lls are preparing for division. They are making sure to manufacture fats and proteins for the reproduction ahead. The second phase is the log (logarithmic or exponential) phase. The bacteria is now replicating rapidly and becoming so large in numbers that space is growing smaller, as is non-hazardous room and nutrient. Due to this rapid growth, the next step is the stationary phase. In this phase, about fifty percent of the new bacteria population will become inactive, and the other fifty percent will remain and continue replication (binary fission). The last stage of bacteria generational grow is the death stage. In the death stage, there is not enough nutrients for the entire population. This causes the death rate of E. coli to increase, and the division will slow as well. At some point, the birth rate will be lower than the death rate, and this is displayed in the graph at the leveling off, or downward slope. From this growth curve that bacteria produces, the mean generation time (MGT) can be calculated. This will be shown later in the results section of this report. Various types of abiotic, "non-living chemical and physical factors (Biology, 1027)", factors try to decide which will act as catalysts and which will limit the growth of the E. coli. There are many factors that could have an effect on the growth rate of bacteria, but we are only concerned withthree; aeration, temperature, and nutrients. "The conditions for optimal growth-temperature, pH, salt concentrations, nutrient sources and so on- vary according to species. Refrigeration retards food spoilage because most microorganisms grow only very slowly at such low temperatures (Campbell, 507). Temperature acts as a catalyst for many things, and it helps speed up many chemical processes. It is stated in the lab manual ( 35) that 37 degrees Celsius is the optimal condition for E. coli and that E. coli has a doubling time of about 20 minutes at this temperatur...
