Detection and isolation of a microorganism from a natural environment like soil containing large number of microbial population is called as screening. It is very time consuming and expensive process.

1. SECONDARY SCREENING OF
INDUSTRIALY IMPORTANT
MICROORGANISMS
NAME: DHRUVI SUVAGIYA
CLASS:MSC SEM 3

2. WHAT IS SCREENING??
• SCREENING The procedure of isolation, detection , and
separation of microorganisms of our interest from a mixed
population by using highly selective procedures is
called screening.
• Microorganisms source environment (air , water, soil) food
(milk, cheese etc. )
• There are multiple ways to manipulate a microorganism in
order to increase maximum product yields.
• Introduction of mutations into an organism may be
accomplished by introducing them to mutagens.

3. WHY SCREENING REQUIRES??
• Micro-organisms play key roles in nutrient cycling,
biodegradation, climate change, food spoilage, the cause and
control of disease, and biotechnology. Bacteria are
economically important as these microorganisms are used by
humans for many purposes.
• The beneficial use of microorganisms includes the production
of traditional food like cheese &yogurt and in agriculture for
compost & fertilizers.Medicinally, microbes can be used for
creating antibiotics in order to treat antibiotics, as well as in
order to synthesize amino acids and organic solvents. can also
be used as a bio pesticide instead of using dangerous
chemicals.

4. WHAT ARE THE ABILITY OF ORGANISMS?
The organisms which are chosen for screening should be……
• It should be able to grow on relatively cheaper substrates.
• It should grow well in an ambient temperature preferably at
30-40°C. This reduces the cooling costs.
• It should yield high quantity of the end product.
• It should possess minimum reaction time with the equipment
used in a fermentation process.
• It should possess stable biochemical characteristics.
• It should yield only the desired substance without producing
undesirable substances.
• It should possess optimum growth rate so that it can be easily
cultivated on a large scale.

5. TYPES OF SREENING METHOD??

6. SECONDARY SCREENING??
• Primary screening helps in the detection and isolation of
microorganisms from the natural substrates that can be used
for industrial fermentations for the production of compounds
of human utility, but it cannot give the details of production
potential or yield of the organism. Such details can be
ascertained by further experimentation.
• This is known as secondary screening, which can provide
broad range of information pertaining to …
1. Ability or potentiality of the organism to produce metabolite
that can be used as an industrial organism.
2. The quality of the yield product.
3. The type of fermentation process that is able to perform.
4. Elimination of the contaminant.

7. Secondary screening will provides the information about
……..
• product is toxic or not.
• products are new
compound or not.
• yield potentialities of
various isolated
microorganisms.
• requirements of the
microorganism
• organism is genetically
stable or not.
• physical properties of the
product.
• The new organism should
be identified to the species
level.
• Should eliminate
contaminations.
• determine the economic
status of a fermentation
process undertaken by
employing newly isolated
microorganism.

8. Giant Colony Technique
• This technique is used for isolation and detection of those
antibiotics, which diffuse through solid medium. Species of
Streptomyces, is capable of producing antibiotics during
primary screening. The isolated Streptomyces culture is
inoculated into the central area of a sterilized petri plates
containing nutrient agar medium and are selected. The plates
are incubated until sufficient microbial growth takes place.
• Cultures of test organism, whose antibiotic sensitivity is to be
measured are streaked from the edges of plate’s up to but not
touching the growth of Streptomyces and are further incubated
to allow the growth of the test organisms. Then the distance
over which the growth of different test organisms is inhibited
by the antibiotic secreted Streptomyces is measured in
millimeters.

9. • The relative inhibition of growth of different test organisms by
the antibiotic is called inhibition spectrum. Those organisms
whose growth is inhibited to a considerable distance are
considered more sensitive to the antibiotic than those
organisms, which can grow close to the antibiotic. Such
species of Streptomyces, which have potentiality of inhibiting
microorganisms is preserved for further testing.

10. Filtration Method
• This method is employed for testing those antibiotics which
are poorly soluble in water or do not diffuse through the solid
medium. The Streptomyces is grown in a broth and its
mycelium is separated by filtration to get culture filtrate.
Various dilutions of antibiotic filtrates are prepared and added
to molten agar plating medium and allowed to solidify.

11. Liquid Medium Method
• This method is generally employed for further screening to
determine the exact amount of antibiotic produced by a
microorganism like Streptomyces.
• Erlenmeyer conical flasks containing highly nutritive medium
are inoculated with Streptomyces and incubated at room
temperature. They are also aerated by shaking continuously
and vigorously during incubation period to allow
Streptomyces to produce the antibiotic in an optimum quantity,

12. WHAT KIND OF ORGANISMS ISOLATES??
• Antibiotic producers
Cephalosporium acremonium
Penicillium griseofulvum
Bacillus subtilis
Bacillus polymyxa
Streptomyces nodosus
Streptomyces griseus
Micromonospora purpurea
• Organic acid producers
Aspergillus niger
Yarrowia lipolytica
Candida tropicalis
• Secondary metabolites producers

13. REFERRENCE
• https://www.biotechnologynotes.com/microorganisms/screening/
screening-of-microorganisms-primary-and-secondary-
techniques-industrial-
biotechnology/13697#:~:text=Secondary%20screening%20gives%20
very%20useful,small%20fermenters%20containing%20liquid%20media
.
• Secondary Screening - Creative Biolabs www.creative-
biolabs.com › therapeutics › secondary-s...
• Importance of secondary screening with clinical isolates for
...www.ncbi.nlm.nih.gov › pmc › articles › PMC6078976
• https://www.lawinsider.com/dictionary/secondary-screening