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3.3 describe, using a specific example, the benefits of strain isolation methods used in biotechnology in the 20th century
describe, using a specific example, the benefits of strain isolation methods used in biotechnology in the 20th century
- Strain isolation enabled scientists to find a strain of penicillin in a relatively short time when time was vital. This was because a strain of penicillin had to be found that could be reproduced quickly in large quantities. The penicillin was needed to treat wounded troops in WWII. However it eventually became clear that the type of Penicillium notatum, the penicillin mould first discovered by Fleming, would never give enough of the drug to be useful commercially. Mutations created new strains. One way this was done was to bombard the penicillin with X- Rays. Through strain improvements, improved culture media and better aeration, the yields of penicillin increased from 1-2 units per mL to 25000 units per mL.
- Another way the volume of penicillin was increased, was by a new strain being found accidentally. In 1943, laboratory worker Mary Hunt discovered a new strain of penicillin called Penicillium chrysogenum that grew so well in a tank that it more than doubled the amount of penicillin produced. This, along with deep fermentation and the use of corn steep liquor made the commercial production of penicillin possible in the US in that year.
- Researchers continued to find higher-yielding Penicillium moulds, and also produced higher yielding strains by exposing molds to x-rays or ultraviolet light. Today penicillin is one of the cheapest antibiotics and so is available to most people.