A presentation done on microorganism types and their action in bio fertilizers.

1. Microorganisms in Bio Fertilizer
B V C M Benaragama

2. What are Bio Fertilizers?
Fertilizers produced biologically, mainly using
microorganisms.

3. Types of MOs used in
manufacturing Bio
fertilizers
1. Rhizobium Bacteria
2. Azotobacter
3. Azospirillum
4. Phosphate Solubilizing
Bacteria (PSB)
5. Blue Green Algae (BGA)

4. Rhizobium Bacteria
Function
Rhizobium have the ability to fix
atmospheric nitrogen which is unavailable for
plants. Rhizobium transform atmospheric
nitrogen into nitrates.
Example
Rhizobium leguminosarum

5. Mechanism
1. Legumes have a symbiotic
relationship with rhizobia (root
nodule bacteria)
2. Rhizobia have the ability to fix
atmospheric nitrogen into nitrates
3. Then those nitrates are available
to the host plant, the legume.

6. Application
s
Rhizobium Species Host Plants
Bradyrhizobium japanicum Soyabean
Rhizobium fredii Soyabean
R. phaseoil Common Bean
R. meliloti Alfalfa
R. trifolii Peas

7. Azotobacter Bacteria
Function
Azotobacter is a free-living nitrogen-
fixing bacterium. Which is used as a
biofertilizer in the cultivation of most crops.
Example
Azotobacter vinelandii

8. Mechanism
1. Biological nitrogen fixation under
free-living conditions .
2. Production of phytohormones like
indole 3-acetic acid gibberrillin-
like substances and cytokinins.
3. Solubilization of insoluble
phosphate.

9. Application
s
Azotobacter fertilizer can be used for
wide range of plants some of them are
given below
Tomato
Rice
Potato
Cotton
Wheat
Lemon
Mango
Kinnaw

10. Azospirillum
Function
● Azospirillum is one of the most widely used free living nitrogen fixing microgrnisms
from the family of Rhodospirilliaceae
● They can be found both in in legume and non legume crops
Example
Azotobacter vinelandii

11. Mechanism
Azospirillum on plants
● Produce of phytohormones,
● Fix of atmospheric nitrogen,
● Reduction of nitrate,
● Enhance of mineral uptake by plant

12. Applications
Bacterial species Used for
A. brasilense,
A. lipoferum,
A. halopraeferens
A. oryzae
Used for biofertilizer,mainly for
cereals
Azospirillum brasilense Fix nitrogen in the presence of low
oxygen level
Azospirillum oryzae Associated with the roots of oryza
sativa

13. Phosphate Solubilizing Bacteria
● Phosphorus is an essential macronutrient for plant
● Phosphate fertilizer is easily precipitated into soluble form
● Phosphate solublizing is activity greater for fungi than bacteria
● This bacteria are beneficial bacterial capable of solublizing inorganic phosphorus
from insoluble compounds
Scientific name -
Bacillus megaterium

14. Mechanism
● Phosphate solubilizing microorganisms
convert insoluble phosphate into soluble
form
● Through the processes of acidification,
by the production of organic acids,
production of acid and alkaline
phosphate
● These organic acid can either dissolve
phosphate as a result of anion exchange

15. Applications
Bacterial species Used for
Bacillus megaterium Used to enhance Cd bioavailability
and plant biomass
B. megaterium Increased the extent of Cd
accumulation
The change of Cd indicated that
inoculation

16. Blue Green Algae
Blue-green algae are actually a type of
bacteria that is known as Cyanobacteria.
Function
● Use the sun's energy to manufacture their own
food through photosynthesis.
● Fix atmospheric nitrogen level
Examples
Nostocales, Spirulina

17. Mechanism
● They have chlorophyll and
phycobiliprotein and can fix carbon by
oxygen-evolution photosynthesis like
plants
● They have Heterocysts cells
● Heterocysts cells provide the anaerobic
(oxygen-free) environment necessary for
the operation of the nitrogen-fixing
enzymes.

18. Applications
Bacterial species Used for
Spirulina As a natural food coloring in gum
and candy
Nostocales To fix nitrogen level, For avoid water
pollution
Anabaena, Nostoc and Oscillatoria produce a great variety of secondary
metabolites.

19. Advantages
1. Improves soil organic matter
2. Improves soil structure and tilth
3. Improves soil water holding
capacity
4. Reduces soil crusting problems
5. Reduces erosion from wind
and water
Disadvantages
1. Not essentially rich in all
nutrients
2. Shorter shelf life
3. Does not adapt as per the
situation

20. Questions?