Using Selective Media to Monitor the fermentation process of Cabbage and Cucumber, for Fourteen Days Abstract: Introduction: The goal of the ecological succession lab is to demonstrate succession with the fermentation of cabbage and cucumbers. The cabbage will ferment into sauerkraut and the cucumber will ferment to pickles during fermentation process that will changes the species structure and the community of time. During the fermentation process we watched the pH become more acidic, since the desired bacteria would produce lactic acid.
The lactic acid would control by inhibiting the spoilage of the cabbage or the cucumber. This was seen by the increase of the acidity in both of the environment, which was seen as the pH went from a neutral 7. 0 to a relatively acidic 4. 0. The drop in the pH from the acid production from lactic fermentation, and are know as lactic acid bacteria. (Foster, 2009) Typically, these bacteria are Lactobacillus spp. , Streptococcus spp. and Pediococcus spp. seen to have the highest bacterial counts of 4. 5 *10 6 to 4. 3 *107 CFU/mL on the WN5 (microaerophilic) and the LSD plates for the cabbage in our experiment (Foster, 2009).
The bacterial counts were the highest for the lactic acid producing bacteria. The initial salt saturation of 5% with the tap water. The lactic acid bacteria can tolerate the salt and it help deter the unwanted bacteria and aid in the production of acid. The following predictions for the five plates are as follows, the TSA plate will gradually increase and then plateau. Also, the WN5 plate would increase over time and plateau; that was the same case for the LSA plate. The PS and the EC plates would both spike initially in growth and then drop off to less than 1. *101 CFU/mL Material and Methods: The materials for the fermentation experiment were, fermentation jars, first was gas pack jar (anaerobe) and second was a candle jar (microaerophilic).
Abstract. One of the most fundamental differential staining techniques used in the study of bacteriology is gram staining. There are two main types of bacteria, gram negative and gram-positive. The purpose of this experiment was to perform a variety of tests to identify the bacteria contained in the unknown sample labeled number 15. The following are the tests that were used to identify the two ...
Then at the start of the experiment was eight selective media agar dishes: 3-TSA (control), 2-WN5, a PS, a EC and 1-LSA. After day 7 we were able to combine the aerobic TSA dishes. Additional materials were, pH strips, test tubes, P-200 micropipette, 3-mL syringe and fermentation jar. The pH was measured with the aid of pH indicator strips, to determine if the pH was dropping or rising.
The dilutions were performed with the P-200 micropippetor, the dilution factors changes through the experiment, in relation to the bacterial growth and ranged from 10-1 to 10-5. The fermentation jar was packed with ? of a head of lettuce and 5% salt-water solution from the sink. The 5% solution was achieved by using 25g of salt in 500mL of H2O. The TSA agar plates were the control environments, one aerobic and the other anaerobic. The WN5 was for the anaerobic and microaerophilic conditions and had cyclohexane and 5% salt that selects for bacteria. The PS agar dish had CFC supplement (cetrimide, fucidin and cephalonidine) and Irgasam.
The EC dish had bile salt that selected for Gram-negative bacteria. The LSA plate allowed for the differentiation of lactobacilli and streptococci. All of the above plates were incubated at room temperature of 25°C. The plates were counted for formed colonies on the following days: 0,2,7,9 and 14; also the pH was taken. The pH was taken by removing some of the fermentation liquid and placed on the indicator strip. Results: The cabbage pH went from a neutral 7. 0 to 4. 0, which was relatively acidic. Refer to figure 1 and 2 to see how the population of each bacterium changed from day 0 to 14.
Comparison chart Embed this chart Aerobic Respiration Anaerobic Respiration DefinitionAerobic respiration uses oxygen. Anaerobic respiration is respiration without oxygen; the process uses a respiratory electron transport chain but does not use oxygen as the electron acceptors. Cells that use itAerobic respiration occurs in most cells. Anaerobic respiration occurs in bacteria, yeasts, some ...
The cabbage’s number of colonies that were counted on each plate and the total dilution for each plate would be found in figure 1(table 1).
In addition, figure 2, had the bacterial colonies for cabbage in CFU/ml; that grew on the respective plates during the fermentation process and was similar to figure 1. The figure 3 the graph for the fermentation for 14 days of cabbage and the respective bacterial counts in CFU/ml (log 10).
The graph showed an increase for the LSD [aerobic] and the WN5 [microaerophilic]. In addition, the WN5 [anaerobic], TSA [anaerobic & aerobic], all basically had a little rise and then plateaued from day 2 to 14.
Also, the PS and EC [aerobic], both rose a little and declined to 1. 0 *101 from day 2 to 14. The cucumber pH most likely followed the same trend of neutral 7. 0 to 4. 0, which was relatively acidic. Refer to figure 4 and 5 to see the population changed from day 0 to 14 for each bacterium that grew on the noted plates. The number of colonies counted on each plate can be found in figure 4(table 3) for the cucumber. Then figure 5 was the bacterial colonies for cucumber in CFU/ml; that grew on the respective plates during the fermentation process and was similar to figure 4.
The figure 6 was the graph of the fermentation process for the cucumber and the respective bacterial counts in CFU/ml (log 10).
The graph showed an increase for the LSD [aerobic], TSA [anaerobic & aerobic] and the WN5 [anaerobic]. In addition, the WN5 [microaerophilic], and EC [aerobic], all basically had a little rise and then declined to 1. 0 *101 from day 2 to 14. Also, the PS just declined to 1. 0 *101 from day 2 to 14. Discussion: Each one of the plates used to measure different environmental factor that were present to us as the fermentation process continue for the fourteen-day process.
Each dish will be described based on the bacteria that each one of the plates selected for and why they were used through the experiment. The TSA agar plates were the control environments, one aerobic and the other anaerobic. In the begin we had 2 aerobic TSA dish one started with an initial dilution of 10-1 while other was 10-3 after the first week these plate were showing the same environment so one was deleted. The TSA plates allow for all the possible bacteria to grow, selecting for all possible types.
Bacteria identification is accomplished in a number of ways. Two common tools microbiologists use to identify unknown bacteria include dichotomous key and biochemical tests. The dichotomous key is useful when a microbiologist only needs to know which group an unknown microbe belongs to on a general level. When a microbiologist needs to identify a specific bacterium, biochemical tests are used. ...
The two WN5 plates were both initial diluted at the same 10-1 factor, the only variation to these dish was the environment that they were placed in anaerobic condition, was achieved by the use of a gas pack in the fermentation jar. The fermentation jar that was set up to mimic the anaerobic condition of the fermentation jar was achieved, by the use of a gas pack fermentation system. The gas pack is used to create an oxygen free environment for the anaerobic microbes. Then gas pack contains sodium borohydride and sodium bicarbonate, which creates an H20 during their reaction. The hydrogen gas combines with the oxygen to make water H2O.
The reaction results in all of the free oxygen being used and the creation of the anaerobe environment, which is similar to the environment in the fermentation jar. The WN5 was for the anaerobic and microaerophilic conditions and had cyclohexane and 5% salt that selects for bacteria and inhibit the grow of yeast and molds no mater what environment it was put in. The PS agar dish had Irgasam ® inhibits the growth of most of the bacteria and will allow the Pseudomonas spp. to grow. The goal of this dish was to measure if any harmful Pseudomonas spp. were growing at the end of the fermentation process, the bacteria was present in the beginning.
At the end day fourteen, the PS agar had no visible growth on the plate and was less than 1. 0 *101 CFU/mL; which was approximately 10 colonies forming units per milliliter. Also, the EC dish inhibited the growth of Gram-positive bacteria and selected for Gram-negative bacteria because it had bile salt. The EC medium selected for the enteric coliforms. Since the EC and PS plate had less than 1. 0 *101 CFU/mL making the cabbage and cucumber safe to eat. Due to time constraints, we unfortunately were not able to try the sauerkraut and the pickle that were produced during the fourteen-day fermentation process.
The LSA plate had TTC (triphenyltetrazolium chloride) and casein, which during a reduction reaction allows for the differentiation of lactobacilli and streptococci, over a range of temperatures and salt concentrations than any other lactic acid bacteria. It produces carbon dioxide and acids which rapidly lower the pH and inhibit the development of undesirable micro-organisms. The carbon dioxide produced replaces the oxygen, making the environment anaerobic and suitable for the growth of subsequent species of lactobacillus. Removal of oxygen also helps to preserve the vegetables and stabilises any ascorbic acid that is present.
The oxygen cycle is the biogeochemical cycle that describes the movement of oxygen within its three main reservoirs: the atmosphere (air), the total content of biological matter within the biosphere (the global sum of all ecosystems), and the lithosphere (Earth’s crust). Failures in the oxygen cycle within the hydrosphere (the combined mass of water found on, under, and over the surface of a ...