The document discusses the nutritional requirements and culture media for bacterial growth. It outlines the major elements, trace elements, and growth factors that bacteria need to grow, such as carbon, nitrogen, vitamins, and minerals. It also categorizes bacteria based on their nutritional types as either autotrophic or heterotrophic. Autotrophs can synthesize their own food while heterotrophs rely on external organic sources. The document also defines culture as microorganisms cultivated in the lab and medium as the combination of ingredients that support microbial growth by providing essential nutrients. Common growth media include nutrient broths and agar plates.
2. GROWTH REQUIREMENT & NUTRITIONAL REQUIREMENTS
Growth is an orderly increase in the quantity of cellular constituents. For
most bacteria, growth involves increase in cell mass and duplication of
the bacterial DNA ,synthesis of new cell wall and cellular membrane and
finally cell division. Every organism must find its environment to find the
substances required for energy generation and cellular biosynthesis.
The chemical and elements of this environment that are utilized for
bacterial growth are referred to as nutrients and nutritional requirement .
Many bacteria can be grown in the laboratory in culture media which are
designed to provide all the essential nutrients for bacterial growth.
3. GROWTH REQUIREMENT
The Various requirement for bacterial growth are:
Major Elements: These include C, H, O, N, S, P ,K, Mg Fe, Ca. These elements are found in the
form of water, inorganic ions, small molecules, and macromolecules which serve either a structural
or functional role in the cells.
4. GROWTH REQUIREMENT
The Various requirement for bacterial growth are:
Trace elements: These are metal ions required by certain cells in small amounts that it is difficult to
detect (measure) them, and it is not necessary to add them to culture media as nutrients. Trace
elements are required in such small amounts that they are present as “contaminants” of the water or
other media components. As metal ions, the trace elements usually act as co factors for essential
enzymatic reactions in the cell. Some of the trace elements in bacterial nutrition are Mn, Co, Zn, Cu,
and Mo.
5. Growth Factors: An organism, whether it is an autotroph or a heterotroph, may require small
amounts of certain organic compounds for growth; such compounds are called growth factors.
Growth Factors are required in small amounts by cells because they fulfill specific roles in
biosynthesis. Growth factors are organized into three categories:
1. Purines and pyrimidines: required for synthesis of nucleic acids (DNA and RNA)
2. Amino acids: required for the synthesis of proteins.
3. Vitamins: Vitamins (p-Aminobenzoic acid, folic acid, biotin, lipoic acid, pantothenic acid,
nicotinic acid, Vit. B,B2,B6,B12and Vit K) are needed as coenzymes and functional groups of
certain enzymes.
6. NUTRITIONAL TYPES OF BACTERIA
On the basis of carbon and energy sources for growth, bacteria are broadly divided into two groups:
1. Autotrophic Bacteria:
The Bacteria which are able to synthesize their own organic food from inorganic substances
supplied from environment are called autotrophic bacteria and thus mode of nutrition as autotrophy or
autotrophic nutrition. Theses bacteria can be distinguished further into two types as follows:
a) Photoautotrophic Bacteria: Theses Bacteria utilize solar energy to synthesize their organic
metabolites as they possess photosynthetic pigments in membrane bound lamellae
7. NUTRITIONAL TYPES OF BACTERIA
b) Chemoautotrophs or Chemosynthetic Bacteria: These are non-photosynthetic bacteria which
manufacture organic compounds from inorganic raw materials and utilize energy liberated from
the oxidation of these inorganic substances.
8. 2. Heterotrophic Bacteria:
The bacteria which are unable to manufacture their own organic food and hence are dependent
on external source are called heterotrophs and the mode of nutrition as heterotrophy or
heterotrophic nutrition. These bacteria can be further distinguished into two groups:
a) Photoheterotrophs : They are considered to be intermediate between photoautotroph’s and
chemoheterotrophs because they posses unique feature of utilizing light energy (like
photoautotrophs) in synthesizing their food from organic raw materials absorbed from
environment. They therefore, do not use inorganic raw materials to synthesize their food.
9. b) Chemoheterotrophs : Majority of heterotrophic microorganisms belong to this category. Since
they cannot synthesize their own food (organic substances) they obtain it directly from external
environment using organic compounds.
16. CULTURE AND THE
MEDIUM
CULTURE
Is the term given to microorganisms that are cultivated in the lab for the
purpose of identifying and studying them.
MEDIUM
Is the term given to the combination of ingredients that will support the
growth and cultivation of microorganisms by providing all the essential
nutrients required for the growth (i.e. multiplication) in order to cultivate these
microorganisms in large number to study them.
17. Microbiological culture: which are used for growing microorganisms, such as
bacteria or yeast
The most common growth media for microorganisms are nutrient broths and agar
plates
Specialized media are sometimes required for microorganism and cell culture
growth
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27. D) Depending upon functional type
Enriched media
Enrichment media
Selective media
Indicator media
Differential media
Sugar media
Transport media
