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Growth Dynamics Of E. Coli In Varying Concentrations Of Nutrient Broths, PH, And
| Term Paper Title |
Growth Dynamics Of E. Coli In Varying Concentrations Of Nutrient Broths, PH, And |
| # of Words |
2591 |
| # of Pages (250 words per page double spaced) |
10.36 |
Growth Dynamics of E. coli in Varying Concentrations of Nutrient Broths, pH, and
in the Presence of an Antibiotic
Growth Dynamics of E. coli in Varying Concentrations of Nutrient Broths, pH, and
in the Presence of an Antibiotic
Dvora Szego,
Elysia Preston
Darcy Kmiotek,
Brian Libby
Department of Biology
Rensselaer Polytechnic Institute
Troy, NY 12180
Abstract
The purpose in this experiment of growth dynamics of E. coli in varying media
was to determine which media produces the maximum number of cells per unit time.
First a control was established for E. coli in a 1.0x nutrient broth. This was
used to compare the growth in the experimental media of 0.5x and 2.0x, nutrient
broths; nutrient broths with an additional 5.0mM of glucose and another with
5.0mM lactose; nutrient broths of varying pH levels: 6.0, 7.0, and 8.0; and
finally a nutrient broth in the presence of the drug/antibiotic chloramphenicol.
A variety of OD readings were taken and calculations made to determine the
number of cells present after a given time. Then two graphs were plotted, Number
of cells per unit volume versus Time in minutes and Log of the number of cells
per unit volume versus Time growth curve. The final cell concentration for the
control was 619,500 cells/mL. Four media, after calculations, produced fewer
cells than that of the control, these were: Chloramphenicol producing 89,3 01
cells/ml; glucose producing 411,951 cells/mL; lactose producing 477,441 cells/mL
and finally pH 6.0 producing 579,557cells/mL. The remaining four media, after
calculations, produced cell counts greater than the control: 2X with 1,087,009
cells/mL; 0.5X with 2,205,026 cells/mL; pH 8 with 3,583,750 cells/mL and finally
pH 7.0 with 8,090,325 cells/mL. From these results the conclusion can be made
that the environment is a controlling factor in the growth dynamics of E. coli.
This was found through the regulation of pH and nutrient concentrations. In the
presence of the drug/antibiotic, chloramphenicol, cell growth was minimal.
Introduction
E. coli grows and divides through asexual reproduction. Growth will continue
until all nutrients are depleted and the wastes rise to a toxic level. This is
demonstrated by the Log of the number of cells per unit volume versus Time
growth curve. This growth curve consists of four phases: Lag, Exponential,
Stationary, and finally Death. During the Lag phase there is little increase in
the number of cells. Rather, during this phase cells increase in
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