BT211 Iso & Iden. Microorg.

8/13/2019 BT211 Iso & Iden. Microorg.

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Isolation and Identification of

Microorganisms


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Microbiology is a specialized area of biologythat deals with microorganisms that include bacteria,

fungi, viruses, protozoaand someparasitic worms.

Industrial microbiology associates with the commercialexploitation of microbes for the benefit of mankind.

These microbial products may have direct or indirectimpact on the economics, environment and socialparameters of the society.

Microorganisms are used to create a wide variety ofproducts and to assist in maintaining and improving theenvironment


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Microbes have wide scope in different areas.

Some of them are; Starter cultures in commercial food and beverage

production.

Products of alcoholic fermentation.

Production of Enzymes and other industrial products.

Production of Alternative fuels.

Production of Pharmaceuticals, like antimicrobials,

recombinant hormones, and other cell regulators. Pesticides and agricultural products

Biosensors and bioreporters.


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Sr. No. PRODUCT SITE

1 Thermophiles Hot spring, thermophilic

vents, compost

2 Alkalophiles High salinity soils and wells

3 Acidophiles Pine growing sites, fruits

4 Osmophiles Seas and oceans

5 Yeast Wine yards6 Phosphate solubilizers Agricultural soil,

rhizosphere

7 Protease producers Dairy industry, meat

processing units.8 Enzymes like cellulase,

pectinase, xylanase etc.

Agricultural soil, paper and

pulp industry, waste

disposal area of fruit juice

plants, grain market.

9 Biogas (methane) producers Gober-gas plants, effluentcollection sites.


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Consists of only a single type of organism.

Rarely exist in nature. Naturally exist as mixed

cultures.

Pure cultures must be obtained artificially

Pure Culture


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Isolation

Microorganisms occur in huge numbers.

*Isolation of single species (pure culture) is done by :

Streak plate method

Pour plate method

* Based on diluting sample out to a point where

a single cell will give rise to a single colony


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Plate Pouring


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Streak Plate(Quadrant Streak)


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Streak Plate Isolation Principle Colony on media, one kind of microbe, pure culture

An original inoculum containing a mixture of bacteria

is spread into 4 quadrants on solid media.

The goal is to reduce the number of bacteria in eachsubsequent quadrant.


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Pour Plate


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Growing a Pure Culture

To grow microorganisms:Nutrients must be supplied in the

culture medium(Agar is the solidifying material used in solid media. It is anextract of seaweed that melts at 100oC and solidifies atabout 42oC)

A suitable environment must beprovided


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IncubationAllow organisms to grow under the optimal

conditions Temperature, with or without oxygen etc.


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After isolation of bacteria, it is important to identify

the specified bacteria.

Identification is mostly done with the help of

following characteristics

1) Morphology,

2) Selective and diagnostic media,

3) Cultural characteristics,

4) Additional recognized biochemical tests,

5) Profile of microbial stains, and

6) Rapid identification methods.


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1) Morphology :- Science dealing with the structures and forms of organisms.

It exclusively trusts confidently upon a number of factors,

such as shape, length and breadth, ends of organism, bodyarrangement,motility, formsspores, capsul etc.

2) Selective and diagnostic media :- It specifically favour the growth ofparticular

microorganisms.

Eg. MacConkeysagar medium for E. coli.

Differential media, Enrichment media, and Characteristic

media are types of this media.


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3) Additional recognized biochemical tests :-

These tests are extensively used for identificationpurpose. These tests are,

Carbohydrate (Sugar) Fermentation,

Fermentation end products

Hydrolysis reactions

Oxidation reactions

Litmus Milk,

Indole Production, Methyl Red Test [MR-Test],

Voges-Proskauer Test [VP-Test],

Citrate Utilization, etc.


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4) Profile of microbial stains :- Microbes are extremely small in size, hence to visualise

them,staining is done, in which either cell interior or exterior

part stains in colour. Different Staining technique includes, Gram staining, Differential

staining, Capsule staining ; Endospore staining ; Flagellar

staining.

Microscopic study: Gram + bacilli, Gram - bacilli


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5) Cultural characteristics :- Based upon a broad spectrum of intensive and conclusive

research carried out during the past few decade

These characteristics are, Shape, Size, Elevation Margins,

Surface, Edges ,Colour , Structure, Consistency, etc.


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6) Rapid identification methods :- These includes advanced techniques like SEM(Scanning

electron microscope), TEM (Transmission electron

microscope)

Scanning electron microscope: tremendous surface

detail

Transmission electron microscopevery high

magnification (100,000 X)

TransmissionScanning


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BT211 Iso & Iden. Microorg.

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