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Importances of Photosynthesis Bacteria in Pond Management and Health Performances in Aquaculture

Published on: 3/10/2022
Author/s : Dr. Prakash Chandra Behera / General Manager (Aqua), PVS Group.
Introduction:
The aquaculture industry is rapidly growing and is now considered a major contributor in the global food production. To meet the global demand, aquaculture production practices have been intensified to a greater extent both in technological and practical measures. Aquaculture generates considerable amount of wastes, consisting of metabolic by-products, residual food, fecal matters and residues of prophylactic and therapeutic inputs, leading to the deterioration of water quality and disease outbreaks. Due to fast expansion of aqua culture and the use of more modern farming technologies that involve higher usage of inputs such as water, feeds, fertilizers and chemicals. As a result, aquaculture is now considered as a potential polluter of the aquatic environment and a cause of degradation of wetland areas.
Waste Production in Aquaculture
The physical, chemical and biological conditions of the culture environment have an influence on the health and productivity of shrimp. Exposure of shrimps to toxins like hydrogen sulphide, ammonia and carbon dioxide lead to stress and ultimately disease. There are differences in quality and quantity of components depending on the species cultured and the culture practices adopted. The wastes in hatcheries or aquaculture farms can be categorized as: (1) residual food and fecal matter (2) metabolic by-products (3) residues of biocides and biostats (4) fertilizer derived wastes (5) wastes produced during molting (6) collapsing algal blooms.
Bioremediation in Aquaculture
The current approach to improving water quality in aquaculture is the application of microbes/enzymes to the ponds, known as ‘bioremediation’. When macro and microorganisms and/or their products are used as additives to improve water quality, they are referred to as bioremediators or bioremediating agents.
A successful bioremediation involves: 
  • Optimizing nitrification rates to keep low ammonia concentration.
  • Optimising denitrification rates to eliminate excess nitrogen from ponds as nitrogen gas.
  • Maximizing sulphide oxidation to reduce accumulation of hydrogen sulphide.
  • Maximizing carbon mineralization to carbon dioxide to minimize sludge accumulation.
  • Maximizing primary productivity that stimulates shrimp production and also secondary crops.
  • Maintaining a diverse and stable pond community where undesirable species do not become dominant.
Photosynthetic Bacteria (PSB)
PSB (Photosynthetic bacteria) are a special and unique class of microorganisms that has the ability to convert light energy into chemical energy using their light-absorbing pigments and reaction centers. These bacteria contain a compound known as bacteriochlorophyll which works similarly as chlorophyll in plants and enables them to perform the process of photosynthesis. There are mainly three types of photosynthetic bacteria: Chlorobiacae, Chromatiacae, and Rhodospirillacae.
Classification of Photosynthetic Bacteria
Cyanobacteria perform photosynthesis using water as an electron donor in a similar manner to plants. This results in the production of oxygen and is known as Oxygenic photosynthesis. They contain light-harvesting pigments, absorb carbon dioxide, and release oxygen. Cyanobacteria or Cyanophyta are the only form of oxygenic photosynthetic bacteria known to date.
Bacteria that contain bacteriochlorophyll do not use water as an electron donor. This is known as Anoxygenic photosynthesis. Anoxygenic photosynthetic bacteria consume carbon dioxide but do not release oxygen. These include Green and Purple bacteria as well as Filamentous Anoxygenic Phototrophs (FAPs), Phototrophic Acidobacteria and Phototrophic Heliobacteria.
Chlorobiacae bacteria are green bacteria and also sulphur bacteria that perform anoxygenic photosynthesis. It works as an obligate photoautotroph and uses reduced sulphur species as electron donors. Rhodospirillacae is purple bacteria in rod-shape, whose length can vary. Hydrogen gas is used as an electron donor by these purple bacteria and can also use malate or succinate. There is another purple microorganism known as Chromatiacae which are short gram-negative rods. These bacteria use sulphide and sulphur as their electron donor.
The species currently used in aquaculture are Rhodopseudomonas pastries, Rubrivivax gelatinosa, Rhodobacter capsulata, R. spaheroides, Phaeospirillum fulvum, etc.
Importances of Photosynthesis Bacteria in Pond Management and Health Performances in Aquaculture - Image 1
Role of Photosynthetic Bacteria (PSB) in Pond Management
Disease Controlling Agents
Most probiotics proposed as biological control agents in aquaculture and suppressed the activity of Vibrio harveyi with increasing the survival rate. Photosynthetic bacteria also suppress the pathogenic vibrio like Vibrio harveyi, Vibrio parahaemolyticus and Vibrio splendens and reduce the opportunistic invasion of these pathogens in shrimps.
Decomposes Organic Detritus/ Waste
The dissolved and suspended organic matter contains mainly carbon chains and is highly available to microbes and algae. A good bioremediator (Photosynthetic bacteria) are capable of effectively clearing carbonaceous wastes from water and suitable for bioremediation of organic detritus. Photosynthetic bacteria produce a variety of enzymes that break down proteins and starch to small molecules, which are then taken up as energy sources by other organisms. The removal of Reduction of Nitrogenous Compounds
Bacteriological nitrification is the most practical method for the removal of ammonia from closed aquaculture systems. There are also some heterotrophic nitrifies that produce only low levels of nitrite and nitrate and often use organic sources of nitrogen rather than ammonia or nitrite.
Reduction of Hydrogen Sulphide level
In aerobic conditions, organic sulphur decomposes to sulphide, which in turn get oxidized to sulphate. Sulphate is highly soluble in water and so gradually disperses from sediments. Sulphide oxidation is mediated by microorganisms in the sediment by purely chemical processes. Under anaerobic conditions, sulphate may be used in place of oxygen in microbial metabolism. This process leads to the production of hydrogen sulphide gas.
The photosynthetic benthic bacteria that break H2S at pond bottom have been widely used in aquaculture to maintain a favorable environment. These bacteria contain bacteriochlorophyll that absorb light (blue to infrared spectrum, depending on type of bacterio-chlorophyll) and perform photosynthesis under anaerobic conditions.
Importances of Photosynthesis Bacteria in Pond Management and Health Performances in Aquaculture - Image 2
Functions and Benefits of Photosynthetic Bacteria in Aquaculture
Photosynthesis Bacteria (PSB) helps in the health management of the aquaculture and benefits the aquatic life like shrimps or fish. It also helps degrade organic waste and keeps the pond bottom clean. The bacterial cell wall of these bacteria is more digestible. Also, vitamins, proteins, biological cofactors and carotenoids are found in abundance in these bacteria. Photosynthesis Bacteria (PSB) have multiple effects such as improve water quality, prevent diseases and increases growth rate, all the same time. Photosynthesis Bacteria (PSB) can help to maintain pond in better condition and can increase level of production.
Photosynthetic bacteria are currently being used in various applications which include water purification, bio-fertilizers, animal feed and bioremediation etc. They are used in the treatment of polluted water for reduction of toxic substances in aquaculture ponds such as H2S.
  • The beneficial organisms (Photosynthetic bacteria) create several environmental factors during application and discourage the growth of many harmful or undesirable species of microorganisms.
  • Photosynthetic bacteria utilizes visible light from the sun thereby increasing in population.
  • Photosynthetic bacteria help the production of metabolic by-products, increased biomass population of plankton and algae, production of anti-pathogenic substances and control of the population of pathogenic organisms.
  • Photosynthetic bacteria breakdown organic matter thereby releasing complex compounds such amino acids for utilization by plants.
  • Photosynthetic bacteria generally improve the water quality of aquaculture systems and  inhibit the pathogens in water there by increasing production of the target culture
  • Restrains the overgrowth of algae to keep the water clear and clean
  • Degrades organic substance (Sludge) in form of black mud in the pond bottom.
  • Reduces level of toxic gasses such as ammonia nitrogen, nitrite and hydrogen sulfide to eliminate all kinds of odor in the sludge, while reducing the sludge amount.
  • Photosynthetic bacteria reduces the chemical and antibiotic usage as it prevents aquatic life from disease.
  • Photosynthetic bacteria decrease COD, SS (suspended substances) and BOD and improve water quality.
  • It helps to increase plankton growth with standard water coloration.
Importances of Photosynthesis Bacteria in Pond Management and Health Performances in Aquaculture - Image 3
Benefits as Feed Additives Photosynthetic Bacteria (PSB) for Shrimp/ Fishes
Conclusion
The photosynthesis bacteria helps for use in aquaculture to clean up the pond bottom, maintain good water quality and improve shrimp health in aquaculture. The role of beneficial bacteria to control pathogens will become particularly important in aquaculture. The photosynthesis bacteria use as bioremediators will gradually increase and the success of aquaculture.
Use of probiotics is an effective alternative sustainable source of beneficial microbes with bactericidal or bacteriostatic effect on pathogenic bacteria. The photosynthesis bacteria acts as immunomodulatory capabilities of promoting health status with improving the growth performance & augment the immune system in fishes / shrimps.
  • Photosynthetic bacteria is rich in nutrition as it contains vitamin B, vitamin A, vitamin D, protein and others.
  • Photosynthetic bacteria improve the appetite of fish/shrimps and their digestion.
•    Photosynthetic bacteria stimulates fast growth rate & enhances the survival rate
•    Photosynthetic bacteria enhances immunity & prevents diseases
•    Photosynthetic bacteria improves on production level.
•   Photosynthetic bacteria increases the population growth rate of live food like plankton
     Sources.
Conclusion
The photosynthesis bacteria helps for use in aquaculture to clean up the pond bottom, maintain good water quality and improve shrimp health in aquaculture. The role of beneficial bacteria to control pathogens will become particularly important in aquaculture. The photosynthesis bacteria use as bioremediators will gradually increase and the success of aquaculture.
Use of probiotics is an effective alternative sustainable source of beneficial microbes with bactericidal or bacteriostatic effect on pathogenic bacteria. The photosynthesis bacteria acts as immunomodulatory capabilities of promoting health status with improving the growth performance & augment the immune system in fishes/shrimps.
 
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