Second day, October 5th, 2010.
On the second day, Mr. Shaman once again came to demonstrate the preparation of fermenters for autoclaving. Before he came to the laboratory, we prior inoculate one colony of
S. Cerevisiae (Saccharomyces cerevisiae) into the inoculation medium. Then the medium containing inoculate is incubated in shaker at 30°C and 200 rpm for 24 hours.
Figure 1: The area of the workplace is sterilized with Lysol
Figure 2: Scraping up a single colony
Figure 3: The lid of the agar plate is lifted and a single colony is scrapped up using sterilized inoculating loop
Figure 4: The medium is inoculated with the colony on the inoculating loop
Figure 5: The flask is incubated in the incubator shaker
After that, we prepare the fermentation medium using the same formula as the day before, 1% of yeast extract, 2% peptone and 2% galactose. The amount of fermentation medium made is 1.5 l/ fermenter. The fermenter is then loaded with the fermentation medium that has been prepared before hand. After that, the fermenter together with the fermentation medium is autoclaved.
Figure 6: 2% of glucose
Figure 7: 1% of peptone
Figure 8: 1% of yeast extract
Figure 9: 1.5 L of water
Figure 10: The YEPG mixture is dissolved in 1.5 L of distilled water
Figure 11: The medium is mixed using stirrer until all the mixture is properly mixed
Figure 12: The fermentation medium is loaded into the fermenter vessel
Figure 13
Before the pH electrode can be used in the fermentation, it needs to be calibrated first. The silicone that covered the tip of the electrode is removed. The calibration option in the bioreactor instrumentation is set with high calibration point (pH 7). Then, the probe tip is immersed in buffer solution pH 7 until it get a stable reading. After stable reading is achieved, the value of the buffer is entered in Minifors. The electrode is washed and ready for the second calibration. The steps for buffer 4 are similar as the buffer 7 and then confirm the calibration by pressing Enter. Then the electrode is washed and fitted into vessel. When placing the electrode into the vessel, the stirrers need to be switch of to avoid breaking the electrode. The pO2 electrode is fitted the same way as the pH electrode.
Figure 14: pH probe is calibrated before use during fermentation
Figure 15: buffer solution at pH 4.01 is used for the calibration of the pH electrode
Figure 16: Buffer solution at pH 7.01 that is used in calibrating the pH electrode
Saturday, October 16, 2010
the 2nd day @ 12:01 PM 
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