16/11/2025
Role of Microbes in Aquaculture
Nitrosomonas spp.
• Role: Ammonia-oxidizing bacteria (AOB) that convert toxic ammonia (NH₃) to nitrite (NO₂⁻) in biofilters and pond systems.
• Benefits in Aquaculture:
o Maintains water quality by reducing ammonia toxicity.
o Essential in RAS (Recirculating Aquaculture Systems) and biofloc setups for nitrification.
o Supports fish/shrimp health and prevents stress-related mortality.
• Application: Often included in nitrifying consortia for pond inoculation or biofilter seeding. Works best at pH 7–8 and 25–30 °C.
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Nitrobacter spp.
• Role: Nitrite-oxidizing bacteria (NOB) that convert nitrite (NO₂⁻) to nitrate (NO₃⁻), completing the nitrification cycle.
• Benefits in Aquaculture:
o Prevents nitrite accumulation, which can cause brown blood disease in fish.
o Stabilizes nitrogen cycle, reducing water exchange needs.
• Application: Used alongside Nitrosomonas in biofilters or pond probiotics. Optimal conditions similar to Nitrosomonas.
Thiobacillus ferrooxidans
• Water quality improvement: Included in FerBac Plus formulations for oxidizing ferrous iron and sulfur in borewell-sourced pond water, reducing hardness and toxicity. Results in stabilized pond ecosystems and improved shrimp moulting and growth.
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Clostridium butyricum
• Gut health: A well-studied probiotic producing butyrate—a short-chain fatty acid that strengthens the colonic barrier and regulates immunity. [vitalibrary.com], [theconversation.com]
• Digestive aid: Alleviates antibiotic-associated diarrhea, IBS, and constipation while promoting beneficial microbes like Lactobacillus and Bifidobacterium. [vitalibrary.com], [theconversation.com]
• Neuromodulation: Butyrate’s anti-inflammatory effects may extend to neuroprotection and mood improvements via the gut-brain axis. [supplement...decode.com], [theconversation.com]
• Growth & health booster: Dietary supplementation in shrimp and fish enhances growth performance, feed conversion, antioxidant capacity, disease resistance, and gut integrity. [europepmc.org], [ija.schola...ticahq.com]
• Immune modulation: In largemouth bass, bolsters antioxidant defense, immune gene expression, and hypoxia tolerance. [frontiersin.org], [ija.schola...ticahq.com]
• Application forms: Suitable as a feed additive or water treatment; dosing around 10⁸–10⁹ CFU/g feed or 50–100 g/acre water. [stbiol.com]
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Rhodococcus spp.
• Metabolic versatility: Degrades organic, solvent-rich, metal-laden pollutants due to diverse enzyme systems. [link.springer.com], [mdpi.com]
• Biotechnological value: Produces biosurfactants, carotenoids, polyhydroxyalkanoates, antimicrobials, siderophores, and nanostructures. [link.springer.com], [nutrition-...idence.com]
• Environmental remediation: Effective in removing heavy metals from soil and water. [frontiersin.org]
• Probiotic & water cleaner: In hatcheries, used for biodegradation of wastes and enhancing survival, yield, and stress resistance in fish such as Pangasius. [teamonebiotech.com], [jetir.org]
• Enzymatic feed improvements: Isolated from fish gut, produces phytase to enhance mineral bioavailability from plant-based feeds. [link.springer.com]
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Rhodobacter spp. (Purple Non-Sulfur Bacteria)
• Water treatment: Purple non-sulfur bacterium (PNSB) that removes COD, nitrates, ammonia, and heavy metals under light/anaerobic or dark/aerobic conditions. [journalcsij.com], [iris.unife.it]
• Biofloc and pond management: Essential in biofloc systems for nutrient cycling, especially nitrogen and sulfur removal, supporting animal health. [link.springer.com], [microbiofarm.com]
• Enhancing shrimp diets: As a protein additive in diets with CoQ10, improves growth, microbiota balance, and stress tolerance in whiteleg shrimp. [frontiersin.org], [e-fas.org]
• Ammonia removal: Rhodobacter azotoformans reduces NH₄⁺ by ~60% in shrimp pond water. [e-fas.org]
Rhodopseudomonas rubrum
• Photosynthetic Bacteria: Purple non-sulfur bacterium capable of anoxygenic photosynthesis, Improves Dissolved Oxygen, effective in carbon fixation, pollutant degradation, bioplastic precursors, and wastewater bioremediation. [mdpi.com], [animalinsight.blog]
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Pseudomonas putida
• Disease resilience: Probiotic feed in Nile tilapia improves growth, feed efficiency, and boosts serum immune markers and disease resistance. [ouci.dntb.gov.ua], [academic.oup.com]
• Infection control: Targeted treatments (e.g., with titanium dioxide nanogel, florfenicol) help manage P. putida-induced infections in tilapia and seabream. [bmcvetres....entral.com], [bohrium.com]
• Robust bioremediator: Degrades diverse pollutants (aromatic hydrocarbons, pesticides, phenolics, crude oil) through metabolic flexibility and engineered acid tolerance for industrial applications. [frontiersin.org], [ejournal.m...anursa.org], [als-journal.com], [journals.asm.org]
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Corynebacterium glutamicum
• Amino acid factory: Industrial-scale producer of L glutamate, L lysine, L threonine, branched-chain amino acids via metabolic engineering, central metabolism optimization, cofactor balancing, and regulatory control. [microbialc...entral.com], [link.springer.com], [mdpi.com], [link.springer.com]
• Circular aquaculture: Engineered in RAS sidestream to produce astaxanthin—a valuable fish feed pigment—reducing waste and boosting feed efficacy. [mdpi.com], [pdfs.seman...cholar.org]
• Fermented feed benefits: Fermenting sea cucumber feed increases protein, fatty acids, antioxidant activity, immune enzyme levels, gut enzyme activity, and suppresses Vibrio. [link.springer.com]
• Single-cell protein trials: Used as fishmeal substitute in grey mullet feed, affecting growth and digestive enzyme activity—highlighting species-specific outcomes. [frontiersin.org]
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Cordyceps sinensis
• Shrimp feed additive: Mycelial polysaccharides enhance growth, immune enzyme activities, and antioxidant status in whiteleg shrimp, while lowering Vibrio counts. [europepmc.org]
• Adaptogen & performance booster: Evidence suggests improved endurance, muscle recovery, immune modulation, antioxidant, and anti-aging activity. [healthline.com], [vitalibrary.com], [verywellhealth.com]
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Trichoderma reesei
• Pathogen control: Aquatic Trichoderma species demonstrate antagonism against Saprolegnia diclina, helping manage fungal infections in salmon egg hatcheries. [mdpi.com]
• Shrimp pond health: Marine T. reesei addition in shrimp farms reduces Vibrio counts, improves water quality parameters, and enhances shrimp growth and survival. [journals.ekb.eg]
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Bacillus amyloliquefaciens
• Algal bloom mitigation: In clay-based formulations, effectively clears harmful algal blooms (e.g., Heterosigma akashiwo) and improves pond health. [frontiersin.org], [doaj.org]
• Nitrogen removal: Isolated strains degrade nitrite and ammonia in aquaculture water, particularly effective under pH ~8 and 30–35 °C. [springerpl...eropen.com], [link.springer.com]
• Feed additive effects: Dietary inclusion in carp increases growth performance, feed conversion, survival, and maintains optimal pond water conditions. [biochemjournal.com], [starbiozyme.com]
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Akkermansia muciniphila
• Emerging aquaculture probiotic: Detected in shrimp gut microbiota—its presence linked to health. [link.springer.com]
• Metabolic benefits in fish:
o Prevents high-fat diet-induced lipid disorders in zebrafish—reducing liver fat, enhancing mitochondrial and gene function, and boosting beneficial microbiota. [doaj.org]
o Improves glucose metabolism in common carp, enhancing insulin-like responses, reducing blood glucose/triglycerides, and modifying microbiota structure. [x-mol.com]
Paracoccus pantotrophus
• Hydrogen sulfide removal: Found in commercial PondDtox® products, it oxidizes toxic H₂S into sulfate in pond sludge, enhancing survival, growth, feed conversion, and reducing odor in shrimp/fish ponds. [bing.com], [thefishsite.com], [msd-animal...alth.co.in]
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Desulfovibrio desulfuricans (SRB)
• Target for control: Produces toxic H₂S in shrimp ponds, causing oxygen depletion and growth issues. Bacteriophage therapies targeting Desulfovibrio show promise, reducing H₂S and increasing dissolved oxygen. [ija.schola...ticahq.com], [jabonline.in]
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Acetobacter xylinum (Komagataeibacter xylinus)
• Aquafeed and water quality enhancement: Though not directly tested in aquaculture, its cellulose production offers potential for biofloc systems, immune-supportive edible films, or feed enhancements. [jstor.org], [en.wikipedia.org]
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Alcaligenes denitrificans
• Algal bloom control & nitrate removal: Kills cyanobacteria like Microcystis, improving water clarity and controls nitrates through denitrification—suitable for HAB prevention and enhanced water quality. [int-res.com], [journals.plos.org]
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Bacillus mesentericus
• General Bacillus benefits: Acts as reliable probiotic—enhances growth, immunity, disease resistance, nutrient cycling, water quality and quorum-quenching in various aquaculture systems. [skretting.com], [link.springer.com], [walshmedic...lmedia.com], [frontiersin.org]
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Bifidobacterium bifidum
• Gut health probiotic: Used in fish/shrimp systems alongside Lactobacillus, it supports digestion, immunity, and water quality in biofloc and RAS setups. [teamonebiotech.com], [link.springer.com]
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Cellulomonas spp.
• Cellulase producers in feed: Present in freshwater systems and fish gut, these microbes produce cellulases to aid plant fiber digestion, improving feed efficiency in fish. [en.wikipedia.org], [link.springer.com]
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Lactobacillus reuteri
• Probiotic feed supplement:
o Enhances growth, digestive enzyme activities, nutrient retention, gut morphology, and encourages tight-junction gene expression in tilapia and bass. [doaj.org], [x-mol.com]
o Produces fish-gut beneficial levan polysaccharides, supporting synbiotic outcomes. [link.springer.com]
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Aspergillus oryzae
• Feed additive benefits:
o As a synbiotic with β-glucan in Nile tilapia, it enhances growth, digestive enzymes, immunity, antioxidant responses, and gut morphology. [link.springer.com], [search.lib...utexas.edu]
o Converts fish-processing wastewater into protein-rich aquafeed via submerged cultivation in sustainable processing systems. [link.springer.com]
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