Control Of Microbial Growth ( Part 1

The purpose of this experiment is to investigate the effects of various household products may have on bacterial growth. The bacteria that was chosen as a test subject is Micrococcus luteus, which is generally considered a harmless bacterium unless the host has a weakened immune system. Among the household products that a set of groups will test are common cleaning and disinfecting products such as rubbing alcohol, Betadine, Germ-X, Neosporin, liquid hand soap, and Lysol cleaner. In the experiment, the bacterium, Micrococcus luteus, is to be swabbed and grown in a Petri dish divided into four sections with agar in each. After that, a small circle of thin paper is soaked in the four household items. Then, a piece of parafilm

The water activity also plays a big role in the microbes ability to survive as most cannot grow in a water activity level less than 0.91. Based on observations and construction of a data table, it was shown that the 1% NaCl solution had a water activity level of 0.99, the 7% NaCl solution 0.96 and the 15% NaCl solution 0.91. Based on the table it was expected that there would be no growth in the 15% NaCl solution as most microbes cannot survive at a water activity level of 0.91.

In the beginning of lab, we were advised to obtain a nutrient agar petri plate, which is used for the cultivation of microbes supporting growth of non-fastidious organisms. Since it contains many nutrients, a wide variety of bacteria and fungi can grow. Taking the plate,

For many years the identification of microorganisms has been important in the world of medicine. It is essential or correct disease diagnosis in patients and for proper treatment. Knowing the correct identity and characteristics of microorganism is crucial when disease outbreaks occur in populations, also knowing how humans can benefit from microorganisms is important; many can be used in making certain foods or antibiotics.

A) Heat is an effective means of sterilization because it destroys the proteins of microbial

The purpose of this report is to analyse the growth of the bacteria known as Citrobacter Freundii as well as distinguishing what antibiotics effect its growth. This will be done so by answering the following question after completing its associated experiments. This question includes: what antibiotics are most effective in denaturing the bacteria? It has been predicted that chloramphenicol will be the most effective due to the fact that its medical uses are treating meningitis which is an infection caused by Citrobacter freundii. After conducting the experiments it was found that the chloramphenicol antibiotic was the most effective in denaturing the bacteria, although streptomycin was also affective. However, none of the other antibiotics were able to halt the growth of the bacteria.

You can grow microorganisms in liquid media or on solid media. Most bacteria can be grown in labs as long as the media contain a source of the major nutrients; carbon, nitrogen, sulphur, and phosphorous. They may also need to have other nutrients. These nutrients are made into a broth and the pH and salinity can be adjusted. The nutrient broth is placed in test tubes, which are plugged with cotton wool, capped with foil and then sterilised in an autoclave, at 121c for 20minutes. These tubes are then cooled before they are inoculated. To prepare the streak plates we dipped an inoculating loop into ethanol then placed it in the flame until the loop glowed red. Still holding the inoculating loop by its handle we removed the lid from

Controlling the growth of microorganisms is not always necessary, but when they become a danger to society there is a need. There are several effective ways that are used to either control or destroy the microorganism. Bactericidal refers to the killing of microorganisms and bacteriostatic refers to inhibiting the growth. Heat is most often used for killing microorganisms. Some examples of heat would be incineration which is used for needles, inoculating wires and glassware. Boiling is used for to kill endospores and sterilize a solution. Autoclaves use pressurized steam which can denature or destroy heat labile substances, but is good for sterilizing almost everything. A hot air oven ( dry heat) is used for glassware, metal and objects that do not melt. Hospitals use autoclaves to clean surgical instruments and anything that would be used for multiple patients. Some items are made for one time uses, such as for a patient that is isolation for an infectious microorganisms that

These organisms need energy from nutrients to do their job (Advanced Biotech, 1995-2015). There are two types of this, bio stimulation and bio augmentation (Advanced Biotech, 1995-2015). In stimulation, nutrients are added to the water, therefore depending on the microbes being in the water (Advanced Biotech, 1995-2015). Not all forms of microbes can break down every type of bacteria. In the process of augmentation, scientifically chosen micro-organisms are added to the water and monitored, therefore being more effective than stimulation because it is positive that the organism(s) being added are the right type and will do the job (Advanced Biotech, 1995-2015). Some benefits to this process are that it is very effective in killing the bacteria and it will work quickly once it is effective. Once the bacteria and micro-organism types are identified, this method is sure to work. Once the organisms are added, it won’t be long before they are done breaking down the bacteria. However, there are some downsides. This method could take lots of time to find the right organisms to kill off the bacteria. Not only will it take long, but it could be costly to purchase the right type of micro-organism to kill of that specific type of

This experiment is about bacterial growth. We will demonstrate a bacterial growth curve using a closed system. Bacterial growth usually takes up to 12-24 hours to get an accurate result so we will be monitoring this growth between two classes. We also used different methods to determine bacterial growth as well as a few different calculations. One way of receiving data is by using a spectrophotometer where we will record the absorption at a given time to create the bacterial growth curve. We also used the plate count method after performing a serial dilution to calculate the actual cell density at different times given. By using this method we can count the population number of the same given and see the maximum cell density

There was no difference between the control plates which proves that the lid on the plate serves as significant protection, potentially shielding the bacteria to the mutagenic effects the UV light. All three plates were incubated at 25 degree Celsius. The first Control plate showed lots of red and furry growth and the original pattern of swiping was observed in all the quadrants. The second control plate was also observed to have furry and pigmented red growth in all the quadrants, despite being exposed to UV light due to the plate lid during exposure. The experiment plate showed the most interesting results, in the 10 second UV exposure quadrant the bacteria had red pigmented growth but it is speckled, pinpointed and the original swipes were not observed. Moreover the growth seemed not as furry and robust as the control plates. The quadrant exposed to 20 sec of UV light showed significantly less growth than the 10 sec quadrant and the colonies are pinpointed with several beige colonies in between the red speckles. Original swipe pattern of the bacteria was not observed in this colony. In the quadrant exposed to 30 seconds of UV light, the differences are even more significant as the colonies are few and far in between and only several pinpoint red colonies found with a few beige colonies and some colonies with red centers surrounded by beige. The effects of UV light are very drastic in the 40 second quadrant as the growth is severely diminished with only a

Being able to control bacterial growth is something that is important in our everyday lives. As shown in the previous labs, bacteria can grow and create colonies extremely quickly especially in the right environments. By acknowledging this, it is then important to get an understanding of how bacterial growth can be controlled by humans. To control microorganisms it means to inhibit their growth (static) and or kill them (cidal) (Kenneth Todar, 2015); therefore since focusing on bacteria the terms bactericidal and bacteriostatic are both extremely important for this lab. One broad method we will use to control bacterial growth is heat. The amount of heat needed to control bacterial growth is different for different species of bacteria (Kenneth Todar, 2015). Bacteria can also respond differently depending if moist heating method such as an autoclave with steam is used, or a dry heating method such as inoculating a loop over a fire is used (Kenneth Todar, 2015). UV works by damaging the cells DNA, without proper DNA, the cells will die and the object

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.

Microbial growth can be affected by different environmental factors such as temperature, osmotic pressure, oxygen concentration and pH. Six experiments were carried out in this report testing for microbial growth against different environmental factors. Good aseptic techniques were used to prevent contamination, resulting in a uniform set of results that are in line with the literature.