and flavoured with
fruits.

Bread: Bread is made from wheat flour.

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1. The dough that is used for making bread is fermented by using themicrobe Saccharomyces
cerevisiae which is commonly called Baker’s Yeast .

Cheese: Different varieties of cheese are known for their characteristic texture, flavour and taste. The
specificity comes from the microbe that is used in it. For example, the large holes in ‘Swiss cheese’ are
due to the production of a large amount of CO2CO2 by a bacterium named Propionibacterium
shermanii. In contrast, the ‘Roquefort cheese’ are ripened by growing a specific fungus on them, which
gives them a specific flavour.

Pickles: Pickles prepared by lactic acid bacteria (LAB) fermentation have a unique flavour and beneficial
health effects. These LABs are slightly different as they can comfortably tolerate higher concentrations
of salt and sugar. Lactobacillus plantarum, L. brevis, Leuconostoc mesenteroids and pediococcus
cervisiae are used in making pickles.

MICROBES AS BIOCONTROL AGENTS

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➢WHAT IS BIOCONTROL?

The natural method of eliminating and controlling the insects, pests and other disease-causing agents
using their natural, biological enemies is called biocontrol or biological control. The agents which are
employed for this are called biocontrol agents. Microbes are one of them. Biocontrol works on the
principle of predation. It is much reliable and healthier than killing insects and pest using insecticides
and pesticides.
Thus, this prevents soil pollution and health issues related to insecticide poisoning, etc.

➢BIOCONTROL AGENTS

Biocontrol agents are an integral part of organic farming. In organic farming, farmers believe in
mutualism. In other words, organic farmers keep a balance of useful and harmful agents within the
system. The chemicals used for eradicating pest and parasite might not be always successful and also
harm useful agents too. Instead, farmers used biocontrol agents which predate the insects and pests
that cause diseases to crops.

➢MICROBIAL BIOCONTROL AGENTS

Ladybird and dragonflies are two common insects which are employed to eradicate aphids and
mosquitoes respectively. Other than insects, microbes are also used as biocontrol agents. These
microbes include bacteria, fungi, viruses, and protozoans. Microbes act as biocontrol agents in three
ways, either they cause diseases in the pests or compete with them or kill them.

Biotechnology has extended widely and has developed many biocontrol agents. For example, Bacillus
thuringiensis which is often referred to as Bt is a microbial biocontrol agent. Spraying the solution of Bt
made of spores on plants will kill the butterfly caterpillars. The spores that are ingested release toxins in
the guts of the larvae and kill them. Biotechnology has developed disease-resistant and pest-resistant
plants by injecting the toxic genes of B. thuringiensis into plants. For e.g. Bt cotton. Fungus-like
Trichoderma and baculoviruses of genus Nucleopolyhedrovirus are some other microbial biocontrol
agents. These agents are specific in nature; this along with the cost limits their use.

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MICROBES AS FERTILIZERS
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The Biofertilizer is a substance containing Microorganisms that help with Soil Fertility, and this helps in
making the plant grow in a healthy way. This also helps in increasing the stream of vital nutrients in
trees and plants. The Biofertilizers impart living organisms like mycorrhizal fungi, blue-green algae plus
other types of bacterial Biofertilizers. The role of the bacteria as a form of Biofertilizers helps with the
restoring of Soil’s organic matter, and the regulation is done by natural.

There are various types of Microorganisms that act as the biofertilizers.

Each of the types comes with its own exclusive capability and function.
There are mainly 6 types of the Microbes that are used as the
Biofertilizers. These Microbes are Rhizobia, Azotobacter , Azospirillum, Blue-green algae, Azolla, and
Phosphate-solubilizing Microorganisms

➢ IMPORTANCE OF BIOFERTILIZERS

 The Biofertilizer Microbes are utilized for fixing the nutrients within the Soil, especially related

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to the Insufficient Nitrogen.

 The Biofertilizer is the living organism and it helps in converting the composite organic material
into the simple compounds. This makes it easier for the plants or trees to take them.

 The usage of Microorganisms as fertilizers helps in enhancing the growth of plants enormously

and it also gives the richness back to the Soil.

 Instead of controlling the growth, the Microorganisms help in advancing the process of growth

within plants especially related to the growth in new seed.

The Microorganisms as the Biofertilizers are incredibly cost-effective in comparison to synthetic
fertilizers. You also have the option of growing it in your farm and then use it for the healthy growth of
the crops. The micro-organisms also tend to provide good quality nourishment for the plants in
comparison to the chemical fertilizers.

BIBLOGRAPHY
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NCERT class 12 book of biology

MTP NCERT FINGERTIPS BIOLOGY book

 www.google.com

 https://en.wikipedia.org

 https://www.slideshare.com

 https://scribd.com

 www.pinterest.in

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