Pseudomonas putida

Other Names

Arthrobacter siderocapsulatus Dubinina and Zhdanov 1975Bacillus fluorescens putidus Flügge 1886Bacillus putidus Trevisan 1889Pseudomanas putida (misspelling)Pseudomonas arvilla O. HayaishiPseudomonas barkeri RhodesPseudomonas convexa Chester 1901Pseudomonas cyanogena HammerPseudomonas eisenbergii Migula 1900Pseudomonas incognita Chester 1901Pseudomonas mildenbergii Bergey et al.Pseudomonas ovalis Chester 1901Pseudomonas putida (Trevisan 1889) Migula 1895Pseudomonas rugosa (Wright 1895) Chester 1901Pseudomonas striata Chester 1901

Synopsis

Pseudomonas putida: A Comprehensive Reference

Important Preliminary Note on Classification

Pseudomonas putida is not a botanical ingredient, herbal remedy, or conventional dietary supplement in the established sense of those terms. It is a bacterium of significant scientific and biotechnological interest, and it appears in a very limited number of animal-feed probiotic preparations. It has no documented history of human traditional or medicinal use, no recognized pharmacopeial monograph, and no approved human dietary supplement status from any major regulatory body (FDA, EFSA, WHO). Any article treating it as a mainstream human supplement would be inaccurate. This reference therefore covers what the peer-reviewed literature and authoritative sources actually document: its microbiology, its genuine biotechnological and agricultural roles, the limited animal-based probiotic evidence, and the verified safety and clinical data.

Identity and Classification

Taxonomic Identity

Pseudomonas putida is a Gram-negative, rod-shaped, saprophytic soil bacterium with a versatile metabolism, and it is amenable to genetic manipulation, making it a common organism used in research, bioremediation, and synthesis of chemicals and other compounds.

The genus Pseudomonas belongs to the class γ-Proteobacteria, order Pseudomonadales, and family Pseudomonadaceae. The full taxonomic lineage, as recognized by NCBI Taxonomy, runs: cellular organisms → Bacteria → Pseudomonadati → Pseudomonadota → Gammaproteobacteria → Pseudomonadales → Pseudomonadaceae → Pseudomonas → Pseudomonas putida group.

Based on 16S rRNA analysis, P. putida was taxonomically confirmed to be a Pseudomonas species (sensu stricto) and placed, along with several other species, in the P. putida group, to which it lends its name.

The so-called rRNA group I included P. aeruginosa, P. fluorescens, P. putida, and related species, collectively known as the "true" Pseudomonas or Pseudomonas sensu stricto, and species within this group were found to cluster within the γ-subdivision of the Proteobacteria.

Synonyms and Historical Names

Pseudomonas putida is also known historically under several synonyms, including Pseudomonas ovalis, Pseudomonas arvilla, Arthrobacter siderocapsulatus, Pseudomonas striata, Pseudomonas rugosa, Pseudomonas incognita, Pseudomonas convexa, Pseudomonas eisenbergii, Bacillus putidus, Bacillus fluorescens putidus, and Arthrobacter siderocapsulatus.

Intraspecies Diversity: Strains and Biovars

P. putida is further classified into two biovars: biovar A and biovar B, with approximately 103 strains in biovar A and about nine strains in biovar B. The reference strain most extensively studied is KT2440. P. putida KT2440 is the best-characterized pseudomonad and is the plasmid-free derivative of a toluene-degrading bacterium designated P. putida mt-2; it was also the first host–vector biosafety system for gene cloning in Gram-negative soil bacteria.

The P. putida phylogenetic group is monophyletic and comprises 15 phenotypically closely related species; strains of species in this group are metabolically versatile and have attracted attention for their capability to use many different organic compounds, more recently for the presence of some species in clinical specimens and for their pathogenicity against animals (humans, fishes, insects) or plants.

Natural Sources and Habitat

Pseudomonas putida is a rod-shaped, flagellated, Gram-negative bacterium found in most soil and water habitats where there is oxygen, and it grows optimally at 25–30°C and can be easily isolated.

The exceptional nutritional versatility of the genus means they can use a broad range of compounds as carbon sources, including hazardous environmental contaminants; Pseudomonas putida is a typical example with a broad range of biodegradative abilities that can break down unusual carbon sources, such as toxic organic waste (e.g., petroleum and aromatic hydrocarbons), and thus is important in bioremediation.

P. putida has also been isolated from rhizospheric regions of various plants, indicating its possible application in agriculture as a plant growth-promoting rhizobacterium.

Regulatory and Biosafety Status

The Food and Drug Administration (FDA) has listed P. putida strain KT2440 as Host-vector system safety level 1 certified (HV-1), indicating that it is safe to use without any extra precautions, which is why use of P. putida in many research labs is preferable to some other Pseudomonas species, such as Pseudomonas aeruginosa, which is an opportunistic pathogen.

Traditional and Historical Use

Pseudomonas putida has no documented history of deliberate traditional or folk medicinal use in any recorded healing tradition. Unlike herbal or fungal remedies with centuries of ethnomedical documentation, P. putida was not identified as a distinct microorganism until bacteriology emerged as a formal science in the late nineteenth and early twentieth centuries. Its deliberate application in any human-facing product is an entirely contemporary phenomenon, arising only from modern microbiological and biotechnological research. No WHO monograph, ESCOP monograph, Commission E monograph, Ayurvedic Pharmacopoeia, Traditional Chinese Medicine compendium, or any other historical medicinal authority documents the use of this organism.

Key Constituents and Active Compounds

Overview of Metabolic Capacity

Pseudomonas putida has emerged as a microbial laboratory workhorse, with elaborated techniques for cultivation and genetic manipulation available; beyond that, this bacterium offers several particular advantages with regard to natural product biosynthesis, notably a versatile intrinsic metabolism with diverse enzymatic capacities as well as an outstanding tolerance to xenobiotics.

A genome-scale metabolic reconstruction of P. putida KT2440, designated iJN746, accounts for 746 genes, 950 reactions, and 911 metabolites, and captures biotechnologically relevant pathways including polyhydroxyalkanoate (PHA) synthesis and catabolic pathways of aromatic compounds (e.g., toluene, benzoate, phenylacetate, nicotinate).

Secondary Metabolites

P. putida has been applied as a host organism for the recombinant biosynthesis of natural products, including rhamnolipids, terpenoids, polyketides, and non-ribosomal peptides, as well as other amino acid-derived compounds, with a focus on de novo natural product synthesis from intrinsic building blocks by means of heterologous gene expression and strain engineering.

Very common among pseudomonads is the synthesis of the fluorescent siderophore pyoverdine, which is discussed for different applications such as plant growth promotion; additionally, some P. putida strains are reported to release lipopeptide biosurfactants with antimicrobial properties, namely putisolvins and a viscosin-like peptide.

In particular, pyoverdine (PVD), the primary siderophore produced by Pseudomonas, is a peptidic siderophore containing various amino acids; the Fe-binding moieties in PVD are derived from different metabolites that feed into the pentose-phosphate pathway and the tricarboxylic acid (TCA) cycle, with the catecholate moiety synthesized from chorismate (a precursor to aromatic amino acids) and the hydroxamate moiety synthesized from α-ketoglutarate, a TCA cycle metabolite.

Enzymes of Biotechnological Relevance

Pseudomonas putida produces different mycolytic enzymes, including amylase, chitinase, protease, and lipase. These enzymes are relevant not only in agricultural contexts but have also attracted interest in industrial biotechnology and, speculatively, in animal nutrition, though their role in any human supplement context remains unestablished.

Central Carbon Metabolism

The soil bacterium P. putida KT2440 lacks a functional Embden-Meyerhof-Parnas (EMP) pathway, and glycolysis is known to proceed almost exclusively through the Entner-Doudoroff (ED) route; metabolic flux analysis demonstrated that 90% of consumed sugar was converted into gluconate, entering central carbon metabolism as 6-phosphogluconate and further channeled into the ED pathway.

Pseudomonas has a robust iron uptake metabolism that plays a major role in niche colonization and pathogenesis; accordingly, the iron metabolism has been modelled, including the biosynthetic pathway for pyoverdine (a non-ribosomal peptide acting as siderophore) of P. putida KT2440.

Polyhydroxyalkanoates (PHAs)

Pseudomonas putida is capable of converting styrene oil into the biodegradable plastic PHA, which may be of use in the effective recycling of polystyrene foam, otherwise thought to be non-biodegradable.

Scientific Evidence by Area of Application

1. Bioremediation of Environmental Pollutants

This is the most extensively documented and scientifically supported application of P. putida. Evidence is derived from laboratory studies, field trials, and extensive molecular characterization.

Pseudomonas putida has the ability to degrade and remove toluene and other monocyclic aromatic hydrocarbons, including benzene and xylene; the bacterial degradation of aromatic hydrocarbons normally involves the formation of a diol followed by cleavage of the aromatic ring and formation of a diacid such as cis-cis muconic acid.

Based on 16S rRNA analysis, P. putida may be exploited for bioremediation; for example, it has been shown in the laboratory to function as a soil inoculant to remedy naphthalene-contaminated soils.

The strain Pseudomonas putida BS3701 was isolated from soil contaminated with coke by-product waste and is capable of degrading crude oil and polycyclic aromatic hydrocarbons (PAHs).

P. putida is able to colonize various environments, including soil, water, and the plant rhizosphere, and plays important roles in metabolic activities in the environment; due to strong capabilities in degradation and biotransformation of biogenic and xenobiotic pollutants, pseudomonads have great potential for different biotechnological applications, particularly in the areas of bioremediation and biocatalysis.

Evidence strength: Strong at the laboratory and in-field environmental microbiology level. This is not a human health application. No clinical or human supplementation evidence exists in this domain.

2. Plant Growth Promotion (Agricultural Probiotic)

P. putida occupies a prominent position among plant growth–promoting rhizobacteria (PGPR), a group of microorganisms of utmost interest in agricultural biotechnology for their stimulatory and protective effects on plants; some P. putida strains combine outstanding traits such as phytohormone synthesis, nutrient solubilization, adaptation to different stress conditions, and excellent root colonization ability.

One outstanding species is Pseudomonas putida, which is considered a metabolically versatile rhizobacterium ideal for agricultural applications; P. putida is known to quickly colonize the rhizosphere of plants, outcompeting plant pathogens.

The synergy between three phosphate-solubilizing bacterial (PSB) isolates, including Pseudomonas putida, significantly impacted phosphorus solubilization and potato production.

Pseudomonas putida has also demonstrated potential biocontrol properties as an effective antagonist of plant pathogens such as Pythium aphanidermatum and Fusarium oxysporum f.sp. radicis-lycopersici.

Although numerous strains of this species have shown good performance in field trials, their use in commercial products is still very limited; thus, the opportunities and challenges related to the formulation and application of bioproducts based on these bacteria remain a matter of ongoing research.

Evidence strength: Moderate to strong for soil and agricultural applications, based on multiple laboratory and field studies. Not applicable to human supplementation.

3. Aquaculture Probiotic (Animal Evidence Only)

A small body of peer-reviewed animal research exists examining P. putida as a dietary supplement in fish, representing essentially the only setting in which it has been studied as an intentionally administered nutritional supplement.

One study aimed to assess the effects of a probiotic feed mixture containing Pseudomonas putida, in comparison to a yeast product (Saccharomyces cerevisiae), on the growth, immune response, and protection against Aeromonas hydrophila infection in Nile Tilapia (Oreochromis niloticus); Nile Tilapia were divided into three groups and subjected to a 60-day feeding regimen, with the second group receiving a basal diet mixed with 1 × 10⁷ CFU/g diet of P. putida.

The inclusion of P. putida resulted in enhanced growth performance, improved immune status, and effective control of A. hydrophila infection; the treated groups demonstrated increased serum lysozyme, phagocytic, and nitroblue tetrazolium activities indicative of an improved immune response, displayed enhanced resistance against A. hydrophila infection, and histopathological examination revealed that P. putida significantly augmented the nonspecific immune response in Nile Tilapia.

Both probiotics significantly improved survival rates, growth performance, immune parameters, and resistance against A. hydrophila infection, making P. putida a promising component in aquaculture feed formulations.

Bacillus and Lactobacillus species are among the most studied and recommended probiotics for aquaculture; however, researchers are now looking for other probiotic bacteria that can be used in aquaculture, and in this context, non-lactic acid bacteria (non-LAB), which are mainly host-associated, may have promising effects on fish and shellfish.

Evidence strength: Preliminary. The evidence is limited to a small number of animal studies in fish species. No human or mammalian clinical trials have been conducted. Direct extrapolation to human health is not scientifically supported.

4. Biotechnological Production of Natural Products

P. putida has been applied for recombinant biosynthesis of several valuable natural products; this includes rhamnolipids, terpenoids, polyketides, and non-ribosomal peptides, and other amino acid-derived compounds.

This role is entirely ex vivo — the organism serves as a cellular factory for producing compounds that may themselves have nutritional or pharmaceutical value, but the bacterium itself is not the supplement.

Evidence strength: Well-established at the industrial microbiology and biotechnology level. No direct human supplementation relevance.

5. Proposed Gut Health and Probiotic Effects in Humans

Some commercial supplement discussions have proposed P. putida as a human probiotic. The peer-reviewed literature does not support this. While human clinical trials remain limited, the safety profile of Pseudomonas putida is described as well-documented in food and agricultural contexts; its use as a probiotic is supported by its adaptability and non-pathogenic status, making it a promising candidate for future nutritional applications, but more rigorous clinical studies are necessary to definitively establish its efficacy and health benefits in humans. This statement reflects the most optimistic commercial framing; in practice, no peer-reviewed controlled human trial evaluating P. putida as a human probiotic supplement has been published in the indexed literature.

Body Systems and Health Areas: Research Context

Gastrointestinal system (animal data only): Animal studies in aquaculture species have associated dietary P. putida supplementation with improved nutrient absorption and growth, though no human GI studies exist.
Immune system (animal data only): Probiotic-treated fish groups demonstrated increased serum lysozyme, phagocytic, and nitroblue tetrazolium activities indicative of an improved immune response, and displayed enhanced resistance against A. hydrophila infection; histopathological examination revealed that P. putida significantly augmented the nonspecific immune response in Nile Tilapia.
Environmental detoxification (human-adjacent, not a supplement use): The exceptional nutritional versatility of the genus means P. putida can break down unusual carbon sources such as toxic organic waste including petroleum and aromatic hydrocarbons, making it important in bioremediation.
Agricultural/plant systems: Some P. putida strains combine outstanding traits such as phytohormone synthesis, nutrient solubilization, adaptation to different stress conditions, and excellent root colonization ability.

Dosage Forms and Reported Dosages

There are no established or regulatory-approved human dosages for Pseudomonas putida as a dietary supplement. The following doses appear only in animal study contexts:

Aquaculture (Nile Tilapia): In the Aly et al. (2024) study, the probiotic-treated fish received a basal diet mixed with 1 × 10⁷ CFU/g diet of P. putida over a 60-day feeding regimen.

No human clinical dosing information exists in the peer-reviewed literature for this organism as a supplement.

Safety Considerations

General Biosafety Classification

The FDA has listed P. putida strain KT2440 as Host-vector system safety level 1 certified (HV-1), indicating that it is safe to use without any extra precautions. This classification applies specifically to laboratory research use, not to human ingestion as a supplement.

Opportunistic Pathogen Risk

Despite its general characterization as a low-virulence organism, peer-reviewed clinical literature documents that P. putida is capable of causing infections in humans, particularly in vulnerable populations.

Pseudomonas putida belongs to the fluorescent group of Pseudomonas species, a group of opportunistic pathogens that primarily cause nosocomial infections; few cases of P. putida bacteremia in adult patients have been reported, but a review of 23 previously reported cases confirms its clinical relevance.

Of the clinical backgrounds documented, in all 28 reported cases in one literature review, 24 (85.7%) were immunocompromised; in catheter-related bloodstream infection (CRBSI) cases, devices were removed in almost all cases (92.9%).

The risk of Pseudomonas putida infection should be considered particularly in patients with comorbid disorders causing immunosuppression; patients with Diabetes Mellitus had a higher risk (OR 4.33, CI: 1.11–16.77, P = .03), and in cancer cases, the risk was 3.31 times higher (CI: 1.06–10.32, P = .03).

Unlike P. aeruginosa, which is associated with enteritis, sepsis, and serious skin and soft tissue infections in patients with comorbidities, P. putida generally presents as bacteremia associated with endovascular devices; since the first reports of bacteremia due to P. putida, this opportunistic pathogen has played a major role, causing infections in hospitalized patients with underlying diseases, mainly immunosuppressed, post-surgical, and central venous catheter carriers.

Pseudomonas putida, a member of the fluorescent group of pseudomonads, primarily causes infection in immunosuppressed hosts and patients with invasive medical devices; P. putida has been implicated in outbreaks often traced to contaminated fluid and is a rare cause of clinical infection, but should be considered a pathogen when isolated from pure culture.

It can lead to nosocomial infections, especially in patients who are immunocompromised as well as those with invasive catheter placement; despite clinical data regarding P. putida infection being scarce given the low virulence of this organism, it is important to highlight its potential to cause nosocomial infection in ICU settings and its ability to develop multidrug-resistant strains; P. putida infection may also occur in immunocompetent patients.

Antibiotic Resistance

While P. putida has been considered a pathogen of low virulence and susceptible to multiple antibiotics, in recent years resistant strains have emerged.

The antimicrobial resistance profiles of Pseudomonas putida infection have changed with time; P. putida is a specialized aerobic organism of the fluorescent group of Pseudomonas species, and it can be widely found in inanimate hospital surfaces and moist environments because of its strong tolerance to harsh living conditions.

Contaminated-Solution Outbreaks

Environmental microorganisms of this group have a predilection for humid environments and have been reported in outbreaks from contaminated solutions such as distilled water, disinfectants, and transfusions.

Critical Assessment: Supplement Status and Evidence Gaps

Pseudomonas putida does not meet the criteria typically associated with an established dietary supplement ingredient:

It has no history of traditional human medicinal use in any documented healing tradition.
It has no approved human supplement monograph from any pharmacopeia or regulatory body (FDA, EFSA, EMA, WHO, or equivalent).
No randomized controlled trials (RCTs), systematic reviews, or Cochrane reviews address its use as a human nutritional supplement.
All positive probiotic evidence is restricted to fish (aquaculture) models, with dosing information pertaining only to those contexts.
Peer-reviewed clinical literature documents it as an opportunistic pathogen capable of causing bacteremia, nosocomial infections, and, in the context of rising antibiotic resistance, potentially multi-drug resistant infections — particularly in immunocompromised individuals.

Its FDA HV-1 safety designation applies to its use as a research host for genetic manipulation in laboratory settings, and does not constitute approval or endorsement for human ingestion. The gap between its established roles in environmental microbiology, plant biotechnology, and aquaculture, and its proposed use as a human probiotic supplement is very substantial, and no credible regulatory or scientific body has bridged it.

References

Health Conditions

Health conditions that Pseudomonas putida may help support.

No conditions available.

Body Systems

Body systems that Pseudomonas putida may help support.

No body systems available.