Escherichia Coli Growth Curve Essay Example

minutes, there is a more significant increase in microbial population. The next phase, log phase or exponential phase is a period characterized by “cell doubling” at constant rate. Generation time is the time interval required for the cells to double in number. The bacteria Escherichia coli have a generation time of about 20 minutes in nutrient agar.

This means that every 20 minutes, each cell present in the medium divides.If growth is not limited, doubling will continue. However, the exponential phase cannot proceed “indefinitely” because the medium will eventually be depleted of nutrients and filled with wastes. If we look in the graph, there is a steep part of the line from time 150 minutes onwards; this is the log phase or exponential phase. From an absorbance measurement of 0.

186 nm, the absorbance increased in a different manner as compared to the increase during the lag phase. For our result, we have only reached until this phase.Dilution of inoculum had to be done as well to be able to count microbial population in plates given that the manner in which the organism grows is exponential. In a normal microbial growth, the stationary phase follows the exponential phase. During this phase, the growth rate in the medium is equal to the death rate, resulting to a stationary growth.

This results from a growth-limiting factor since during the previous phase, there is cell doubling at constant rate and the medium has limited nutrients only. Lastly at death phase, bacteria run out of nutrients and die.