PHYSIOLOGY
OF BACTERIA
, Physiology of bacterial growth
Specific means by which bacteria acquire nutrients
to sustain its growth reflects its fundamental
physiological characteristics
In order to grow organism under laboratory
condition, it is essential to know the growth
requirements
For growth, bacteria must be provided with
•all of the substances essential for the
synthesis of protoplasm
•A source of energy, and
•Suitable environmental condition
, Physiology of bacterial growth
Following condition must be fulfilled in order
to grow bacteria in the laboratory
•Suitable nutrients must be supplied
•Optimum physical condition must be provided
However, bacteria are extremely versatile organism
They can utilize quite diverse food materials,
ranging from
•Completely inorganic substrates to
•Very complex organic compounds
,Growth requirements:
• Growth requirements are two types:
A. Nutritional requirements and
B. Environmental factors
A. Nutritional requirements are
1. Source of energy& Essential trace
elements
3. Growth factors
4
, Nutrient Requirements
1. Source of energy& Essential trace elements:
Essential elements for synthesis of bacterial structure
can be classified according to amounts required
•Macronutrients – required in large amounts.
Example – carbon, hydrogen, oxygen, nitrogen etc
•Micronutrients – required in small amounts and can
Example – copper, cobalt, manganese, molybdenum,
zinc etc.
, Carbon and energy source
Carbon source
⚫ Needed for synthesis of almost all parts of cell
⚫ Sources
⚫ amino acids
⚫ fatty acids
⚫ organic acids
⚫ sugars
⚫ and others – depends on microbe
, Carbon and energy source
Depending on carbon and energy sources,
microorganisms can be classified as
⚫ Heterotrophs
Dinoflagellates
⚫ utilize organic carbon as
energy sources
⚫ Autotroph
Myxobacteria
⚫ utilize inorganic carbon
(CO2) as source of energy
⚫ Phototrophs Purple Sulfur
Bacteria: a
⚫ harvest the energy of chemotroph
sunlight e.g., Cyanobacteria
, Carbon and energy source
⚫ Chemotroph
obtain energy by metabolizing inorganic
chemicals, e.g. Pseudomonas spp
⚫ Photoautotroph
utilize the energy of sunlight
Cyanobacteria
obtain carbon from CO2
primary producers of the microbial world
04k
6CO2 + 12H2O C6H12O6 + 6H2O + 6O2
⚫ photoheterotrophs
⚫ utilize the energy of sunlight Rhodobacter sphaeroides
⚫ obtain carbon from organic compounds
,Nitrogen
⚫ 12-15% dry weight of a cell
⚫ Needed for
⚫ amino acids-- -->proteins
⚫ nucleic acids----> DNA,
⚫ peptidoglycan
⚫ Sources
⚫ Organic
⚫ Amino acids
⚫ Nucleic acids
⚫ Inorganic
⚫ NO3-,(Nitrate) NH3, Nitrogen fixers can use
N2 (Nitrogen gas)
, Hydrogen and oxygen
⚫ Needed for much of cell
⚫ Constituents of organic matter and H2O
⚫ Oxygen: Also terminal electron acceptor in
process of aerobic respiration.
OF BACTERIA
, Physiology of bacterial growth
Specific means by which bacteria acquire nutrients
to sustain its growth reflects its fundamental
physiological characteristics
In order to grow organism under laboratory
condition, it is essential to know the growth
requirements
For growth, bacteria must be provided with
•all of the substances essential for the
synthesis of protoplasm
•A source of energy, and
•Suitable environmental condition
, Physiology of bacterial growth
Following condition must be fulfilled in order
to grow bacteria in the laboratory
•Suitable nutrients must be supplied
•Optimum physical condition must be provided
However, bacteria are extremely versatile organism
They can utilize quite diverse food materials,
ranging from
•Completely inorganic substrates to
•Very complex organic compounds
,Growth requirements:
• Growth requirements are two types:
A. Nutritional requirements and
B. Environmental factors
A. Nutritional requirements are
1. Source of energy& Essential trace
elements
3. Growth factors
4
, Nutrient Requirements
1. Source of energy& Essential trace elements:
Essential elements for synthesis of bacterial structure
can be classified according to amounts required
•Macronutrients – required in large amounts.
Example – carbon, hydrogen, oxygen, nitrogen etc
•Micronutrients – required in small amounts and can
Example – copper, cobalt, manganese, molybdenum,
zinc etc.
, Carbon and energy source
Carbon source
⚫ Needed for synthesis of almost all parts of cell
⚫ Sources
⚫ amino acids
⚫ fatty acids
⚫ organic acids
⚫ sugars
⚫ and others – depends on microbe
, Carbon and energy source
Depending on carbon and energy sources,
microorganisms can be classified as
⚫ Heterotrophs
Dinoflagellates
⚫ utilize organic carbon as
energy sources
⚫ Autotroph
Myxobacteria
⚫ utilize inorganic carbon
(CO2) as source of energy
⚫ Phototrophs Purple Sulfur
Bacteria: a
⚫ harvest the energy of chemotroph
sunlight e.g., Cyanobacteria
, Carbon and energy source
⚫ Chemotroph
obtain energy by metabolizing inorganic
chemicals, e.g. Pseudomonas spp
⚫ Photoautotroph
utilize the energy of sunlight
Cyanobacteria
obtain carbon from CO2
primary producers of the microbial world
04k
6CO2 + 12H2O C6H12O6 + 6H2O + 6O2
⚫ photoheterotrophs
⚫ utilize the energy of sunlight Rhodobacter sphaeroides
⚫ obtain carbon from organic compounds
,Nitrogen
⚫ 12-15% dry weight of a cell
⚫ Needed for
⚫ amino acids-- -->proteins
⚫ nucleic acids----> DNA,
⚫ peptidoglycan
⚫ Sources
⚫ Organic
⚫ Amino acids
⚫ Nucleic acids
⚫ Inorganic
⚫ NO3-,(Nitrate) NH3, Nitrogen fixers can use
N2 (Nitrogen gas)
, Hydrogen and oxygen
⚫ Needed for much of cell
⚫ Constituents of organic matter and H2O
⚫ Oxygen: Also terminal electron acceptor in
process of aerobic respiration.
