Please enable JavaScript.
Coggle requires JavaScript to display documents.
Microbial Growth & Growth Control - (ii Population Growth),…
Microbial Growth & Growth Control - (ii Population Growth)
Quantitative aspects of microbial growth
Most bacteria have shorter generation time than eukaryotic microbe
Generation Time is dependent on medium and incubation condition
Exponential growth- Growth of microbial population in which cell numbers double within specific time interval
During exponential growth,the increase in cell number is initially slow but increases at a faster rate
N(final cell number) =No2n
g(generation time) =t/n
spec. growth rate (K) =0.301/g
division rate (v) =1/g
Continuous Culture
Chemostat (most common type of continuous culture device)
Both growth rate and population density of culture can be controlled independently and simultaneously
Dilution rate- rate at which fresh medium is pumped in and spent medium is pumped out
1) In a chemostat, growth rate is controlled by dilution rate
2) The growth yield (cell number/ml) is controlled by concentration of the limiting nutrient
chemostat culture are sensitive to dilution rate and limiting nutrient concentration
at high dilution rate, the organism is wshed out
at low dilution rate, the cell may die from starvation
Increasing in concentration of limiting nutrient result in greater biomass but same growth rate
Continuous culture- an open-system microbial culture of fixed volume
Growth Cycle
Typical growth curve for population of cell in a closed system is characterized by 4 phases
Exponential phase- cell in this phase are typically in the healthiest state
Stationary phase- growth rate of population is zero, - either essential nutrient is used up or waste product of the organism accumulate in the medium
Lag phase- interval between inoculation of a culture and beginning of growth
Death phase- the cell eventually die
Batch culture- a closed-system microbial culture of fixed volume
In batch culture, the growth condition is constantly changing; it is impossible independently to controlled both parameters