What is Biotechnology?

Biotechnology is a knowledge that is based on Biology. In this technology different living organisms (yeast/bacteria) are used with different technologies (fermenters) to produce many products that make our life on this planet, healthy, easy and comfortable.

Food Biotechnology:

Biological/metabolic process is required to convert organic molecule (glucose) into acid, gas or alcohol in the presence or absence of oxygen. This process is called fermentation. Yeast is a single cell fungus used in this process of fermentation.

Yeast uses sugar as a source of food and when it respires ethanol and carbon dioxide is used (energy released)

The process of fermentation produces three products:

    • Lactic acid: is used for making yoghurt
    • Carbon dioxide: is used for making bread (anaerobic respiration of yeast)
    • Alcohol: is used for making beer (anaerobic respiration of yeast)

  What is the role of yeast in the production of bread?

Bread making is consist of three steps:

    • Kneading: flour, water, salt, sugar and yeast are mixed together thoroughly by folding and stretching either by hand or any machine and make a dough. The protein named gluten is present in flour gives the dough a sticky, plastic texture which holds the carbon dioxide bubbles.
    • Fermentation: dough is placed in warm temperature (27°C) for 2-3 hours. During this time anaerobic respiration occurs in yeast and carbon dioxide and alcohol is produced. Rise of the dough is because of the production of carbon dioxide that trapped in it.
    • Baking: dough is baked at high temperature. This process expands carbon dioxide through the dough that make it rise and soft. High temperature kills the yeast and evaporates the small amount of alcohol that produced. Above all, high temperature hardens the outermost cover that maintain its shape.

In this whole process of bread making, anaerobic respiration occurs, ethanol, a useful product produces and carbon dioxide is considered as a waste product.

  What is the role of yeast in the production of alcohol?

    • Soak the seeds in water and allow them to germinate for 2-3 days.
    • Roast the germinated seeds and grinding them thoroughly.
    • Add hot water in the grinded seeds. It will produce WORT.
    • Now add yeast that feeds on glucose and in return gives alcohol.
    • As the yeast respires, it produces carbon dioxide as well. It produces from that medium and make a foam layer on the top of wort. It creates anaerobic conditions.

Yeast cells (fermentation) —> alcohol + carbon dioxide

What is the role of bacteria in the production of yoghurt?

    • Bacteria used to make yoghurt is known as yoghurt culture or seed. And the purpose of using this in milk is to convert lactose to lactic acid.
    • Bacteria named lactobacillus bulgaricus and streptococcus thermophiles are used to produce yoghurt from milk.
    • Streptococcus thermophiles is an aerobic bacterium that absorbs the oxygen and produce anaerobic condition.
    • First of all, milk will be pasteurized. It means milk will boil for 30 minutes at 60° C.
    • Then let it cool at room temperature.
    • Lactobacillilus bacteria will be used as seed. A small amount of culture of bacteria is added which increases the number of bacteria due to reproduction (binary fission). This small amount of culture also imparts flavor and texture to yoghurt.
    • Lactobacillus bulgaricus produces an enzyme (lactase) which converts milk sugar (lactase sugar) into lactic acid. It drops pH of the milk which causes the milk protein solidifies.
    • The curdled milk is called yoghurt.

Industrial Biotechnology:


A fermenter is a vat or container made up of non-corrosive material (stainless steel) for fermentation. Large number of bacteria and fungi are grown in these containers.

fermenter schematic

An industrial Fermenter

These fermenters can be used for many biological processes for example to produce:

    • genetically modified bacteria
    • penicillin mold to form antibiotic (penicillin)
    • Single cell protein.

The big and important benefit to use the fermenter is to control all the conditions carefully to produce the large amount of desired product.

Following are the suitable conditions that should be maintained while using the fermenter to get a good amount of product:


Working or functions of different parts of an industrial fermenter used for the large-scale production of antibiotics by microorganisms:

industrial fermenter

    • Cooling jacket: During fermentation heat is released (exothermic reaction) which can increase the temperature of the culture. Higher temperature can affect the enzyme activity and protein can be denatured, so the temperature is controlled with the help of water jacket.
    • Impellers/stirring paddles: Mix the content present in the fermenter thoroughly. These stirring paddles or impellers are connected with the motor so these can move continuously.
    • Air spargers: it allows the air to pass through the content easily, thoroughly and evenly.
    • Inlet: used for adding the required nutrients and starter culture.
    • Outlet: harvest/ product is collected through it.
    • Biosensors/probe: used to monitor pH, temperature and pressure. These biosensors are also connected with computer or data loggers to take more accurate readings to keep a strict check on the process.

A large-scale manufacture of antibiotics (penicillin)

    • What is an antibiotic?

Antibiotics are the matters produced by bacteria or fungi which can kill other microorganisms, especially bacteria.

    • What are the negative aspects for using the antibiotic frequently?

Frequent use of antibiotic even for low intensity of infection as well as use of broad spectrum antibiotics cause bacteria to become resistant.  Bacteria can be mutate by which some resistant genes are produced that cause resistance against specific antibiotics. Some patients also use antibiotics every now and then and do not complete their antibiotic course as prescribed for specific period of time by their doctors.It also cause the death of some beneficial and useful bacteria in body, e.g. E.coli bacteria in intestine that produces vitamin K and B12.

    • Describe a large-scale manufacture of antibiotics (penicillin).

Penicillin is a well-known antibiotic produced by a fungus, penicillium. Some of the hyphae of this fungus are inoculated in a culture medium containing a good supply of nutrients for the growth of this fungus. When enough hyphae of this fungus is produced then this amount is poured into a fermenter for large scale production of antibiotic.

    • The culture medium should be sterilized to avoid any type of contamination.
    • This medium also contains glucose for respiration and amino acid for the growth of fungus.
    • In a fermenter, oxygen or air is supplied through a sieve at the bottom containing a bacteria free filter. All the other vents of the fermenter also contain such filters to prevent the entry of any bacteria from air.
    • As the fungi grow, waste products also produced. A vent is there to get rid of nitrogenous waste gases and carbon dioxide gases from the fermenter.
    • Temperature and pH is also controlled so the enzymes can do well because enzymes activity suffers if bacteria do not get appropriate and optimum temperature and pH. Water jacket around the fermenter is also present which also help to maintain the temperature of the medium.
    • When enough growth of penicillium occurs, penicillin is also secreted in culture medium.
    • Fungi are harvested by the process of centrifugation and antibiotic penicillin is extracted and purified from the culture medium.