Growth Dynamics Of E. Coli In Varying Concentrations Of Nutrient Broth :: essays research papers

Growth Dynamics of E. coli in Varying Concentrations of Nutrient Broths, pH, andin the Presence of an Antibiotic topThe purpose in this experiment of growth dynamics of E. coli in varying mediawas to rig which media produces the maximum turn of events of cubicles per unit time.First a control was accomplished for E. coli in a 1.0x nutrient broth. This wasused to comp atomic tot up 18 the growth in the experimental media of 0.5x and 2.0x, nutrientbroths nutrient broths with an additional 5.0mM of glucose and another with5.0mM lactose nutrient broths of varying pH levels 6.0, 7.0, and 8.0 and eventually a nutrient broth in the presence of the drug/antibiotic chloramphenicol.A variety of OD readings were taken and calculations made to determine thenumber of cells present after a given time. Then two graphs were plotted, Numberof cells per unit volume versus Time in minutes and Log of the number of cellsper unit volume versus Time growth curve. The final cell concentration for thec ontrol was 619,500 cells/mL. Four media, after calculations, produced fewercells than that of the control, these were Chloramphenicol producing 89,3 01cells/ml glucose producing 411,951 cells/mL lactose producing 477,441 cells/mLand finally pH 6.0 producing 579,557cells/mL. The remaining quaternity media, aftercalculations, produced cell counts greater than the control 2X with 1,087,009cells/mL 0.5X with 2,205,026 cells/mL pH 8 with 3,583,750 cells/mL and finallypH 7.0 with 8,090,325 cells/mL. From these results the conclusion can be madethat the environment is a controlling factor in the growth dynamics of E. coli.This was found through the rule of pH and nutrient concentrations. In thepresence of the drug/antibiotic, chloramphenicol, cell growth was minimal.IntroductionE. coli grows and divides through asexual reproduction. Growth will continueuntil all nutrients are depleted and the wastes rise to a toxic level. This isdemonstrated by the Log of the number of cells per unit vol ume versus Timegrowth curve. This growth curve consists of four phases Lag, Exponential,Stationary, and finally Death. During the Lag phase there is little increase inthe number of cells. Rather, during this phase cells increase in size bytransporting nutrients inside the cell from the medium preparing forreproduction and synthesizing DNA and various enzymes needed for cell division.In the Exponential phase, also called the log growth phase, bacterial celldivision begins. The number of cells increases as an exponential function oftime. The third phase, Stationary, is where the culture has reached a phaseduring which there is no net increase in the number of cells. During the