How Does Ph Affect Yeast Fermentation

The vials were placed in the water and the oxygen levels were read every 5 minutes until 30 minutes was reached. As the oxygen levels were collected they were put into a table that had all three tubes labeled at each 5-minute increment. After 30 minutes the experiment was completed and the clean up process could begin.

at that temperature, there was the most amount of catalase activity. On the pH graph, the

6) The tape was used to measure gas accumulation in the balloon after 1minute. Measurement and qualitative observations were recorded.

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

1. Sucrase will have the greatest activity at pH 6 2. Sucrase will have the greatest activity at 40 °C (104 °F) 3. Sucrase activity increases with increasing sucrose concentration until a plateau is reached.

Please Note: This lab involves a lot of waiting for the gas collection. Make sure you allot yourself the full three hours to perform the experiments.

* By using the dropper and measuring cylinder, 7 ml sodium carbonate solution was added to the test tube

Then we inverted the tubes so an air bubble would form in the little tube that is now upside-down. Now that we know what to do, we marked the little tube 2/3 full. One tube was filled to that line with glucose solution, another with fructose solution, sucrose solution and the last one with water. Next, the little tubes were topped off with a yeast solution. Then we slide a big tube over the little one and completed the inversion, this is done for every little test tube. After they are all inverted our group measured the bubble present at the top of the little tube. Then we put all of the inverted test tubes into a hot water bath for 20 minutes. After 20 minutes we took the tubes out and measure the air bubbles in the tubes. Next, we recorded the data calculated the net change from the beginning of the experiment to after the hot

To improve the results from the experiment buffer solutions that were not whole pHs could have been used e.g. pH 4.5, 5.5 etc. This would have provided more reliable results as a wider range of results would have been produced. Using pHs with decimals would also help to more accurately determine the optimum pH as the optimum may have been above or below the pH stated in the hypothesis; 8. In this experiment however the optimum is taken at 8 because the graph does not rise again.

Figure 1: Amount of O2 gas curves to the time at which it was measured according to low, medium, and high pH.

We did this to test which test tube would contain the highest concentration of glucose. What we wanted to know was if the lactase would affect the function of the enzyme. Our hypothesis is the lactase functions within a narrow pH and that will change in pH would affect the function of the enzyme. We predict that if we change the environmental factors it will have an effect the function of the enzyme if the pH is outside the range in its optimum activity. Our hypothesis was then proven because the reaction only occurred in a neutral and acidic state of pH, not basic. Which means the enzymes prime ability to function is a neutral, and acidic pH range.

An unknown sample was massed and put into three test tubes for three different trials. A gas transfer assembly was put together and hydrochloric acid was added to each sample in each test tube. A reaction between the carbonate sample and the acid occurred and the volume of carbon dioxide gas produced was recorded. This process was repeated three times. The mass

When sodium carbonate was added to the separating funnel, effervescence occurred, inferring the release of carbon dioxide gas as a product of the neutralisation reaction. As the process continued, pressure built within the separating funnel, so it was vital to open the tap, after continuously inverting it.

To study the effects of temperature, pH, enzyme concentration, and substrate concentration there were certain steps that were followed in order to conduct this experiment. Each factor had a separate procedure to follow to find how each had a different effect on the enzyme.

2. Following solutions are added to the tubes and the pH of each tube is determined: