PRESENTED BY

L.SUKANYAGANDHI

II-MSC FOOD SCIENCE AND NUTRITION

INTRODUCTION

The microorganisms posses tremendous

capacity to produce a wide range of products that

have commercial value.

The primary and secondary metabolisms and

bioconversions of microorganisms with special

reference of their importance for the formation of

biotechnologically important products.

PRIMARY METABOLITES:

Primary metabolites also referred to as

trophophase is characterized by balanced growth of

microorganisms. It occurs when all the nutrients

needed by the organisms are provided in the

medium.

In the trophophase, the cells posses optimal

concentrations of almost the macromolecules

(protein DNA, RNA etc.)

It is during the period of trophophase, an

exponential of microorganisms occurs.

several metabolites, products are produced in

trophophase(I,e during the period of growth).

The primary metabolites are divided into two groups.

primary essential metabolites

primary metabolic end products

1.PRIMARY ESSENCIAL METAMALITES:

These are the compounds produced in adequate quantities to sustain cell growth e.g. vitamins, amino acids, nucleosides.

2.PRIMARY METAMOLIC END PRODUCTS:

These are the normal and traditional end product offermentation process of primary metabolism.

The end products may or may not have any significantfunction to perform in the microorganisms, although theyhave many other industrial application.

E.g ethanol, acetone, lactic acid.

As the exponential growth of the microorganisms

ceases (i.e. as the trophophases ends) they

enter idiophase.

Idiophase is characterized by secondary

metabolism where in the formation of certain

metabolites, referred to as secondary

metabolites (idiolites) occurs.

CHARACTERISTICS OF SECONDARY METABOLITES:

Secondary metabolites are specifically produced by

selected few microorganisms.

They are not essential for the growth and reproduction

metabolites.

The biosynthetic pathways for most secondary metabolites

are not clearly established.

The regulation of the formation of secondary metabolites

is more complex and differs from that of primary

metabolites.

FUNCTIONS:

As already stated secondary metabolites are not

essential for growth and multiplication of cells.

The secondary metabolites may perform certain

(unknown) functions that are beneficial for the cells to

survive.

The secondary metabolites have absolutely no function.

Their production alone is important for the cell, whatever

may be the product. (which is considered to be useless).

There are over a million species of microorganisms

widely distributed in nature.

Less than 1% of the world’s microorganisms have

been studied.

In fact only a few hundred species are important for

industrial use.

MICROORGANISMS PRODUCTS

ALGAE:

Chlorella sorokiniana

Spirulina maxima

Single-cell protein

Single-cell protein

BACTERIA:

Acetobacter acetic

Bacillus subtitis

Acetic acid.

Bacitracin.

ACTINOMYCETES:

Streplomyces aureoraciens

Micromonospera purpurea

Tetracycline

Gentamycine.

FUNGAI:

Aspergillums' Niger

Candida lipolytica

Citric acid

lipase

The good sources for the isolation of microorganisms are soils,

lakes and river mud's.

It is estimated that a gram of soil contains 10-10 bacteria, 10-10

acitomycete spores and 10-10fungal spore.

The common techniques employed the isolation or microorganisms are given below.

1. Direct sponge of the soil.

2. Soil dilution.

3. Gradient plate method

4. Aerosol Dilution

5. Flotation

6. centrifugation.

The general scheme adopted for isolating microorganism from

soil or water source is given below.

The sample is diluted with sterile water to which on emulsifying

agent is added.

Sample is thoroughly mixed and allowed to stand at room

temperature.

Supernatant is diluted 10-1 to 10-1

Various culture media are inoculated with diluted samples and

incubated.

Colonies from the plates are isolated & identified.

The required pure stains are maintained and preserved.

Screening is the next important step in bio processing, where the

isolates are investigated for producing the desired product .

Screening BASICALLY OF TWO TYPES:

Primary screening

Secondary screening

Primary screening is checking the quality of microbes. most cases

of primary screening are done on agar plates.

Secondary screening is checking of isolates for their quantitative

production in liquid media.

PRIMARY SCREENING:

Primary screening for enzyme is done by culturing the isolates in

agar plates incorporated with specific substrate.

The production of a specific enzyme can be detected in two

ways: by observing the substrate utilization zone around the

colonies of isolates or by adding reagents to the end product of

the reaction, which shows the utilization zone.

Secondary screening deals with production in liquid and

quantification of products.

The product can be evaluated with agar plates and other

appropriate methods.

Secondary screening of enzymes is done through well-

method in agar plates.

The agar plates are incorporated with specific

substrates and wells are made in therm.

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