3. What is Microbiology?
• Micro - too small to be seen with the naked eye
• Bio - life
• logy - study
4. Bacteria - what comes to mind?
• Diseases
• Infections
• Epidemics
• Food Spoilage
• Only 1% of all known bacteria cause human diseases
• About 4% of all known bacteria cause plant diseases
• 95% of known bacteria are non-pathogens
5. Beneficial Use of Bacteria
1.Primary decomposers (Decay & decomposition of
Dead Organic matter)–
Several Saprophytic Bacteria are found in soil. They bring
about decomposition of organic matter and change it into
simpler and inorganic substances.
6. 2. Soil fertility
Bacteria play an important role in maintaining the soil fertility
(i). By Nitrogen fixing bacteria
free living- Azotobacter & Clostridium
Symbiotic- Rhizobium
(ii). Nitrifying Bacteria- Nitrosomonas
(convert nitrogen to nitrite)
Nitrobacter (convert nitrite to nitrates)
7. 3.Industrial importance
(i). Acid production
Bacterium Mycoderma aceti converts solution into vinegar.
(ii)Fibre retting
Clostridium butyricum helps in separating the fibres in jute and sun
hemp.
(iii)Curing of tobacco and tea
Micrococcus candescence - peculiar flavour and taste of tea leaves this
process is called curing.Bacillus megaterium flavour and test to
tobacco leaves.
(iv)Dairy industry -Streptococcus lactis help in converting milk into
curd. Lactobacillus casei , Bacillus acidophilus & Lactobacillus plantarum
are also used in dairy industry.
8. 4.Importance of bacteria in medicines
(i)Antibiotics-
Streptomycin (Streptomyces griseus)
Neomycin (Streptomyces Fradiae)
Chloro tetracycline (Streptomycin Venezuela )
Oxytetracycline (Streptomyces rimosus)
Erythromycin(Bacillus subtilis)
(ii) Serum and vaccines vaccine serum developing immunity
in human beings serum is used for treating and controlling
disease like diphtheria. Ammonia vaccines are utilised for
checking disease like typhoid, smallpox, Cholera.
9. 5. Bacteria synthesize chemicals that
our body needs, but cannot synthesize
• Example: E. coli
• B vitamins - for metabolism
• Vitamin K - blood clotting
• Escherichia coli
• Dr. Escherich
• Colon (intestine)
10. 6. Insect Pest Control
• Using bacteria to control the growth of insects
• Bacillus thuringiensis
• caterpillars
• bollworms
• corn borers
11. 7. Bioremediation
• Using microbes to clean up pollutants and toxic
wastes
• Exxon Valdez - 1989
• Genera:-
• Pseudomonas sp.
• Bacillus sp.
12. 8. Recombinant DNA Technology
Gene Therapy
Genetic Engineering
• Bacteria can be manipulated to produce enzymes and
proteins they normally would not produce
• Insulin
• Human Growth Hormone
• Interferon
13. 9. Microbes form the basis of the
food chain
• Marine and fresh water microorganisms
14. HARMFUL USE OF BACTERIA
1.Reduction of soil fertility
Some denitrifying bacteria suggest bacillus denitrificans and
Thiobacillus denitrificans act upon ammonia and some other
compound in soil and release free nitrogen into the
atmosphere this amount for the loss of nutritious
material from the soil which result in reducing soil
fertility also.
15. 2.food poisoning
Several saprophytic bacteria grow on food materials and
produce harmful toxins micrococcus bio-genes cause
poisonous poisoning of cream milk, cheese and meat
products Salmonella typhimurium
and Clostridium botulinum make food poisonous.