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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 extract
5. 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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