The importance of all the necessary nutrients for bacterial growth.

1. Effect of Different
Nutrients on Bacterial
Growth
Submitted By: Samrah Nadeem
MPhil Biochemistry

2. Nutrients for bacterial growth
⊹ Nutrients are necessary for microbial growth
and play a vital role in the proper cultivation of
microorganisms in the laboratory and in their
natural environments.
⊹ The nutrients used to propagate growth are
organism -specific, based on their cellular and
metabolic processes.
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3. Types of nutrients
⊹ Macronutrients are necessary in
large amounts.
× These are carbon, oxygen,
hydrogen, sulphur, calcium
and potassium.
⊹ Micronutrients are needed in
smaller amounts and are often
trace elements.
× These are manganese,
copper, molybdenum, zinc,
cobalt, and nickel.
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There are two main types of nutrients which are as follows:

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ELEMENT % OF DRY WEIGHT
Carbon 50%
Oxygen 20%
Nitrogen 14%
Hydrogen 8%
Phosphorus 3%
Sulfur 1%
Potassium 1%
Magnesium 0.5%
Calcium 0.5%
Iron 0.2%
Manganese Trace amount
Cobalt Trace amount
Zinc Trace amount
Copper Trace amount
Molybdenum Trace amount

5. Functions of Nutrients
⊹ Carbon
× Main constituent of cellular
material.
× Obtained by organic compounds
or CO2.
⊹ Oxygen
× Constituents of cell material and
cell water; O2 is a final electron
acceptor in aerobic respiration.
× Obtained by H2O, organic
compounds, CO2 and O2
⊹ Nitrogen
× Constituent of amino acids,
nucleic acids, nucleotides and co-
enzymes
× Obtained by NH3, NO3, organic
compounds, N2
× Nitrogen fixing bacteria for
converting N2 to ammonia.
⊹ Hydrogen
× Main constituent of organic
compounds
× H2O, organic compounds and H2
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⊹ Phosphorus
× Main constituent of nucleic
acids, nucleotides,
phospholipids, LPS and
techoic acids.
× Obtained by inorganic
phosphates (PO4).
⊹ Sulphur
× Constituents of cysteine,
methionine, glutathione and
coenzymes
× Obtained by SO4, H2S, organic
sulfur compounds.
⊹ Potassium
× Main cellular inorganic cation and
cofactor for few enzymes.
× Obtained by Potassium salts.
⊹ Magnesium
× Inorganic cellular cation, cofactor
for certain enzymes reactions.
× Obtained by Magnesium salts.
⊹ Calcium
× Inorganic cellular cation, cofactor
for certain enzymes and a
component of endospores.
× Obtained by calcium salts.

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⊹ Iron
× Component of cytochromes
and certain non-heme iron
proteins and a cofactor for
some enzymatic reactions.
× Obtained by iron salts.
⊹ Trace Elements
× Mostly involved as
cofactor for enzymes.
 Trace elements are metal ions required by certain cells in such small amounts that it is
difficult to detect 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 act as cofactors for essential enzymatic reactions in the cell. One
organism's trace element may be another's required element and vice-versa,
but the usual cations that qualify as trace elements in bacterial nutrition are Mn,
Co, Zn, Cu, and Mo.
For example, Zinc is present at the active site of several enzymes, Manganese involved in
catalysis of the transfer of phosphate group, Mo is essential for nitrogen fixation, etc.

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⊹ Growth factors
× Required in small amounts in
biosynthesis.
× The need for a growth factor results
from either a blocked or missing
metabolic pathway in the cells. .
I. Purines and pyrimidines: required for
synthesis of nucleic acids (DNA and
RNA)
II. Amino acids: required for the
synthesis of proteins
III. Vitamins: needed as coenzymes and
functional groups of certain enzymes.
Vitamin Function
p-Aminobenzoic acid (PABA) Precursor for the biosynthesis of folic acid
Folic acid
Transfer of one-carbon units and required for synthesis of thymine,
purine bases, serine, methionine and pantothenate
Biotin Biosynthetic reactions that require CO2 fixation
Lipoic acid Transfer of acyl groups in oxidation of keto acids
Nicotinic acid Electron carrier in dehydrogenation reactions
Pantothenic acid Oxidation of keto acids and acyl group carriers in metabolism
Riboflavin (B2) Oxidoreduction reactions
Thiamine (B1) Decarboxylation of keto acids and transaminase reactions
Vitamin B12 Transfer of methyl groups
Vitamin K Electron transport processes

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o Nutrients required for proper growth but the limiting factor or limiting nutrient affects and
controls growth.
o Proper availability dictates organismal growth
o Metabolic pathways are controlled properly for progress.
o During steady state: all requirements are present and microorganisms thrive.
o Growth gets affected in the absence of specific nutrients.
o Hence, it is critical to identify the required nutrients to ensure the production.
o The production of necessary components often controlled by the presence, and concentration
of a limiting nutrient.
Nutrients as Limiting Factors

10. Thank you!
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