Microorganisms, medicines and bioremediation

Producing penicillin

Penicillin chrysogenum needs relatively high oxygen levels and rich nutrient mediums to grow well
Is also sensitive to pH and temperature
This affects the way its produced commercially
Semi-continuous batch process is used

Process has relatively small fermenters to maintain the high levels of oxygen
The mixture is continually stirred to keep it oxygenated
There is a rich nutrient medium
The growth medium contains a buffer to maintain a pH of 6.5
The bioreactors are maintained at about 25-27C

Making insulin

Insulin was originally extracted from the pancreases of pigs or cattle that had been slaughtered for meat
Meant the supply was erratic because it depended on the demand for meat
Some people were allergic to the animal insulin as it was often impure
For some faiths, using pig products wasn't allowed
The development of GM bacteria to make human insulin REALLY helped from 1970s onwards
The bacteria are grown in a fermener and downstream processing means there's a constant supply of pure human insulin

Bioremediation

Bioremediation = microorganisms used to break down pollutants and contaminants in soil and water
Different approaches:
- Using natural organisms --> many microorganisms break down organic material to produce carbon dioxide and water
  - Soil and water pollutants are often biological so if these natural organisms are supported they'll break down and neutralise many contaminants
  - For example: in an oil spill, nutrients can be added to encourage microbial growth and the oil can be dispersed into smaller particles to give a higher surface area for microbial action
- GM organisms --> GM bacteria to break down or accumulate contaminants which they wouldn't naturally encounter
  - Bacteria have been engineered to remove mercury from water --> aim is to develop filters containing these bacteria to remove the mercury
In most cases, the natural micoorganisms outperform the GM ones

22 - Cloning and biotechnology