GROWTH OF BACTERIA
, Microbial Growth
All cells must accomplish certain physiologic
and metabolic activities to maintain growth
These activities include
•Uptake of nutrients
•Extraction of energy from the imported nutrients
•Synthesis of building blocks of proteins, polysaccharides and lip
•Polymerization of these building blocks into macromolecules
,
, Binary Fission
• asexual
• no genetic
recombination
• the DNA molecule
replicates itself
when bacterial
reproduction takes
place
E. coli undergoing cell division
, Bacterial Growth
• bacterial growth = bacterial cell reproduction
• the process of binary fission doubles the population e
time binary fission takes place
• this doubling time demonstrates exponential grow
• each generation results in a doubling of the populatio
• generation time is = to doubling time
• measure of microbial growth rate
, Rate of growth
⚫ Rate influences by
⚫ Genetic factors
⚫ Rate of enzymes activity
⚫ Speed of metabolism
⚫ Environmental factors
⚫ Availability of nutrient
⚫ Temperature
⚫ Oxygen concentration
⚫ E. coli under ideal conditions 20 minutes/cycle
⚫ Mycobacterium species 12-24 hours/cycle (~20 hours)
⚫ M. leprae - >20 days
, Rapidity of growth
It is important to realize the rapidity of growth
under favorable condition
E. coli double every 20 minutes
If this rate is maintained for 24 hours,
The mass would approximately 4000 tons
, Growth Curve
Batch Culture (Batch Growth Curve)
When a small number of organisms are inoculated in a medium,
number of cells may multiply a million fold
If the “number of cells present” at different times after inoculatio
is measured
And the number is “plotted in relation to the period of growth
The resultant plot is referred to as a “batch growth curve”
, Microbial Growth
All cells must accomplish certain physiologic
and metabolic activities to maintain growth
These activities include
•Uptake of nutrients
•Extraction of energy from the imported nutrients
•Synthesis of building blocks of proteins, polysaccharides and lip
•Polymerization of these building blocks into macromolecules
,
, Binary Fission
• asexual
• no genetic
recombination
• the DNA molecule
replicates itself
when bacterial
reproduction takes
place
E. coli undergoing cell division
, Bacterial Growth
• bacterial growth = bacterial cell reproduction
• the process of binary fission doubles the population e
time binary fission takes place
• this doubling time demonstrates exponential grow
• each generation results in a doubling of the populatio
• generation time is = to doubling time
• measure of microbial growth rate
, Rate of growth
⚫ Rate influences by
⚫ Genetic factors
⚫ Rate of enzymes activity
⚫ Speed of metabolism
⚫ Environmental factors
⚫ Availability of nutrient
⚫ Temperature
⚫ Oxygen concentration
⚫ E. coli under ideal conditions 20 minutes/cycle
⚫ Mycobacterium species 12-24 hours/cycle (~20 hours)
⚫ M. leprae - >20 days
, Rapidity of growth
It is important to realize the rapidity of growth
under favorable condition
E. coli double every 20 minutes
If this rate is maintained for 24 hours,
The mass would approximately 4000 tons
, Growth Curve
Batch Culture (Batch Growth Curve)
When a small number of organisms are inoculated in a medium,
number of cells may multiply a million fold
If the “number of cells present” at different times after inoculatio
is measured
And the number is “plotted in relation to the period of growth
The resultant plot is referred to as a “batch growth curve”
