1. ECONOMIC
IMPORTANCE OF
BACTERIA
H A R M F U L & U S E F U L A C T I V I T I E S

3. HARMFUL
ACTIVITIES
PATHOGENIC
ACTIVITIES
FOOD SPOILAGE
CONTAMINATION
OF WATER
DENITRIFICATION
BIOWEAPON

4. USEFU
L
ACTIV
ITIES
SOIL
FERTILI
TY INDUST
RY
CONTRO
L OF
INSECT
S
MEDICI
NE
BIO-
TECHNO
LOGY
BIO-
METALL
URGY
RETTIN
G
POLLUT
ION
CONTRO
L
SEWAG
E
DISPOS
AL

5. HARMFUL ACTIVITIES
1. PLANT PATHOGENIC ACTIVITIES
– Except Corynebacterium all phytopatogenic bacteria are gram-ve
– Diseases in plants
– Blight, Wilt, Leaf spots, Canker, Tumors etc.
– Produce
TOXINS
ENDOTOXINS
Are lipopolysacch.
Present in the cell wall
of gram-ve bacteria
EXOTOXINS
Less common
Are proteins secreted
from bacteria into
surrounding medium

6. • XANTHOMONAS CITRI
CITRUS CANKER
• CORYNEBACTERIUM TRITICI
TUNDU OF WHEAT
• AGROBACTERIUM TUMEFACIENS
CROWN GALL OF SUGAR BEET
• XANTHOMONAS ORYZAE
BLIGHT OF PADDY

7. 2. FOOD SPOILAGE
– Food spoilage can be described as the process by which food quality becomes
compromised and its edibility significantly reduced.
– Numerous signs are indicative of food spoilage and they range from changes in the
ordinary appearance of the foods, changes in its texture, bad odor and poor taste.
– Food- excellent medium for bacterial growth
– Bacteria grow luxuriantly when temperature & humidity are favorable
– Bacteria act on sugars and proteins in food to produce products like ammonia and
alcohol which change the taste, appearance and smell of food by the process called
fermentation.
– Change- flavor, aroma and appearance of food- unsuitable for consumption

8. – While the bacteria itself may or may not be harmful, the waste products
generated by bacteria may be unpleasant to taste or may even be harmful to
one's health.
– There are two types of pathogenic bacteria that target different categories of
food. The first type is called Clostridium botulinum and targets foods such as
meat and poultry, and Bacillus cereus, which targets milk and cream.
– When stored or subjected to unruly conditions, the organisms will begin to
breed apace, releasing harmful toxins that can cause severe illness.

9. 3. WATER CONTAMINATION
– Bacteria multiply in water- unpotable
– Salmonella typhi- Typhoid
– Shiegella dysentriae- Dysentry
– Vibrio cholerae- Cholera

10. 4. DENITRIFICATION
– Nitrates & nitrite ammonia & free nitrogen
– Pseudomonas aeruginosa, E. coli etc.
– Reduce soil fertility

11. 5. BIOWEAPONS
– Toxic substances produced by bacteria and other micro-organisms
that can be used to produce disease and even death in living
organisms.
– Bacteria can produce epidemics in people because they spread easily
and multiply quickly.
– Example: Anthrax can used as a germ bomb to spread disease in
epidemic form.
– Anthrax is an acute disease caused by Bacillus anthracis
– Symptoms- fever, respiratory problems, fatigue, muscle ache, enlarged
lymph nodes, nausea, vomiting and diarrhea

12. Bacillus anthracis

13. USEFUL ACTIVITIES

14. 1. INCREASE SOIL FERTILITY
INCREASE SOIL FERTILITY
NITROGEN
FIXING
BACETRIA
NITRIFYING
BACTERIA
AMMONIFYING
BACTERIA

15. AMMONIFYING BACTERIA
Many saprophytic bacteria hydrolyse proteins of dead plants and animals present in
soil into amino acids and organic nitrogenous bases
Eg. Bacillus mycoides, B. vulgaris, Clostridium etc.
• AMINO ACIDS
AMMONIFYING
BACTERIA
• AMMONIA
AMMONIFICATION
• AMMONIUM
COMPOUNDS
USED BY PLANTS

16. NITRIFYING BACTERIA
NITRIFICATION
AMMONIA OXI. NITRATE
NITROSOMONAS
/ NITROCOCCUS
AMMONIA NITROBACTER
NITRITE
USED BY
PLANTS
NITRATE

17. NITROGEN FIXING BACTERIA
Belong to the
genus
Rhizobium
Occur in root
nodules of
legumes
eg,.
Beijerinkia,
Azospirillum
SYMBIOTIC
Eg.
Azotobacter,
Clostridium
FREE-LIVING

18. 2. INDUSTRY
DAIRY
DEXTRAN PRODUCTION
ACETONE & BUTANOL
VINEGAR
CURING OF TEA & TOBACCO
TANNING OF LEATHER

20. DAIRY INDUSTRY
– Eg. Lactobacillus acidophilus, Streptococcus cremois
– Manufacture of milk products like- butter, cheese, yogurt etc.
– Particularly lactic acid bacteria
COAGULATES
MILK
PROTEIN
LOW pH
LACTIC
ACID
LACTIC
ACID
BACTERIA
LACTOSE
SUGAR IN
MILK

21. DEXTRAN PRODUCTION
– Dextran is a polysaccharide (made of glucose)
produced extracellularly by some lactic acid
bacteria of the genus Leuconostoc &
Streptococcus
– It acts as molecular sieves
– Used medicinally as an antithrombotic to reduce
blood viscosity

22. PRODUCTION OF ACETONE –BUTANOL-ETHANOL
– Acetone–butanol–ethanol (ABE) fermentation is a process that
uses bacterial fermentation to produce acetone, n-Butanol,
and ethanol from carbohydrates such as starch and glucose
– The ABE fermentation produces solvents in a ratio of 3 parts
acetone, 6 parts butanol to 1 part ethanol.
– Clostridium acetobutylicum is the most well-studied and widely
used.
– Although less effective, Clostridium beijerinckii and Clostridium
saccharobutylicum bacterial strains have shown good results as well

24. VINEGAR PRODUCTION
– Acetic acid bacteria (AAB) are a group of Gram-negative bacteria
which oxidize sugars or ethanol and produce acetic acid during fermentation
– All acetic acid bacteria are rod-shaped and obligate aerobes
– Acetic acid bacteria are airborne and are ubiquitous in nature
– Vinegar is produced when acetic acid bacteria act on alcoholic beverages such as
wine
– Vinegar bacteria {acetic acid bacteria (AAB)}, are members of the genus
Acetobacter and characterized by their ability to convert ethyl alcohol (C2 H5
H5 OH) into acetic acid(CH3 COOH) by oxidation

25. ANAEROBIC AEROBIC
GLUCOSE ETHANOL ACETIC ACID (VINEGAR)
Yeast AAB

26. CURING OF TEA AND TOBACCO
– Tea leaves are subjected to
fermentation to attain a
particular flavor and taste. This
process is called curing
– Bacillus megatherium is used
in processing of tea
– Micrococcus candisans is used
used in the curing and
fermentation of tobacco leaves

27. TANNING OF LEATHER
– Hides or skins of animals contain pieces of flesh sticking to them.
Bacteria act on these and remove all traces of flesh. The hides are
treated by a process called tanning to get leather.
– Tanning hide into leather involves a process which permanently
alters the protein structure of skin, making it more durable and less
susceptible to decomposition.
– The process of tanning of leather is carried out with the help of
enzyme protease produced from the bacterium Bacillus subtilis.

28. 3. RETTING OF FIBRES
– Hemp and flax are bound by pectin and tannins which are broken down
by bacteria to obtain individual fibres. This is called retting of fibres that
is a separation of stem and leaf fibre of plants from other softer tissue.
– It is controlled microbial decomposition of pectin without simultaneous
decomposition of fibres
– Retting is actually decomposition activity of certain micro-organisms,
which helps in the separation of plant fibers in jute, flax, hemp etc.
– These bacteria (Clostridium) grow under low oxygen content causing
hydrolysis of the pectic substances that bind the fibers with the main stem.
– These fibers are commonly used in the manufacturing of ropes, canvas,
carpets and other products.

29. 4. POLLUTION CONTROL
– Use of bacteria and other micro-organisms to decay or reduce the concentration
of hazardous waste from a contaminated site – BIOREMEDIATION
– The microbes have been variously modified through genetic engineering to
increase their efficiency of bioremediation
– Eg. GM Pseudomonas aeruginosa is capable of degrading petroleum
hydrocarbons- used to check pollution after oil spillage.
– Other eg. Micrococcus, Candida

31. 5. CONTROL OF INSECTS (BIOLOGICAL CONTROL)
– Many bacteria secrete crystalline proteins which are toxic to
larvae of caterpillars and insects (Lepidoptera), but non-toxic
to plants and animals
– Serve as bioinsecticides
– Some of the bioinsecticides are based on Bacillus thuringiensis
– Bacillus thuringiensis produces a toxin called B.t. toxin, which
which is toxic to several insect larvae, some of which are
common pests to crop plants.
– Similarly the endotoxin produced by Bacillus sphaericus and
Clostridium bifermentans destroys the mosquito larvae.

34. 6. SEWAGE TREATMENT
– Conventional sewage treatment uses
micro-organisms which develop
naturally within the sewage treatment
eg. Streptococci, Bacilli
– In newer approaches sewage is
inoculate with specific micro-
organisms

35. 7. IN MEDICINE
– Bacteria, Fungi and Actinomycetes are important antibiotic producing
organism
– Eg. Streptomyces griseus- Streptomycin, Cycloheximide
– S. erythreus- Erythromycin, Bacillus licheniformis- Bacitracin
– Antibiotic producing microbes have also been genetically modified to
increase antibiotic production or to produce novel/ hybrid antibiotics
– Protoplast fusion is the most common method for this.
– Acremonium chrysogenum + Penicillium spp. = new strain of A. chrysogenum
BACILLUS
CIRCULANS
GENE
TRANSFER
STREPTOMYCES
KANAMYCETICUS
AMIKACIN
(ANTIBIOTIC)

36. 8. IN BIOTECHNOLOGY
– Bacterial cells are transformed (GM) and used in
production of commercially important products
– Eg. GM E.coli cells – production of Insulin, human
growth hormone Somatotrophin ( used to treat pituitary
dwarfism)
– GMO for Production of interferons (antiviral proteins)

37. 9. IN BIOMETALLURGY
Extraction of metals using bacteria
 THESE BACTERIA ARE
USED FOR EXTRACTION
OF COPPER AND
URANIUM FROM
INSOLUBLE MINERALS