BY4 - Microbiology
- Created by: beth-marie2511
- Created on: 11-06-16 17:06
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- BY4 - Microbiology
- Penicillin
- Fermenter is inoculated with a culture of penicillium notatum which grows under optimum condition in the fermenter
- Takes about 30 hours for penicillin production to begin
- Penicillin is secreted by the fungus and accumulates in the medium
- Delay in production occurs because penicillin is a secondary metabolite
- Serial Dilutions
- A method of counting the number of bacteria in a sample
- Autoclave equipment at 121 degrees for 15-20 minutes
- Place 9cm3 of distilled water into 3 test tubes
- 1cm3 of the bacterial sample is mixed in the first test tube
- 1cm3 of the sample of the first test tube is mixed in the second test tube
- 1cm3 of the sample of the second test tube is mixed in the third test tube
- Transfer 1cm3 of each sample onto a sterile nutrient agar plate
- Repeat this to have 3 plates for each sample
- Use a sterile spreader to spread the sample around the plate
- Incubate at 25 degrees for 24 hours
- Select suitable plates (60-100) colonies with countable colonies and count them
- Calculate the number of bacteria per cm3 of the original sample using a dilution factor
- Inaccuracies of population number can occur if colonies are clumped together
- Penicillin
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