NUTRITION AND MEDIA OF MICRO-ORGANISMS

Microbial cells are structurally complex. Organisms need nutrients & a source of energy,

also known as ‘MICROBIAL NUTRITION’ to carry out numerous functions.

NUTRIENTS are substances used in biosynthesis of bacteria .

So that microbial nutrition is directly proportional to the microbial growth.

Therefore Growth is impossible without nutrition.

INTRODUCTION

MICRO-ORGANISMS ARE CLASSIFIED ON THE BASIS OF THEIR SYNTHESISIG CAPACITY AND THIER SOURCES:-

THESE NUTRIENTS ARE CATEGORISED AS:- 1. MACRO-NUTRIENTS OR MACRO-ELEMENTS2. OTHER MACRO-NUTRIENTS3. MICRO-NUTIENTS OR TRACE EEMENTS4. ORGANIC GROWTH FACTORS5. LIGHT6. WATER

1. THE MACRO-NUTRIENTS OR MACRO-ELEMENTS:-

o carbon, hydrogen, oxygen, nitrogen, phosphorus and sulphur.o They are essential elements because they required in large amounts.o They contain 95% of dry weight of the microbial cells.

NUTRITIONAL REQUIREMENTS OF BACTERIA:-

MACRO-NUTRIENTS

FUNCTIONS

CARBON Needed for the skeletons & backbones of all the organisms, molecules from which organisms are built.

OXYGEN & HYDROGEN

Available from water added to culture media for growth and found in organic molecules

NITROGEN Nature component of protein & nucleic acid . Sources are organic & inorganic nitrgeneous compound.

PHOSPHORUS

needed as a part of nucleic acid, co-enzyme NAD & FLAVIN & ATP.

SULPHUR It forms apart from the structure of several co-enzyme.

They all are components of carbohydrates, lipids, proteins, nucleic acids.

NUTRIENTS FUNCTIONS

POTASSIUM Helps in activity by a no. of enzymes that is including some involved in protein synthesis.

CALCIUM Contributes to the heat resistance of bacterial endo-spores.

MAGNESIUM Serves as a co-factor for many enzymes, complexes with ATP, & stablize ribo-somes & cell membrane.

IRON It is part of cyto-chromes & a co-factor for enzymes & electron carrying protein.

2. THE REMAINING FOUR MACRO-NUTRIENTS :- They exist in cell cations & a play variety of role.

Micro-nutrients are needed in small amounts.These nutrients are:- Magnese, zinc, cobalt, nickel &

copper.Cells require such small amounts that contaminates

from water, regular media components often are adequate for the growth.

They are normally a part of enzymes & co-factors. They aid in the catalysis of reactions &

maintainence of protein structure.

4. MICRO-NUTRIENTS OR TRACE ELEMENTS

Organic compounds that are essential cell compounds or precursors of such components are called ‘Growth factors’.

The major classes of growth factors are:- 1. AMINO ACIDS:- Needed for protein synthesis.2. PURINE & PYRIMIDINE:- Helps in nucleic acid

synthesis.

ORGANIC GROWTH FACTORS:-

VITAMINS:- They are small organic molecules that usually make up all or part of enzyme, co-factor & are needed in only very small amounts to sustain growth, also known as ‘bacterial vitamins’.

Some bacteria’s synthesis their own vitamins & while other need to take them from outside.

This varies from bacteria to bacteria.

Cotd.

Micro-organisms need light ( 250- 250 nm) for the photosynthesis of vitamins & minerals & for pigments.

6. WATERWater is important, because all nutrients should be in solution

form before they can enter in organisms.

ENVIRONMENT FACTORS:-There are some environment factors which also influenced to

microbial growth. These factors are like:-Air , Temperature, pH, Radiations, Osmotic pressure etc.

5. LIGHT

INTRODUCTION:- A Nutrient material prepared for the growth of micro-

organisms in a lab. Is called a ‘culture medium’.Some bacteria can grow well on just about any culture

medium.Others require special media & still others cannot grow

on any non-living medium yet developed.When microbes are introduces into a culture medium to

initiate growth, they are called an ‘inoculum’.The microbes that grow & multiply in or on a culture

medium , are referred to as ‘culture’.

CULTURE MEDIA

CULTURE MEDIA can be constructed completely from chemically defined components (defined media or synthetic media) or constituents like peptones & yeast extract(complex media).

Culture media can be solidifying by the addition of agar, a complex polysaccharide from red algae.

Culture media is needed to grow the organisms & the constituents are:-

1. Water:- i.e. source of hydrogen & oxygen.2. Electrolytes:- i.e. sodium chloride.3. Peptone:- it is a complex mixture of partially digest

protein.4. Meat extract5. Blood or serum 6. Agar:- which is used in 2-3% constituent. A small amount of protein & many

inorganic compounds.

CONSTITUENTS OF CULTURE MEDIA

S. NO

BASED ON PHYSICAL NATURE

BASED ON PRESENCE ON OXYGEN & NITROGEN

BASED ON CHEMICAL COMPOSITION

BASED ON FUNCTIONAL TYPE & SPECIAL MEDIA

1 LIQUID MEDIAe.g. nutrient broth

AEROBIC SIMPLE MEDIA:- W/c is routinely applied on the lab., To see motile bac. , E.g. soft agar

ENRICHED:- when basal medium add with other medium, like blood serum, agar. E.g. for growing streptococus

2 SEMI-SOLID MEDIA

e.g. soft agar

ANAEROBIC COMPLEX MEDIA :- contain some ingredients of unknown composition. Needed for growth of bacteria. E.g. nutrient broth etc.

ENRICHMENT:- it has stimulating effect of a bac. To grow or inhibit its compe-tatives.

TYPES OF MEDIA

3) SOLID MEDIA

e.g. nutrient

agar

SYNTHETIC MEDIA:- Prepared from pure chemicals, & used to study metabolic requirement.

SELECTIVE:- help in the isolation of a particular species e.g. DCA agar colony gives deoxycholate

4) DIFFRENTIAL:-it diffrentiate b/w 2 bac’s. e.g. Mackonkey’s agar diffrentiate b/w lactose & non-lactose fermenting.

5) INDICATORS:- It s colour change when a specific bac. Grows on it. E.g salmoneela .

6) TRANSPORT:- For delicate org. for transferring them.

7) SUGAR:- Helps in identification of bac..e.g. glucose et. Are needed in fermentation testhelps in identifying.

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