Chapter 17: Microorganisms and their Applications in Biotechnology
Not considered as cells - no protoplasm.
Live on host cell.
When they are living on host cell they are considered as living thing.
They do not feed, respire, excrete, grow or reproduce - but; inside a host cell, virus can reproduce or replicate.
Viral diseases and our defence system:
cold, influenza, chickenpox, dengue, haemorrhagic fever, herpes and AIDS.
can only be destroyed by antibodies produced by our WBCs.
Living cells.
Larger than viruses.
Non-motile.
Posses hair like threads called flagella.
Three general types:
Cocci - spherical shaped
Bacilli - rod shaped
Spirilla - spiral shaped
Bacteria can be:
Saprophytic - feeding on decaying organic material.
Parasitic - causing diseases in plants and animals.
Autotrophic - able to manufacture food using energy from the sun or inorganic material.
Live as saprophytes.
Unicellular e.g yeast or multicellular e.g bread mould.
Parasitic fungi live on the living tissue of their hosts.
Decomposers in nature
Decomposers feed on dead and decaying organisms and their faeces.
They secrete enzymes which break down complex organic compounds to simple organic compounds.
They absorb small amount of energy and nutrients; most of the energy is lost as heat and the remaining nutrients are released into surrounding.
Inorganic compounds compounds release gases like CO2, hydrogen sulphide and water vapour.
Help maintain life on earth.
Decomposers in sewage:
Decomposed by saprophytic microorganisms.
Bacteria in sewage secrete an enzyme to digest solid organic matter into soluble harmless substances.
Fermentation
Yoghurt making
By fermenting milk and using lactobacillus bulgaricus (bacteria).
In the absence of O2 bacteria respires anaerobically and converts lactose to lactic acid .
This acid curdles the milk producing yogurt, it can later be flavored or sweetened.
Cheese making
Use both bacteria and fungi.
Lactobacillus is used to ferment milk sugar to lactic acid. The mixture curdles milk protein.
Curdled protein together with the fats in the milk, is removed and acted upon by a mixture of bacteria and fungi to produce cheese.
By different temperatures and different variation of bacteria and fungi different kind of cheese is produced.
Production of alcohol
Yeast is used for brewing.
Yeast is mixed with sugar.
Yeast starts to respire anaerobically to produce alcohol and carbon dioxide from sugar.
Complex substances produced by microorganisms.
Used in treatment of bacterial infections.
Commercial production.
Penicillin production.
eg. bacteria and yeast.
Help produce animal feed and human food.
Fermenters
Designed to keep its inside environment favourable for the desired biological process.
Designed for aerobic and anaerobic processes both.
Important features:
Cooling system
Removal of heat during microbial activities.
aeration system
For proper mixing ad adequate aeration.
Not considered as cells - no protoplasm.
Live on host cell.
When they are living on host cell they are considered as living thing.
They do not feed, respire, excrete, grow or reproduce - but; inside a host cell, virus can reproduce or replicate.
Viral diseases and our defence system:
cold, influenza, chickenpox, dengue, haemorrhagic fever, herpes and AIDS.
can only be destroyed by antibodies produced by our WBCs.
Living cells.
Larger than viruses.
Non-motile.
Posses hair like threads called flagella.
Three general types:
Cocci - spherical shaped
Bacilli - rod shaped
Spirilla - spiral shaped
Bacteria can be:
Saprophytic - feeding on decaying organic material.
Parasitic - causing diseases in plants and animals.
Autotrophic - able to manufacture food using energy from the sun or inorganic material.
Live as saprophytes.
Unicellular e.g yeast or multicellular e.g bread mould.
Parasitic fungi live on the living tissue of their hosts.
Decomposers in nature
Decomposers feed on dead and decaying organisms and their faeces.
They secrete enzymes which break down complex organic compounds to simple organic compounds.
They absorb small amount of energy and nutrients; most of the energy is lost as heat and the remaining nutrients are released into surrounding.
Inorganic compounds compounds release gases like CO2, hydrogen sulphide and water vapour.
Help maintain life on earth.
Decomposers in sewage:
Decomposed by saprophytic microorganisms.
Bacteria in sewage secrete an enzyme to digest solid organic matter into soluble harmless substances.
Fermentation
Yoghurt making
By fermenting milk and using lactobacillus bulgaricus (bacteria).
In the absence of O2 bacteria respires anaerobically and converts lactose to lactic acid .
This acid curdles the milk producing yogurt, it can later be flavored or sweetened.
Cheese making
Use both bacteria and fungi.
Lactobacillus is used to ferment milk sugar to lactic acid. The mixture curdles milk protein.
Curdled protein together with the fats in the milk, is removed and acted upon by a mixture of bacteria and fungi to produce cheese.
By different temperatures and different variation of bacteria and fungi different kind of cheese is produced.
Production of alcohol
Yeast is used for brewing.
Yeast is mixed with sugar.
Yeast starts to respire anaerobically to produce alcohol and carbon dioxide from sugar.
Complex substances produced by microorganisms.
Used in treatment of bacterial infections.
Commercial production.
Penicillin production.
eg. bacteria and yeast.
Help produce animal feed and human food.
Fermenters
Designed to keep its inside environment favourable for the desired biological process.
Designed for aerobic and anaerobic processes both.
Important features:
Cooling system
Removal of heat during microbial activities.
aeration system
For proper mixing ad adequate aeration.
