Biotechnology, microorganisms and fermentation

In a nutshell

Biotechnology can be used in food and drink production, drug production and bioremediation. This involves using microorganisms such as bacteria and fungi. These microorganisms are cultured in controlled conditions in fermenter vessels where the desirable product can eventually be removed.

Biotechnology

Definition

When living organisms and biological processes are manipulated to produce useful products like food and drugs.

Microorganisms

The living organisms used in biotechnology are mainly microorganisms, such as bacteria and fungi. These microorganisms have many advantages.

1.	The ideal growth conditions of microorganisms can easily be created by adjusting the nutrients, temperature and pH.
2.	Microorganisms have a short life-cycle so they grow quickly and products can be made very rapidly.
3.	Using microorganisms is economical as they can be grown on inexpensive materials.
4.	Microorganisms can be grown at any time of year.

Enzymes

Biotechnology also uses enzymes to make products. These enzymes can be intracellular, meaning they are contained within cells of organisms. Biotechnology also uses isolated enzymes, these are enzymes that aren't contained within cells. Isolated enzymes that are naturally secreted by microorganisms are known as extracellular enzymes.

Extracellular enzymes are cheaper to use because they are naturally secreted. This means they do not have to be extracted from inside the cells like intracellular enzymes.

Industrial processes

Microorganisms can be used in a wide range of industrial processes.

Process	Description
Brewing	In the beer making process, yeast is added to a grain and other ingredients. The yeast then respires anaerobically using glucose from the grain. This leads to the production of ethanol and carbon dioxide. This is known as fermentation.
Baking	Yeast is added to bread to make it rise. This because when yeast ferments sugars, it produces carbon dioxide that causes the dough to rise.
Cheese making	Rennet contains an enzyme known as chymosin that can be used to clot milk. It is therefore used in the cheese making process. Rennet used to be extracted from the stomach of calves, but now yeast cells can be genetically modified to directly produce the chymosin. Curiosity: Fungi are also used to create blue cheeses, they are responsible for the characteristic blue veins on these cheeses.
Yoghurt production	Lactic acid bacteria are used to clot milk and cause it to thicken. These bacteria convert lactose into lactic acid which causes this thickening and creates a sour taste. This process is also done in cheese making.
Penicillin production	Under stressful conditions, Penicillium fungi produce an antibiotic called penicillin. Penicillium does this to prevent bacteria from taking any limited resources. This penicillin can be collected and used in medicine.
Single-cell protein production	Quorn^TM is made from the fungus Fusarium which is grown in aerobic conditions on a glucose syrup food source. The fungal biomass is harvested and then purified to produce the mycoprotein.
Insulin production	Insulin can be made by genetically modified bacteria which have the human insulin gene inserted into their DNA. The insulin is then purified and can be used to treat people with Type $1$ diabetes.
Bioremediation	Bioremediation is the process of using organisms to remove pollutants from contaminated areas. Pollutant removing bacteria can break down pollutants into less harmful products. This cleans up a polluted area.

Using microorganisms in food production

There are many advantages and disadvantages of using microorganisms in food production.

Advantages	Disadvantages
Microorganisms used in food production can be grown on waste products that are by-products of other processes. This reduces overall waste.	A lot of effort is required to prevent contamination as unwanted bacteria poses a serious health hazard to humans.
Microorganisms can be grown easily and quickly, with low production costs compared to other food sources.	People may be opposed to consuming food grown using bacteria and fungi.
Single-cell protein may be considered healthier than animal meat as it contains less saturated fat. It is also a way to tackle food security.	Although single-cell protein is generally healthier than animal meat, if eaten in large quantities it can cause gout due to the high levels of uric acid released when amino acids are broken down.
Microorganisms can be grown anywhere and at any time of the year. Food can be grown in hostile conditions or in low-income countries where malnutrition is especially prevalent.	Single-cell protein does not have the same taste or texture when compared to animal meat. Some people may therefore not want to eat it.

Fermentation vessels

Biotechnology requires microorganisms to be cultured. This means one type of microorganism is grown under controlled conditions. These cultures can be maintained in fermentation vessels.

Biology; Cloning and biotechnology; KS5 Year 12; Biotechnology, microorganisms and fermentation — 1. Waste gas out, 2. Water in, 3. Water out, 4. Nutrients in, 5. Sterile air in, 6. Product, 7. Water jacket, 8. pH probe, 9. Paddles, 10. Culture medium.

The conditions inside a fermenter must be kept constant to ensure optimum growth of microorganisms and maximum yield of desirable products.

Factor	Method of regulation	Reason
pH	Monitored by a pH probe.	Enzyme activity will be affected by extreme pHs.
Temperature	Maintained by a water jacket surrounding the vessel.	Temperatures that are too high will cause enzymes to denature and temperatures too low will prevent them from working.
Nutrient availability	Fresh nutrient medium is circulated around the vessel by paddles.	Microorganisms need nutrients such as carbon, nitrogen, minerals and vitamins to grow.
Oxygen availability	Sterile air is regularly pumped into the vessel.	Most microorganisms respire aerobically.
Sterile vessel	Each vessel is sterilised with superheated air between uses.	This kills any other microorganisms that may compete with those being cultured.
Concentration of product	The product is removed regularly.	If the product is allowed to build up, it may affect the synthesis.