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
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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 ¼ 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.
In this lab, the purpose was to determine the stability of a substance after adding an acid or a base. The results claim that liver and buffer are the most resistance to change in pH. Looking at figure 3, buffer and liver both maintain a stable pH even with the addition of an acid or base. However, potato and water have less buffer in them since their pHs did change. In figure 3, the potato acid’s pH level decreased by two, and the potato base’s pH level increased by two. The level of pH of a water acid decreased by 4, while the water base’s pH increased by 5. These results all tie to the fact that buffer is a substance that maintains a stable pH; the presence of buffer in organisms help maintain homeostasis by binding or releasing hydrogen
An unknown bacterium was handed out by Dr. Honer. The appropriate tests were prepared and applied. The first procedure that was done was the gram stain. Under a microscope, if the gram stain is purple, the bacterium is gram positive, if the stain is red, it is gram negative. The next test was the fermentation tests for glucose, sucrose and
There are many substances that can be manipulated and cause the rate of reaction in fermentation to either speed up or slow down. Substances that alter the rate of the reaction could be temperature of the water, the yeast concentration, pH, and the glucose concentration. In the experimental group of the experiment the amount of yeast concentration was manipulated. The objective of this experiment was to determine what factors affect the rate of the fermentation. To test this objective we changed the amount of yeast being used. A higher yeast concentration replaced the controlled yeast amount. A prediction made by my group was that higher amount of yeast would speed up the process of fermentation. Our null hypothesis is there will be no
Purpose/Hypothesis: The purpose of this experiment is to use both cabbage juice and pH paper to determine the pH of household items. This way, we can tell which products are basic and which one are acidic. If we use cabbage juice as an universal pH indicator by comparing it to pH paper then pH determined by the cabbage juice will be unstable because by using cabbage juice, it can be different depending on how diluted it is.
PH can affect the way fermentation occurs due to the irregularity of the acidity or alkalinity within the glucose solution. This is an enzyme-based reaction that is susceptible to pH. The aim of this experiment was to determine how pH affects the yeast fermentation rate by performing the experiment numerous times with a different pH of glucose solution which included pH 3, 5, 7, 9, 11. The hypothesis was ‘If the pH is lower than the neutral point then the fermentation reaction will occur faster?’ The experiment conducted was to measure the amount of C02 produced by the yeast going into fermentation, however varying the pH of glucose solution by using different pHs . To test this every 5 minutes the volume of gas in the test tube was observed and recorded until a period of 30 minutes had been. The end results
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,
The first result of importance was the result of the Gram stain. The observations of the unknown bacteria from the slant culture after Gram staining showed that the unknown bacteria were Gram negative bacilli (Image 1). After determining the unknown bacteria was Gram negative, an oxidase test was conducted on a sample from the slant culture. The cotton swap with the sample of bacteria did not change color when the oxidase reagent was applied, thus providing a negative result. With a negative oxidase test, further tests were conducted to determine various characteristics of the unknown bacteria. A MR-VP broth was inoculated with a sample from a slant culture of unknown bacteria. After incubation, the methyl red reagent was added to the broth, and the broth turned red, providing a positive result (Image 2). An EMB agar streak plate was inoculated with a sample from a slant culture of the unknown bacteria, and after incubation, growth was found on the plate, providing a positive result (Image 3). A Citrate agar slant was inoculated, and after incubation, growth was found on the media, providing a positive result (Image 4). A Urea agar slant was inoculated, and after incubation, the agar had changed from a peach color to a bright pink color, providing a positive result (Image 5). Using the flowchart (Figure 1) developed from the Table of Expected Results, the lab partners started at the oxidase test. Given the negative result of the oxidase test, the flowchart is
The purpose of this lab was to identify two unknown bacteria cultures using various differential tests. The identification of these unknown cultures was accomplished by separating and differentiating possible
Abstract: During this lab, the pH of water in soil from a man made garden, a deciduous forest, and a river bank were tested after leaving it in containers for one, two, and three hours, coming out to a total of three trials with three different soils all together. After testing the pH of the water when being added to the soil for the desired amount of time and comparing it to the original water with no soil added, is then when each pH difference was observed and recorded in a a notebook, while pictures were taken of the experiment being conducted.
Table 2: Consists of color extract taken from a red cabbage for a natural indicator. The pH reading that was measured by using the pH meter and the result of the pH reading to determine whether the solution was acidic or basic.
The intention of this experiment is to determine the effects of pH on the rate of photosynthesis in living leaves. Photosynthesis is a process by which plants convert light energy captured from the sun into chemical energy which they use to perform various plant functions. During the photosynthesis process, light, carbon dioxide, and water react to produce products: sugar and oxygen. The equation for photosynthesis is:
The experiment was carried out to determine if the malic acid or apple acidity is affected by their ripeness. It is hypothesized that the acidity level of the apple fruit would reduce as the fruit ripens. The experiment was performed by squeezing out the juices from the apple fruit and measuring the juice of the apple with a pH probe. The outcome of the experiment was that the unripe fruits had a high acidic level. The content of malic acid decreases from the unripe fruits until the maturity and the fruit pH fluctuates as it ripens. The pH of the unripe apple was 3.2, with the ripe apple, the pH was 3.9 and with the apples that had time to ripen in the laboratory the pH level was 4.5.
Abstract – Yogurt is a product of lactic acid and lactose. In order to produce yogurt, milk is pasteurized (at 45 degrees Celsius) and the inoculum is added followed by incubation. Over a period of 7 days, yoghurt fermentation was attempted using lactobacillus cultures. A liter of milk was supplied and plain yoghurt was used as a starter culture as it contains the necessary bacteria to ferment lactose and produce lactic acid. The milk was added to a flask: then boiled, cooled and inoculated. The milk was incubated for a week and all the while the milk was tested for changes in pH, density, mass and physical changes. The values obtained were then used to determine the growth kinetics of Lactobacillus bulgaricus.
In reference to Figure 1, the results indicated that the liquid medium created through the juice of strawberries resulted in the highest rates of fermentation. However, while initially at the 5, 10, and 15 minute marks, the rate of fermentation of strawberries was the lowest out of all of the liquid mediums; from the 15 minute mark to the 20 minute mark, the height of the bubbles rapidly increased. The second highest rate of fermentation was from the water, which was used as a constant in the experiment. After the water, it was the grape juice that had the next greatest rate of fermentation, subsequently proceeded by oranges, and then lemons which had the lowest rates of fermentation. Each of the rates of fermentation was determined by looking at the height of the bubbles, in the last 5 minute interval, the 20 minute mark of the lab.
The selected potent isolates were inoculated to the seeding medium containing 1% malt extract, 1% peptone 2% glycerol and were incubated at 28 ˚C in shaking incubator (220 rpm) for 48 hours. After termination of the incubation, the seeded cultures were inoculated to the optimized production medium. After incubation for 5 days at 28˚C, the aliquots of filtrate-fermented broth were extracted with ethyl acetate twice (1:1 v/v). The ethyl acetate layers were evaporated and the crude extracts were kept for the subsequent experiments (Seidel,