microrganisms in aquacutlure

1. Role of
microrganisms in
aquaculture
By- Harapriya behera

2. What do u mean by
micro-organisms????
Microorganisms (microbes) are those life forms too small to be seen
by the naked eye.
 The term microorganism is thus a functional description rather
than a taxonomic one, and the grouping includes a wide variety of
organisms which may be autotrophs or heterotrophs and may be
harmful or beneficial.
Microorganisms include members of the animal and plant
kingdom,(algae) protozoa, bacteria, and fungi and virus as well.

3. Bacterias:
1. Cellulolytic, ammonifying, ureolytic
2. Amylolytic- conversion of starch- lactic acid
3. Methanogenic.
4. Proteolytic,
5. Nitrogen fixing, nitrifying, denitrifying
6. Phosphate solubilising, phosphatase producing
7. Sulphate reducing, sulphur oxidizing
8. Iron and manganese (oxidizing) etc

4. Fungii:
1. Fungi grow in the form of a finely-branched network of strands
called hyphae- can release digestive enzymes and take up
nutrient.Secrete enzymes can break down cellulose into glucose.
2. Fungi are the only known organisms that degrade lignin
completely. Cellulose and lignin are structural materials in plants
that are difficult to degrade.
3. Ex-ascomycetes and basidiomycetes

5. FungiBacteria

6. Viruses
1. Viruses are very small, ranging 0.01- 0.03 microns, and only
visible by using an electron microscope.
2. They cannot live independently- multiply inside the cells of other
organisms. Their demand for a host is fairly specific.
3. For example: crustacean virus. Viruses are the simplest of all
organisms and are made of nucleic acid (either DNA or RNA)-
coated with a protein layer.

7. Protozoans
1. Prokaryotes: amoeba paramecium volvox etc
• Eubacteria (true bacteria) and
• Archaebacteria (Ancient bacteria)
2. Eukaryotes: rotifers; daphnia, moina and artemia etc. some
termites, anaerobic protozoans in the gut degrade cellulose

8. Virus Protozoa

9. Phytoplankton commonly known as algae:
• Algae (contain chlorophyll) and obtain their energy from the sun
using CO2 by the process called photosynthesis.
• Algae are generally beneficial in aquaculture by supplying oxygen
and as a natural food base for the cultured animals.
• Ex- Blue green algae , Green algae, Golden algae ,Diatoms and
Dinoflagellates

10. Zooplankton
1. Organisms are suspended in the water and are so small that even
slight currents move them about.
2. Most fish fry eat three main types of zooplankton—rotifers,
cope- pods and cladocerans.
3. They may vary in size but they are easily digestible rather than
phytoplankton so they readily taken up by fishes.

11. Phytoplankto
n
Zooplankton

12. Role of micro-organisms
1. Productivity
2. Biogeochemical cycle
3. Decomposition
4. Mineralisation
5. Waste water treatment
6. Bio-remedeation

13. Grazing
GrazingMineralization
Grazing
Uptake
Excretion
andlysis
Uptake
Excretion
and lysis
Excretion
and
lysis
Excretion
and
lysis
Phytoplankton Zooplankton
Bactivorous
zooplanktonBacteria
Dissolved organic
compounds
CO2

14. Productivity.
Blue green algae are primary productivity in the pond ecocystem.
(nostoc, anabaena, spirulina, chlorella, scenedesmus,
cladophora,oscillatoria , trichodesmium)
SCP refers to dried cell of micro organisms grown in large quantiies
for the use of animal and fish feed suppliments. These scps include
algae yeast and fungi. Rich in nutrients. Ex- spirulina protein
powder.
Zooplanktons are primary consumers that feed on phytoplankton in
terms being eaten by fish fries.

15. Ecological pyramid of pond
ecosystem.

16. Biogeochemical cycles
• Carbon, Nitrogen, Phosphorus and Sulphur, cycles are
significantly influenced by bacteria. The important
steps are
Carbon cycle –
• Assimilation
• Dissimilation

17. Carbon cycle

18. Nitrogen cycle
• Fixation:- N2 NH4
• Nitrification:-NH4
+ NO3
-
• Ammonification:-N2 NH3
• Denitrification:- NO3
- N2
• Nitrate ammonification:-NO3
- NH4
+.

20. Nitrogen Fixation:
N2 ---------> NH4
+
By many free-living bacteria such as clostridia, azotobacter and cyanobacteria.
Nitrification
NH4
+ ----------------> NO2
− (nitritation) by AOB
NO2
− ----------------> NO3
− ( nitratation) by NOB
Anaerobic Respiration or Denitrification. Denitrifying bacteria are typically
facultative microbes.
NO3
− ----------------> NO2
−
NO2
− ----------------> N2

21. Phosphorus cycle–
• Solubilisation
• Enzymatic hydrolysis:
Sulphur cycle
• Sulphurication:-
• Desulphurization
• Protein degradation:-

23. H2S----------------> S ----------------> SO4
2

24. Decompsition
• Decomposition otherwise known as biodegradation of organic material
(CH2O) back to CO2 + H2O and H2.The fungi play a significant role in
biodegradation, but the prokaryotes are equally important.
• Decomposition involves the initial degradation of biopolymers (cellulose,
lignin, proteins, polysaccharides) by extracellular enzymes, followed by
oxidation (fermentation or respiration) of the monomeric subunits.

25. • Cellulose is decomposed by aerobic mesophilic bacteria like cytophaga in neutral
and alkaline water and vibrio in acidic waters. Also achromobacter,
pseudomonas, actinomycetes and fungi(aspergillus, chaetonium, curvularia,
fusarium decompose cellulose in pond ecosystem.
• Gram negative spore formers are the first group to colonize the dead organic
matter followed by spore forming gram positive ones.
• Lignins which are practically impossible to degrade are but degraded by fungis.
• The ultimate end products are CO2, H2O and H2, perhaps some NH3 (ammonia)

27. Mineralization
• Chemoautotrophs like Nitrosomonas, Nitrosococcus, and Nitrospira are
resposible for nitritation whereas Nitrobacter, Nitrospira, Nitrococcus-
nitratation.
• Proteolytic bacteria and fungi bring about ammonification.
• Acinetobacter, Alcaligens, Pseudomonas, Enterobacter, Escherichia,
Vibrio, Micrococcus and Bacillus reduce nitrate to elemental nitrogen
through the process of Denitrification.
cont..

28. • Nitrogen fixation is brought about aerobically as well as anaerobically
• Eg: Azotobacter, Azomonas, Clostridium, Desulfovibrio, Achromobacter,
Flavobacterium, Corynebacterium, Spirilum etc
Many enzymes produced by bacteria are capable of mineralizing organic phosphorus
compounds – phosphatase( Psuedomonas, Vibrio, Bacillus, Micrococcus)
• Facultative chemoautotrophs like Ferrobacillus, Gallionella, Leptothrix, Crenothrix,
Clonothrix, Pedomicrobium, Metallogenium, Sidercapsa oxidize ferrous and
manganous ions.
• Facultative anaerobes that reduce nitrate may reduce ferric ion to ferrous ion.
cont…
.

29. • some bacteria and fungi produce phytase, an enzyme which releases
soluble inorganic phosphate (PO4
3−) from organic phytic acid (inositol
hexaphosphate).
• Chromatium and chlorobium are chemoautotrophs responsible for
sulphurication,
• Desulfovibrio, desulfotomaculum and pseudomonas reduce sulphates
aerobically , the process being known as desulphurization
(biodesulphurization).
• Pectins and other humic substances are attacked by mycobacteria.
• The methanogens include methanobacterium, methanococcus, and
methanosarcina.

30. Waste water treatment
1. Biological waste water treatment is used to remove dissolved and
colloidal organic matter in water. (bacteria, protozoa, rotifers, nematodes,
fungi, and algae plays important role in biological treatment.)
2. Certain microorganisms are well known to able to remove metals from
solution by precipitation.(sphaerotilus, leptotrix, gallionella)and by
oxidation thiobacillus.

32. Bioremeadiation
Hydrocarbon oxidizing bacteria, algae and fungi are widely distributed. Most
common gram negative rods –psuedomonas and alcaligens. Other include
micrococcus, cornybacterium, mycobacterium.
Some classes of pesticides like carbamates and herbicides like
carbamothioates and phenoxy alkanoics undergo biodegradation.
• When the organisms get attached to any submerged object say rock or pipe
line they develop a BIOFILM layer over there.

33. Important ascpects of microrganisms
• Generate Oxygen in the Atmosphere.
• Productivity, the nutrition of the cultured animal
• Recycle nutrients stored in organic matter to an inorganic form.
• Fix nitrogen from the Atmosphere into a Useable Form.
• Water quality
• Disease control and environmental impact of the effluent
• Give Plant Roots Access to Nutrients in the Soil.

34. QUESTIONS???