3. Soil as a habitat for Microorganisms:
Soil is an unique habitat for microorganisms
It contains vast population of all groups of microorganisms
Soil contains Organic Matter-Major source of energy for Mio’s
Soil is the region where many biochemical reactions w.r.t.
*degradation of organic matter and
*Nutrient cycle occurs
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Soil is the best habitat for microorganisms
Soil is colonised with immense diversity of microrganims
4. Soil microbiology:
It is a branch of science / Microbiology which deals with the
study of soil microorganisms and their activities in the soil”.
Microbial population in soil: The microbial population in the soil is made up of five
major groups,
1. Bacteria
2. Actinomycetes
3. Fungi [ a) molds (b) yeasts]
4. Algae
5. Protozoa
6. Viruses ??
5. Bacteria
Size:
0.2-1.5 by 3-5 µm
Important Characteristics:
• Prokaryotic
• Unicellular
• Simple Internal structure
• Grow on artificial laboratory media
• Reproduction asexual (mostly simple cell division)
Practical significance:
• Some cause diseases
• Some perform role in natural cycling of elements and increase soil
fertility
• Manufacture of valuable compounds in Industry
6. Fungi (Yeasts)
Size:
5.0-10.0 µm
Important Characteristics:
• Eukaryotic
• Unicellular
•Usually oval, Spherical or cylindrical in shape
• Grow on artificial laboratory media
• Reproduce asexually by budding or via sexual spores
•Aerobic and anaerobic
•Heterotrophic
•Found abundant in acidic & high osmotic conditions
Factors influencing:
pH: 4 to 5 ideal
Moisture:
Aeration: Both aerobic and Anaerobic
Population in soil: 103 CFU/g soil
7. Practical significance:
• Some cause diseases:
• some are used as food supplements
• Manufacture of alcoholic beverages, wine etc.
•Eg: Saccharomyces, Candida, Torula, Rhodotorula, Torulopsis
8.
9. Fungi (Molds)
Size:
2.0-10.0 µm by several mm
Important Characteristics:
• Eukaryotic
• Typically Multicellular
• Many distinctive structural features
• Cultivated on artificial laboratory media
• Reproduction by asexual or sexual spores
Practical significance:
• Decomposition of many materials
• Industrial production of many chemicals like antibiotics
• Can cause diseases
10. Actinomycetes
Size: 0.5-5.0 µm
Important Characteristics:
• Specific group of bacteria
•Have characteristics similar to both bacteria & fungi
•Like Bacteria: Smaller in size and prokaryotic
•Like fungi: cells are elongated and branched, the brances are
called mycelia
•Slow growing, sensitive to acidic pH
•Aerobic , Heterotrophic
Practical significance:
• Produces several antibiotics
•Produces several actives which are used as biopesticides Eg:
Avermectins. Abamectins, Spinosyns
•Play important role in composting (Because of thermotolerance)
Important Genera: Actinomyces, Nocardia & Streptomyces
11. Algae
Size:
1.0 µm to several centimeters
Important Characteristics:
• Eukaryotic (Except BGA)
• Unicellular or Multicellular/ fillamentous
• Photosynthetic (Contain Chlorophyll)
•Require moisture & light for their survival
• Most occur in aquatic environments
• Reproduction asexual or Sexual
•Produce different kinds of pigments
•Diatoms contain silicates (glassy) in cell walls
Practical significance:
• Production of food in aquatic environments
• Source of food and in Pharmaceuticals
• Some produce toxic substances
•Eg: Chroococcus, Oscillatoria, Anabaena, Nostoc, Scytonema, Calothrix
12.
13.
14.
15.
16. Protozoa
Size:2.0-200 µm
Important Characteristics:
• Eukaryotic, Single celled organisms
•Most abundant in-vertebrates & simplest animals
•Lack cell wall
•Similar to animal cells
•Most are motile and are classified
by means of locomotion
(cilia, flagella or pseudopodia)
• Some cultivated on laboratory Media,
while some are intracellular parasites
• The mainly feed on bacteria
• Reproduction asexual or sexual
•Produce cysts
Practical significance:
• Some are pathogenic (malaria
causing -Plasmodium)
Euglenoids: Photosynthetic
AMOEBA
PARAMECIUM
TRYPANOSOMA
17.
18. Viruses
Size:
0.015-0.2 µm
Important Characteristics:
• Do not grow on artificial media
require living cells within which they reproduce
• Obligate parasites
• Electron microscopy required to observe
Practical significance:
• Cause diseases in humans animals plants
• Also infect microorganisms (Bacteriophages and Mycophages)
19.
20. University of Horticultural Sciences Bagalkot,
College of Horticulture, Udyangiri, Navanagar, Bagalkot-587104
ESSENTIAL SERVICE PASS
Name : Chinnapagouda Patil
Designation : Care Taker, Boys Hostel
Chief Warden
