Arun- Microbial Growth & Factors Affecting Growth
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Microbial growth & Factors affecting growth
A . Arun Lecturer in Microbiology , Thiagarajar college , Madurai
Growth • In Physical term ØIncrease in size or number of Individual cell
• Many factors Ø Determine the cell to divide or grow
§ Physical factors – Environmental conditions, Temperature, O2, Pressure etc. § Chemical Factors pH, nutrient etc.
Growth in Prokaryotes • Various biochemical & physical events •
From
time it derived from parental cell
Until it divides in to two daughter cells
This period of time is called Bacterial cell cycle
Bacterial cell cycle • Characterized by Number of event q Growth – Coordinated synthesis of macromolecules as well as cellular components
q Septum formation q Division
Binary fission
Binary fission
Growth Phases Microbial populations
Batch culture
Continuous culture
Cells grown in batch nutrient
environment
Continuous nutrient environment
Growth curve
Cell have various Growth phases
Growth curve
Phases of growth
Phases of growth
Lag phase
Following Inoculation environment
Require some time to adjust to their new
Lag
Refers lag in cell division
During Lag
Increase
1. in size, Produce enzymes to metabolize the nutrients. 2. Synthesize RNA and Protein.
DNA remain constant
Lag Phase
Length of Lag phase
Is related to Physiological and genetic state of cell at the time of inoculation.
Cells Nutritionally starved If from nutritionally rich
long Lag phase short lag phase
Log phase (Exponential phase) • Phase at which cell division is maintained at a constant and maximum rate. e.g., In E.coli Nutrient rich Take 30 min to divide medium
e.g., In E.coli
Less nutrient rich medium
Take 60 min to divide
Log phase • Doubling time Remain constant in log phase Log Phase – said to be balanced growth In Log Phase – Cell population doubles .So also DNA , RNA & Protein In Batch Culture:
No nutrient enter No waste product removed
At one time: Reach a point – rate of growth slows down Due to the factors such as : Over crowding, Nutrietion depletion , pH etc End of the Log Phase : Trophophase – Primary metabolites produced
Stationary phase • Number of cells – Constant. Called as – Unbalanced growth
l components & macromolecules
Some cells
Synthesized at different rate
Divide and others die
Stationary phase
Cells which are alive
produce
2ndary metabolites and wastes
Idiophase
Death or Decline phase
Death of the cell increased
Continuous culture • In batch culture
it can not control the factors (Nutrient supply & waste removal)which decrease the growth rate.
To Overcome this problem – Continuous culture system can be used. q Primary purpose of continuous culture
To maintain cell population at constant rate
The devised used – Chemo stat & turbidostat
Factors affecting growth •
In addition to Chemical needs – also affected by physical nature of environment
• • Environmental factors – Temperature , pH, Osmotic pressure , radiation • • • Influence the growth of the particular organism
Temperature Growth Temperature
Influenced by Enzymatic reactions Plays Imp role Max Growth
Above (*)
Enzyme get denatured
Below (*)
Enzyme get inactivated
Temperature
Optimum growth temperature (*)
Based on Optimum growth temperature
Psychrophiles Mesophiles Thermopiles Hyper thermopiles
Psychrophiles • Grow • Found
Between 0°
to 20°c
Antarctic, cold soil, Stream, Ocean water, Rivers, Lake
mud.
• Role
Biodegradation in cold water lake, refrigerated foods.
Ribosome
Psychrophiles High Temperature
Unstable above 20°
protected from cold – unsaturated fatty acids Disrupt fatty acid Lysis
Cell content leak
Thermophiles • Grow
Between 40°C to 80°C. Some grow even in 90°C to 100°C.
Some G+ / G-Bacilli, Cyanobacteria, Photosynthetic bacteria
Thermophiles
- Present in hot springs - Have normal cell components as is mesophiles
With stand High temperature
Cell membrane components
Presence of polar amino acids in interior of cell
More branched, longer and saturated fatty acid
Mesophiles • Most Microbes Mesophiles • Temp Range - Between 25° to 40°c • Optimum Temp - 37°c
Osmotic pressure
Food with 12% salt No Microbes grow
Hydrostatic pressure
In every 10 meter
One atm. P increase
Hydrostatic pressure •
Barobiology – Study the effect of Pressure on Living things.
Barophiles/ Baro tolerant
Non Barophiles
Live in High pressure
Have gas vacuoles
Hydrogen ion concentration
Hydrogen ion concentration
Buffer system used
Hydrogen ion concentration Acidophiles
Types Basophiles
Neutrophiles
don’t have peptidoglycon layer Have Polyhexagonal array of protein for stability Fungi- Grow in pH 5 Bacteria - Grow in pH 7
Electromagnetic radiation
Microbes grow - Visible Range
Electromagnetic radiation
Phototrophs
Use light energy
A . Arun Lecturer in Microbiology , Thiagarajar college , Madurai
Growth • In Physical term ØIncrease in size or number of Individual cell
• Many factors Ø Determine the cell to divide or grow
§ Physical factors – Environmental conditions, Temperature, O2, Pressure etc. § Chemical Factors pH, nutrient etc.
Growth in Prokaryotes • Various biochemical & physical events •
From
time it derived from parental cell
Until it divides in to two daughter cells
This period of time is called Bacterial cell cycle
Bacterial cell cycle • Characterized by Number of event q Growth – Coordinated synthesis of macromolecules as well as cellular components
q Septum formation q Division
Binary fission
Binary fission
Growth Phases Microbial populations
Batch culture
Continuous culture
Cells grown in batch nutrient
environment
Continuous nutrient environment
Growth curve
Cell have various Growth phases
Growth curve
Phases of growth
Phases of growth
Lag phase
Following Inoculation environment
Require some time to adjust to their new
Lag
Refers lag in cell division
During Lag
Increase
1. in size, Produce enzymes to metabolize the nutrients. 2. Synthesize RNA and Protein.
DNA remain constant
Lag Phase
Length of Lag phase
Is related to Physiological and genetic state of cell at the time of inoculation.
Cells Nutritionally starved If from nutritionally rich
long Lag phase short lag phase
Log phase (Exponential phase) • Phase at which cell division is maintained at a constant and maximum rate. e.g., In E.coli Nutrient rich Take 30 min to divide medium
e.g., In E.coli
Less nutrient rich medium
Take 60 min to divide
Log phase • Doubling time Remain constant in log phase Log Phase – said to be balanced growth In Log Phase – Cell population doubles .So also DNA , RNA & Protein In Batch Culture:
No nutrient enter No waste product removed
At one time: Reach a point – rate of growth slows down Due to the factors such as : Over crowding, Nutrietion depletion , pH etc End of the Log Phase : Trophophase – Primary metabolites produced
Stationary phase • Number of cells – Constant. Called as – Unbalanced growth
l components & macromolecules
Some cells
Synthesized at different rate
Divide and others die
Stationary phase
Cells which are alive
produce
2ndary metabolites and wastes
Idiophase
Death or Decline phase
Death of the cell increased
Continuous culture • In batch culture
it can not control the factors (Nutrient supply & waste removal)which decrease the growth rate.
To Overcome this problem – Continuous culture system can be used. q Primary purpose of continuous culture
To maintain cell population at constant rate
The devised used – Chemo stat & turbidostat
Factors affecting growth •
In addition to Chemical needs – also affected by physical nature of environment
• • Environmental factors – Temperature , pH, Osmotic pressure , radiation • • • Influence the growth of the particular organism
Temperature Growth Temperature
Influenced by Enzymatic reactions Plays Imp role Max Growth
Above (*)
Enzyme get denatured
Below (*)
Enzyme get inactivated
Temperature
Optimum growth temperature (*)
Based on Optimum growth temperature
Psychrophiles Mesophiles Thermopiles Hyper thermopiles
Psychrophiles • Grow • Found
Between 0°
to 20°c
Antarctic, cold soil, Stream, Ocean water, Rivers, Lake
mud.
• Role
Biodegradation in cold water lake, refrigerated foods.
Ribosome
Psychrophiles High Temperature
Unstable above 20°
protected from cold – unsaturated fatty acids Disrupt fatty acid Lysis
Cell content leak
Thermophiles • Grow
Between 40°C to 80°C. Some grow even in 90°C to 100°C.
Some G+ / G-Bacilli, Cyanobacteria, Photosynthetic bacteria
Thermophiles
- Present in hot springs - Have normal cell components as is mesophiles
With stand High temperature
Cell membrane components
Presence of polar amino acids in interior of cell
More branched, longer and saturated fatty acid
Mesophiles • Most Microbes Mesophiles • Temp Range - Between 25° to 40°c • Optimum Temp - 37°c
Osmotic pressure
Food with 12% salt No Microbes grow
Hydrostatic pressure
In every 10 meter
One atm. P increase
Hydrostatic pressure •
Barobiology – Study the effect of Pressure on Living things.
Barophiles/ Baro tolerant
Non Barophiles
Live in High pressure
Have gas vacuoles
Hydrogen ion concentration
Hydrogen ion concentration
Buffer system used
Hydrogen ion concentration Acidophiles
Types Basophiles
Neutrophiles
don’t have peptidoglycon layer Have Polyhexagonal array of protein for stability Fungi- Grow in pH 5 Bacteria - Grow in pH 7
Electromagnetic radiation
Microbes grow - Visible Range
Electromagnetic radiation
Phototrophs
Use light energy
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