Microbes In Human Welfaregps


Microbes


Microbes In Household Products


Microbes In Industrial Products


Microbes In Sewage Treatment


Microbes In Production Of Biogas


Microbes As
Biocontrol

Agents


Microbes As
Biofertilisers



1. Microbes are microscopic organisms (invisible to
naked eye)



2. They are present everywhere on earth
-

in soil, water,
air, in our bodies, plants and even at the most extreme
locations such as hot water geysers and poles.



3. Microbes are diverse, they can be
-

protozoa,
bacteria, fungi, viruses,
viroids
,
prions

etc.



4. Microbes are thought to be the main disease causing
agents, but they can be helpful to human beings in
many ways. We will see how in

subsequent

slides.

Escherichia coli

Lactobacillus

Azatobacter

Methanobactarium


1.
Production of curd from milk


a. Microbes such as Lactobacillus and a group called Lactic
Acid Bacteria(LAB) convert milk to curd by producing acids
which partially digest and coagulate milk

proteins.



b. A small amount of curd (starter or
inoculum
) which is
added to milk contains millions of bacteria which multiply
under suitable conditions and thus converting it to curd.



c. This process increases the nutritional value of milk by
increasing vitamin B12 , it also checks disease causing
organisms in our stomach.



2
.

Fermentation



a
.

The

fermentation

of

dough

is

due

to

bacteria

and

its

puffed

appearance

is

due

to

the

production

of

CO
2

during

fermentation
.


b
.

Toddy,

an

alcoholic

drink

is

made

from

Fermentation

of

palm

sap
.


c
.

A

yeast,

Saccharomyces

cerevisiae

(baker's

yeast)

is

used

for

fermenting

bread

dough
.


d
.

Cheese

is

also

a

product

of

fermentation

and/or

ripening,

and

different

varieties

of

cheese

are

due

to

different

microbes

used

for

fermenting
.


e
.

The

holes

in

cheese

are

due

to

large

CO
2

production

by


the

bacteria
.


Saccharomyces

cerevisiae

as seen under DIC (Differential
Interference

Contrast)
microscope.

The large holes in

Swiss

cheese
are due to huge amount of CO
2

released during fermentation by
P
ropionibacterium

shermanii


1. Beverages


2. Antibiotics


3. Organic acids


4. Enzymes


5.

Bio
-
active

molecules



1.
Beverages


a. When juices and malted cereals are fermented they get
converted to ethanol.


b. Brewer's yeast (
Saccharomyces

cerevisiae
) is commonly
used for fermentation.


c. Drinks with versatile
colour

and
flavour

are produced
depending upon the raw material and nature of processing
used


d. Classification of beverages


(
i
) Whisky, Rum and Brandy are distilled beverages.


(ii) Wine and beer are not distilled.



2
.

Antibiotics


a
.
The

term

means

'against

life'

with

reference

to

disease

causing

organisms
.



b
.

The

first

antibiotic

penicillin

was

discovered

by

Alexander

Fleming
.


c
.

Penicillin

is

obtained

from

a

fungus

Penicillium

notatum
.


d
.

These

are

used

in

treatment

of

a

number

of

diseases

such

as,

diptheria
,

leprosy,

whooping

cough,

plague

etc
.



3. Organic acids


a. Various organic acids are produced with the help of
microbes. The below lists the organic acids and name of
the microbe employed in producing it
-


Organic Acids

Microbe

1.
Citric Acid

2.
Acetic Acid

3.
Butyric acid

4.
Lactic

Acid

5.
Ethanol

1.
Aspergillus

niger

(fungus)

2.
Acetobacter

aceti

(bacterium)

3.
Clostridium
butylicum

(bacterium)

4.
Lactobacillus
(bacterium)

5.
Saccharomyces

cerevisie

(yeast)


4
.

Enzymes

produced

with

the

help

of

microbes

are
-


i
.
Lipases

(lipid

dissolving,

produced

by

Candida

lipolytica
)


ii
.

Proteases


iii
.

Pectinase


a
.

Lipases

are

added

in

detergents

for

removing

oily

stains


b
.

Pectinases

and

proteases

are

used

to

clear

fruit

juices

during

bottling
.


c
.

Streptokinase

is

produced

by

Streptococcus
.

It

is

modified

by

genetic

engineering

and

used

as

'clot

buster‘

for

dissolving

blood

clots

of

patients

after

myocardial

infarction
.



5. Bioactive molecules



a.
Cyclosporin

A


i
. A fungus
Trichoderma

Polysporum

produces it.


ii. It has
immuno

suppresive

properties so it is used as an
immuno
-
supressive

agent during organ transplantation.


b.
Statins


i
. These are the products of fermentation activity of yeast,
Monascus

purpureus
.


ii. It inhibits cholesterol synthesis, so used for
lowering

blood

cholesterol level.


Beer, a
product of
fermentation

Antibiotics

Acetic
acid, the
main
component
of
Vineger

Cholesterol lowering
tablets(statins)


Need for sewage treatment
-


1. The municipal waste water(sewage) contains large amount
of organic waste and microbes.


2. This can invite diseases and epidemic when this water
meets community water bodies like lake pond and rivers.


3. To check this the sewage is made less polluting by passing it
through sewage treatment plants(STPs)


This involves two steps
-


i
. Primary Treatment


ii. Secondary Treatment



1. Primary treatment


a. It is a physical process, it uses
sedimentation and
filtration
to filter small and large particles.


b. First the sewage is passed through mesh screens of
small pore sizes to remove floating objects like
polythene.


c. The grit is removed by

sedimentation

by passing
sewage into grit chamber.


d. Then it is kept in settling tanks, where the suspended
materials settle down to form the primary sludge.


e. The remaining fluid is taken for secondary treatment.



2. Secondary treatment


a. It is a biological process by heterotrophic bacteria present in the sewage.


b. The primary effluent is aerated in aeration tanks.


c. This causes rapid growth of aerobic bacteria, which then as '
flocs
'
consume the organic matter to
reduce the Biochemical Oxygen
Demand

(BOD).


d. After this the effluent is passed to settling tanks where these '
flocs
' get
sedimented
. (Activated Sludge).


e. A part of this sludge is pumped back to aeration tanks for further use.


f. This sludge is pumped to anaerobic sludge digesters, where anaerobic
bacteria form gases like methane CO
2

and H
2
S.


g. After this the effluent is released into water bodies like streams and rivers.


Microorganisms In Sewage Treatment


1.
Biogas


a. Biogas consists of methane(60%) and CO2(40%)


b. Produced by
Methanobacterium

by acting on
cellulosic compounds, these are found in rumen of
cattle and anaerobic sludge of sewage.


c. Cattle dung contains both cellulosic as well as
methanogens

so it's used for biogas production.


d. It is a popular method for meeting energy
requirements of rural households, and also helps in
reducing precious firewood.



2.
The steps involved in the production of biogas
-


a. The biogas plant consists of a 10
-
15 feet deep
concrete tank in which the slurry of dung is fed.


b. A floating cover is kept over the slurry which keeps on
rising as the gas is produced in the tank by microbial
activity.


c. An outlet connected to a pipe is present in the
biogas plant for the removal of biogas and supplying it
to required places.


d. The spent slurry is removed through another outlet
which can be used as a
fertiliser
.


A typical biogas plant.

A biogas plant in Tamil Nadu.


1.
Biological control
is defined as the reduction of pest


populations

by natural enemies and typically involves
an active human role.


2. For Example
-


a. The spores of
Bacillus
thuringiensis

(Bt) are toxic to
certain larvae, but not harmful for others.


b. The fungus
trichoderma

is being used for fighting
plant diseases.


c.
Baculoviruses

are the pathogens used for attacking
harmful insects and arthropods, they belong to genus
Nucleopolyhedrovirus
.



1. The use of
biofertilsers

instead of chemical ones has been
known to keep the soils fertility intact for longer durations. They
are organisms like bacteria, fungi and
cyanobacteria
, that
enrich the soil.


2. a. Bacteria
-

Rhizobium
,
Azospirilium
,
Azatobacter

fix
atmospheric nitrogen and enrich nitrogen content of soil.


b. Fungi
-
They form symbiotic relation with roots of plants
eg
.
mycorrhiza
. It absorbs phosphorous and passes it to plant, also
it shows resistance to pathogens and salinity.


c.
Cyanobacteria

-

They are autotrophic microbes which can
fix atmospheric nitrogen, for
eg
.
Anabaena,
Nostoc
,
Oscillatoria
. They are important
biofertilisers

in paddy
fileds
.