Biotechnology & genetic engineering
Biotechnology is defined as the exploitation of biological processes for industrial and other purposes, especially the genetic manipulation of microorganisms for the production of antibiotics, hormones, etc.
Genetic engineering is defined as the deliberate modification of the characteristics of an organism by manipulating its genetic material.
Examples of genetic engineering:
- Insertion of human genes into bacteria for the production of insulin
- Insertion of genes into crop plants to confer resistance to herbicides
- Insertion of genes into crop plants to confer resistance to insect pests
- Insertion of genes into crop plants to provide additional vitamins
Anaerobic respiration of yeast
The anaerobic respiration of yeast can be used for various industrial processes such as biofuel production and bread making.
Ethanol used for biofuels
- Yeast is added to a source of sugar and kept in warm conditions.
- In the absence of oxygen, ethanol is produced via anaerobic respiration
- Ethanol can then be used as biofuels
Bread-making
- Yeast is activated by mixing it with sugar and water
- The mixture is then added to flour to form dough
- Dough is left in a warm place to rise
- The dough rises due to trapped carbon dioxide (a product of anaerobic respiration)
- Appropriate temperature must be maintained as enzymes control respiration
- When the bread is fully cooked, high temperatures kill the active yeast and the ethanol evaporates
Fruit juice production
Pectinase is an enzyme that breaks down pectin – A protein found within plant cell walls.
Pectinase is used commercially to break down pectin within fruit cell walls in order to allow easier extraction of juice from the fruit.
Biological washing powders
Biological washing powders are washing washing powders that contain enzymes (mainly proteases & lipases) in order to break down organic substances.
Hot water must be used with washing powders so it is important that the containing enzymes have a high optimum temperature – otherwise they would just become denatured.
The enzymes are often obtained from thermophillic bacteria found in hot springs, and have a optimum temperature of 70 degrees celcius.
Lactose-free milk
For people that are lactose intolerant, it is important to produce lactose-free milk. Lactase is the enzyme that breaks down lactose.
Milk is passed down a series of fixed, immobile beads of lactase which digest the lactose to produce lactose-free milk.
The immobile set-up of the enzymes are advantageous for various reasons:
- Enzymes can be conserved as they do not become dissolved
- Separation of the product from the enzyme is easy since the enzymes are attached on the surface, and do not get mixed with the end product
Penicillin production
Penicillin is an antibiotic made by a fungus called penicillium. A fermenter is used to mass produce penicillin.
Sugars, ammonium salt, and penicillium is added to the fermenter.
- Sugar is for respiration
- Ammonium is for protein and nucleic acid production
Here are some features about fermenters that you must be aware of:
- Monitors pH and temperatures
- Air provides oxygen for respiration
- Has cooling mechanisms to maintain an optimum temperature of approximately 24 degrees celcius
- Stirrer keeps the contents suspended
Bacterial production of human protein
Useful human proteins such as insulin (for management of type 1 diabetes) can be made by bacteria. This is an example of genetic engineering. 
Here are the important steps of this process that you need to be aware of:
- Human cells with human insulin genes are selected
- Chromosomes from those cells are extracted
- Insulin gene from the chromosome is removed via an enzyme called restriction endonuclease enzyme
- A suitable bacterial cell is selected
- Bacteria have loose DNA called plasmids
- Plasmid is removed from the bacteria
- Plasmids are cut open via the same restriction endonuclease enzyme used to cut out the insulin gene from the human chromosome
- Human insulin gene is inserted into plasmids via ligase enzymes
- Plasmids are returned back to the bacterial cell
- The bacteria is left in a fermenter to reproduce
- Rapid aexual reproduction produces a huge colony of bacteria that all have the human insulin gene, and hence produces insulin
- The insulin can be extracted from the fermenter and used to treat diabetic patients