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1. Explain the control philosophy for pH, temperature and dissolved oxygen as was used in the fermentation process.
Control philosophy of:
pH- The pH of the fermentor must be at 7.5 in order for the cells to survive. The pH at this stage is only slightly basic (alkali). The pH of the medium is regulated by the pH pump. The pH pump is attached to an acid and an alkali. The acid used is sulphuric acid while the alkali used is sodium hydroxide. The pH pump would pump in acid if the pH of the medium is higher than the input pH in the system. Similarly, the pH pump would pump in base if the pH of the medium is lower than the desired pH.
Temperature- One very important parameter that affects the final quality of the product. It has an impact on the enzyme activity and growth of various strains of microbial cultures used in fermentation. The temperature of the medium is measured by the temperature probe. If the temperature of the medium is higher than the temperature input in the system, the cooling jacket would cool the system to the desired temperature.
Dissolved oxygen- The dissolved oxygen in the fermentor is measured by the dissolved oxygen probe. Similarly, if the dissolved oxygen in the medium does not correspond to the dissolved oxygen input in the system, the sparger would be activated to release more air into the medium or to lower its volume of released air depending on the desired dissolved oxygen input.
2. Describe the principle of the spectrophotometer which was used to determine the cell density(OD600). Why was 600m used?
Spectrophotometer is quantitative study of the reflection or the transmission properties of a substance as a function of the wave length.
The spectrophotometer consist of 2 devices- Spectrometer that produces any light of any selected wavelength Photometer that measures the intensity of the light.
1. The spectrometer will produce the light of the desired wavelength that passes through the tube to reach the other side where the photometer awaits to receive the intensity of the light. 2. Upon receiving, the photometer will send a voltage signal to a display device normal a galvanometer. The amount of light absorbed is proportional to the voltage signal given by the photometer so therefore in this process, the concentration of the substance in the solution can be measured by calculating the amount of of absorbed light at the appropriate wavelength
The reason why 600nm is used is because it is the maximum absorption of light of the solute.
3. Is GFP a primary or secondary metabolite? At which phase should the product be harvested? At which phase was the product actually harvested?
GFP is a secondary metabolite.
The product should be produced in the late exponential growth phase.
The product was actually harvested after the death phase.
4. Which are some advantages of using a computer control system? From the history chart (which will be given to you after the fermentation process), comment of the effectiveness of the computer control.
Advantages include:
* The computer control system can be auto-controlled.
- pH - p02 set point - stirred speed - temperature
* It is able to monitor the conditions and make sure it is maintained in the desired condition
* To do so, it will automatically change the 4 parameters above when the need to do so arises.For example, if the pH input in the computer does not correspond to the pH of the fermentor, the control system would add in the acid/base needed to make the pH of the fermentor to be similar the pH input in the computer. The same principle applies to the other parameters as mentioned in the first point.
* The computer control system does not require us to be at the site of fermentation.
* It is relatively easy and user-friendly
* By measuring the 4 parameters as mentioned, the computer control system is able to plot a graph that includes all the four parameters in different colours for clear observations.
Based on the history chart which were given, the computer control system is very effective in terms of:
1. Accuracy.
2. Ability of the control system to measure even the slightest change in any one of the parameter.
3. Aiding us to differentiate all the four parameters that were plotted with each other by the 4 respective different colours present.
4. Ability to measure the 4 parameters accurately for nearly 24 hours.
5. Plotting a graph with all the 4 parameters present making it easier for us to obtain the measurement of all the parameters at a desired time.
Control philosophy of:
pH- The pH of the fermentor must be at 7.5 in order for the cells to survive. The pH at this stage is only slightly basic (alkali). The pH of the medium is regulated by the pH pump. The pH pump is attached to an acid and an alkali. The acid used is sulphuric acid while the alkali used is sodium hydroxide. The pH pump would pump in acid if the pH of the medium is higher than the input pH in the system. Similarly, the pH pump would pump in base if the pH of the medium is lower than the desired pH.
Temperature- One very important parameter that affects the final quality of the product. It has an impact on the enzyme activity and growth of various strains of microbial cultures used in fermentation. The temperature of the medium is measured by the temperature probe. If the temperature of the medium is higher than the temperature input in the system, the cooling jacket would cool the system to the desired temperature.
Dissolved oxygen- The dissolved oxygen in the fermentor is measured by the dissolved oxygen probe. Similarly, if the dissolved oxygen in the medium does not correspond to the dissolved oxygen input in the system, the sparger would be activated to release more air into the medium or to lower its volume of released air depending on the desired dissolved oxygen input.
2. Describe the principle of the spectrophotometer which was used to determine the cell density(OD600). Why was 600m used?
Spectrophotometer is quantitative study of the reflection or the transmission properties of a substance as a function of the wave length.
The spectrophotometer consist of 2 devices- Spectrometer that produces any light of any selected wavelength Photometer that measures the intensity of the light.
1. The spectrometer will produce the light of the desired wavelength that passes through the tube to reach the other side where the photometer awaits to receive the intensity of the light. 2. Upon receiving, the photometer will send a voltage signal to a display device normal a galvanometer. The amount of light absorbed is proportional to the voltage signal given by the photometer so therefore in this process, the concentration of the substance in the solution can be measured by calculating the amount of of absorbed light at the appropriate wavelength
The reason why 600nm is used is because it is the maximum absorption of light of the solute.
3. Is GFP a primary or secondary metabolite? At which phase should the product be harvested? At which phase was the product actually harvested?
GFP is a secondary metabolite.
The product should be produced in the late exponential growth phase.
The product was actually harvested after the death phase.
4. Which are some advantages of using a computer control system? From the history chart (which will be given to you after the fermentation process), comment of the effectiveness of the computer control.
Advantages include:
* The computer control system can be auto-controlled.
- pH - p02 set point - stirred speed - temperature
* It is able to monitor the conditions and make sure it is maintained in the desired condition
* To do so, it will automatically change the 4 parameters above when the need to do so arises.For example, if the pH input in the computer does not correspond to the pH of the fermentor, the control system would add in the acid/base needed to make the pH of the fermentor to be similar the pH input in the computer. The same principle applies to the other parameters as mentioned in the first point.
* The computer control system does not require us to be at the site of fermentation.
* It is relatively easy and user-friendly
* By measuring the 4 parameters as mentioned, the computer control system is able to plot a graph that includes all the four parameters in different colours for clear observations.
Based on the history chart which were given, the computer control system is very effective in terms of:
1. Accuracy.
2. Ability of the control system to measure even the slightest change in any one of the parameter.
3. Aiding us to differentiate all the four parameters that were plotted with each other by the 4 respective different colours present.
4. Ability to measure the 4 parameters accurately for nearly 24 hours.
5. Plotting a graph with all the 4 parameters present making it easier for us to obtain the measurement of all the parameters at a desired time.
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