Lab Report On Bacterial Growth

The conditions needed for the growth of micro-organisms are: Micro - organisms need food to survive. They like high protein food to survive, eg. Poultry & fish. Most micro - organisms need warmth & grow best at 20-40c. They need moisture to multiply. They need air to multiply, though some can without. A single Micro-organism becomes two every twenty minutes.

Citrobacter Freundii is a species of bacteria that can be potentially harmful to humans. It is known to cause meningitis by protruding into the brain and replicating itself (1). The Citrobacter species has also been found as a cause of some urinary tract infections, diarrhea, and even gastrointestinal diseases and symptoms (3). C. Freundii can be located in a wide variety of soils and water (3). Lastly, it is also the cause of many nosocomial infections due to its presence in water (1).

Background information: In this lab you will be looking at the growth of bacteria under different conditions to see the how populations of bacteria grow. Read about cells in the text or e-text. For everyone, in your e-text read chapter 13, sections 13.3 and 13.4 to learn more about bacteria. Then answer the questions below.

As shown in the figure above, it is evident that V.natriegens grew faster when the Brain Heart Infusion (BHI) broth contained 250mM NaCl. The # of bacterial cells at each time point was measured following the equation given in the “How to generate a bacterial growth curve” supplemental material posted on D2L. (2) The data was then recorded in the table listed above. A growth curve graph was constructed using the data above which illustrated the differences between each of the different BHI mixtures. The graph was then used to determine the generation time of V.natriegens for each different environmental condition. In order to calculate the generation time (g) the mean growth rate (k) must be calculated. The formula to do this is posted in the supplemental material “How to generate a bacterial growth curve” on D2L. The k value calculated for each condition goes as follows:

Microbe growth can be influenced in a number of ways. One influence is pH. Most bacteria thrive around pH values that are neutral, although some can grow in extremely acidic environments (Blamire, 2000). Nutrient availability can also have an impact on microbial growth. Nutrients can

Bacteria grows exponentially in the first phase of fermentation (acidogenesis phase) along the formation of acids (mostly acetate and

Introduction Microbiology is the study of microorganisms that live unseen by the naked eye. This field delves into the morphology, physiology, and biochemical aspects of bacteria, viruses, yeast, protozoa and archaea. Microorganisms play a vital role in every form of life from plants to animals. There are many branches within the field of microbiology that are broken down into two groups; pure and applied. The study of pure microbiology includes six main branches; bacteriology, mycology, phycology, protozoology, virology, and parasitology (Maruthi, n.d.).

Before starting the experiment we believed that the high light and high nutrient treatment would cause bacteria to grow more quickly because it had all resources available for the bacteria to be successful in having a high growth rate and doubling time. This sample would experience the least amount of limitations. With that being said, the expected treatment with the lowest growth and doubling rate would have to be the low light and low nutrient treatment.

showed that the rate of the growth of bacteria increased with the increase in the incubation period, the

In this lab experiment, students had to create a growth curve for E. coli. The E. coli growth curve would illustrate the progression of the population of E. coli a set time period. In this case, the growth curve depicted the population of E. coli over a 12-hour period. The growth curve for E. coli was created from the absorbance levels, the optical density(OD), recorded from the spectrophotometer.

Bacteria grown in a closed system show a specific growth pattern called the growth curve which consists of four phases. The lag phase, which is a period of slow growth; exponential phase, period of maximum growth; stationary phase, where nutrients become the limiting factor making the growth rate equal to the death rate and the death phase where organisms die faster than they are replaced. It is important to know how fast a microbe grows in order to know bactericidal or antibiotic concentrations, temperature and ph at which they stop growing. Evaluating a growth curve gives you a perspective of the generation time and the mean growth

The purpose of the two experiments was to determine the fundamental effects that temperature has on the growth and survival of bacteria. During the first experiment five different bacterial broth cultures of Escherichia coli, Pseudomonas fluorescens, Enterococcus faecalis, Bacillus subtilis and Bacillus stearothermophilus were individually incubated at temperatures of 5, 25, 37, 45 and 55°C for one week in an aim to distinguish the effect temperature has on growth and survival of the five different species. After one week they were observed for distinguishable changes by the turbidity showing an indication of bacterial growth, or the clarity an indication of no survival.

This experiment was performed to test the hypothesis if LB nutrient broth, +pGLO and -pGLO Ampicillin, and Arabinose was placed in the E. coli plates, then there will be a significant growth in the newly transformed bacteria and it will possess the ability to glow under UV light. The measurements were recorded from the bent glass tube in each glass test tube. The transformation protocol tested for the newly possessed traits in E.coli bacteria. Throughout the experiment there were many probable reasons for failure. If the pipettes and sterile loop were not thrown out in between each use, a cross contamination could cause a miscalculation in the experiment causing the data results to fail. The hypothesis that was tested was validated due to the positive results with each experiment stating that newly transformed organisms due in fact pass on traits.

The bacterial growth can be characterized into four distinct stages namely, lag phase, exponential phase or log phase, stationary phase, decline or death phase. In the lag phase, contextual organism acclimatized with the surroundings (Mohandas et al. 2017). In this phase, the cell grows but do not replicate. Thus, no growth in cell mass is observed here. However, in the exponential phase, the organism grows fast and divide rapidly. The observation denotes that with the increase in the salinity or the concentration of the NaCl in

The cells divide at a constant rate depending upon the composition of the growth medium and the conditions of incubation. The rate of exponential growth of a bacterial culture is expressed as generation time, also the doubling time of the bacterial population ( the doubling time in fast growing cells is less as compared to the slow growth). The microorganisms are rapidly growing and heir