Environmental Bacteria Research Articles

Unveiling Emerging Opportunistic Fish Pathogens in Aquaculture: A Comprehensive Seasonal Study of Microbial Composition in Mediterranean Fish Hatcheries

The importance of microbial communities in fish hatcheries for fish health and welfare has been recognized, with several studies mapping these communities during healthy rearing conditions and disease outbreaks. In this study, we analyzed the bacteriome of the live feeds, such as microalgae, rotifers, and Artemia, used in fish hatcheries that produce Mediterranean species. Our goal was to provide baseline information about their structure, emphasizing in environmental putative fish pathogenic bacteria. We conducted 16S rRNA amplicon Novaseq sequencing for our analysis, and we inferred 46,745 taxonomically annotated ASVs. Results showed that incoming environmental water plays a significant role in the presence of important taxa that constitute presumptive pathogens. Bio-statistical analyses revealed a relatively stable bacteriome among seasonal samplings for every hatchery but a diverse bacteriome between sampling stations and a distinct core bacteriome for each hatchery. Analysis of putative opportunistic fish pathogenic genera revealed some co-occurrence correlation events and a high average relative abundance of Vibrio, Tenacibaculum, and Photobacterium genera in live feeds, reaching a grand mean average of up to 7.3% for the hatchery of the Hellenic Center of Marine Research (HCMR), 12% for Hatchery A, and 11.5% for Hatchery B. Mapping the bacteriome in live feeds is pivotal for understanding the marine environment and distinct aquaculture practices and can guide improvements in hatchery management, enhancing fish health and sustainability in the Mediterranean region.

Improvement Schemes for Bacteria in MICP: A Review

Biomineralization is a common phenomenon in nature, and the use of microbial-induced calcium carbonate precipitation (MICP) technology for engineering construction is a successful attempt to utilize natural biological phenomena, which has become a hot topic of current research. There are many factors affecting MICP, such as bacterial properties and external environmental factors. Many scholars have carried out a lot of research on these factors, but even under appropriate conditions, the MICP process still has the problem of low efficiency. According to different engineering, the tolerance and effect of bacteria in different environments are also different. At the same time, the cultivation and preservation of bacteria will also consume a large amount of raw materials, which is far more significant than the cost of engineering construction. The efficiency and cost limit the large-scale application of this technology in practical engineering. In response to these problems, researchers are exploring new ways to improve the efficiency of MICP technology. Based on the bacteria used in MICP, this paper explores the mechanism of bacteria in the process of MICP and reviews the improvement of bacteria from the perspective of efficiency improvement and economy.

Degradation of extracellular antibiotic resistance genes using peracetic acid (PAA) and performic acid (PFA)

Antibiotic resistant bacteria (ARB) associated infections are identified as a major threat to human health in the 21st century. Wastewater contains antibiotic resistance determinants and they are discharged to aquatic environments with treated or untreated effluents. These antibiotic resistance determinants can be taken up by environmental bacteria via horizontal gene transfer (HGT) and they can become antibiotic resistant. Among antibiotic resistance determinants, extracellular DNA containing antibiotic resistance genes can be up taken by environmental bacteria via natural transformation. Therefore, we evaluated the suitability of low-cost disinfectants peracetic acid (PAA) and performic acid (PFA) on inactivating total and functional extracellular ARGs in ultrapure water and secondary wastewater effluent matrices using pUC19 as a model ARG. Performance of PAA and PFA in inactivating extracellular ARGs was compared with the performance of free chlorine disinfection. RT-qPCR results showed that inactivation of ampR gene in pUC19 plasmid suspended in ultrapure water and wastewater secondary effluent by free chlorine was higher compared to PAA and PFA. However, the reduction of functional pUC19 by PAA and PFA were comparable to free chlorine. Transformation frequency of pUC19 treated by PAA and PFA achieved the maximum possible reduction within a shorter time compared to free chlorine treatment, highlighting the possibility of having disinfection chambers with smaller footprints in wastewater treatment plants. These results suggest the suitability of PAA and PFA for inactivation of ARGs in aquatic samples as alternative disinfectants to free chlorine.

Super Astragalus polysaccharide in specific gut microbiota metabolism alleviates chronic unpredictable mild stress-induced cognitive deficits mice

Chronic stress affects intestinal microbiota. Astragaloside IV (AS), called super Astragalus polysaccharide, is a monomer component of traditional herbs Astragalus membranaceus which belongs to medicinal food homology (MFH), exerts a neuroprotection effect, but the underlying mechanism has not yet been elucidated. Intestinal flora is also involved in the biotransformation of the active ingredients of MFH species, thus affecting their physiological and pharmacological properties. In this study, we found that AS improved CUMS-induced cognitive impairment, inhibited neuroinflammation, and restored intestinal barrier damage, but the improvement was suppressed by the elimination of gut microbiota, suggesting a key regulatory role for the microbiota. The results of 16S rDNA sequencing showed that AS treatment significantly increased the relative abundance of Lactobacillus reuteri (L. reuteri) and Bacteroides acidifaciens. Furthermore, supplementation of L. reuteri rather than Lactobacillus plantarum restored the effect of AS-supplied dysbiosis mice via inhibition of inflammatory repose and the maintenance of the intestinal epithelial barrier, indicating that dietary AS requires L. reuteri to ameliorate cognitive injury. These findings provide evidence for new therapeutic strategies to treat chronic stress and support the role of specific bacteria in the intestinal environment that metabolizes the AS.

Bacteriophages and Bacterial Resistance: The Link

Bacterial resistance is a public health problem that has caused the most deaths in the world; Various international organizations have launched an emergency call for attention to this problem. One of the main factors that contribute to its appearance is the inappropriate use of antibiotics, which generates the appearance of bacteria with specific genes that shield them from exposure to these drugs. In nature there are elements such as bacteriophages that have the ability to "steal" these genes from inside bacteria and transport them to other bacteria in different environments; In addition, due to their propagation, they are considered one of the links that contribute the most to the dissemination of genes, causing public and veterinary health problems as well as economic losses in different sectors such as agriculture and agriculture.

The Role of Reactive Oxygen Species from Heavy Metal: Effect on reactivity of Fish and Defensive Mechanism of Antibiotic Resistant Bacteria in Aquatic Environment

The Role of Reactive Oxygen Species from Heavy Metal: Effect on reactivity of Fish and Defensive Mechanism of Antibiotic Resistant Bacteria in Aquatic Environment

Bakteriofagi jako czynniki biokontroli populacji niepożądanych bakterii

Bacteriophages as biocontrol agents of undesirable bacteria populations Bacteriophages, i.e. viruses that attack bacteria, are the largest group of biological life forms on Earth. Every species of bacteria has one or more bacteriophages, which act as a natural regulator of their population in environment. The specific way in which phages interact with bacteria makes them a promising alternative to antibacterial chemicals in controlling pathogenic and unwanted bacteria, including biofilm-producing strains or antibiotic-resistant ones. The ability of bacteriophages to control bacterial populations has led to their use in medicine, veterinary medicine, agriculture, aquaculture, wastewater treatment, the food industry, and as bioindicators of microbiological pollution. A promising solution could be the use of bacteriophages to eliminate pathogenic bacteria in the occupational environment, which would reduce the risk posed by harmful biological agents.

Sequencing-guided re-estimation and promotion of cultivability for environmental bacteria

The low cultivability of environmental bacteria has been widely acknowledged, but most previous estimates focused on the proportion of cultivable cells rather than cultivable taxa. Here, we estimate the proportions of cultivable cells and cultivable taxa for two sample types (soil and activated sludge) using cell counting, 16S rRNA gene amplicon sequencing, metagenomics, and cultivation on agar plates under various conditions. We find that the proportion of cultivable taxa exceeds that of cultivable cells at the sample level. A large proportion of cultivable taxa are taxonomically novel but tend to be present at very low abundance on agar plates, forming microcolonies, and some of them cease to grow during subculture. Compared with uncultivable taxa (under the conditions used in our study), cultivatable taxa tend to display higher metabolic activity as inferred by measuring rRNA copies per cell. Finally, we use the generated taxonomic and genomic information as a guide to isolate a strain representing a yet-uncultured class within the Bacteroidota and to enhance the cultivable diversity of Burkholderiales from activated sludge.

Organic geochemical and compound specific stable carbon isotope analyses of n-alkanes and saturated carboxylic acids extracted from late Paleozoic coals

AbstractIsotopic studies of coal organic matter are often conducted to gain information about past ecosystems and plant communities e.g. under changing climate conditions. While many studies focused on isotope analysis of bulk coal organic matter or extractable aliphatic hydrocarbons, the polar fraction and compounds that are bound to kerogen and not freely extractable have received less attention. The aim of this study was to provide a systematic comparison and evaluation of information gained from different molecular compounds (n-alkanes, n-carboxylic acids) extracted from Paleozoic coals before and after alkaline hydrolysis. Stable carbon isotope analysis of these compounds were used to evaluate a possible application of extractable and ‘bound’ lipids for paleoenvironmental analyses. Coal samples of different stratigraphic age, low thermal maturity (VRr < 1.02%, mostly VRr < 0.8%) and from different paleogeographic locations were selected to investigate organic matter deposited under different paleoenvironmental and paleoclimatic conditions. Molecular distributions show prominent carbon preference suggesting preservation of biologic signatures in coal organic matter. Permian Gondwana coals show similar n-alkane and n-carboxylic acid distribution which may be related to Glossopteris flora. Molecular distributions of Carboniferous coal from Europe are more variable with unimodal or bimodal patterns and maxima in the short- or long-chain range, reflecting higher diversity of paleovegetation and different contribution from algae or bacteria in limnic and paralic environments. The isotope signals of free as well as bound fatty acids show closer response for different depositional environments, whereas signals of paraffins and bulk organic matter are less variable. However, averaged fatty acid isotope signals in coals from different paleovegetational realms, e.g. Euramerica and Gondwana differed only marginally. Graphical abstract

Mechanism of bacterial predation via ixotrophy.

Ixotrophy is a contact-dependent predatory strategy of filamentous bacteria in aquatic environments for which the molecular mechanism remains unknown. We show that predator-prey contact can be established by gliding motility or extracellular assemblages we call "grappling hooks." Cryo-electron microscopy identified the grappling hooks as heptamers of a type IX secretion system substrate. After close predator-prey contact is established, cryo-electron tomography and functional assays showed that puncturing by a type VI secretion system mediated killing. Single-cell analyses with stable isotope-labeled prey revealed that prey components are taken up by the attacker. Depending on nutrient availability, insertion sequence elements toggle the activity of ixotrophy. A marine metagenomic time series shows coupled dynamics of ixotrophic bacteria and prey. We found that the mechanism of ixotrophy involves multiple cellular machineries, is conserved, and may shape microbial populations in the environment.

Metagenomic analysis of sedimentary archives reveals ‘historical’ antibiotic resistance genes diversity increased over recent decades in the environment

Abstract Antibiotic Resistance Genes (ARGs) are widespread in freshwater environments and represent a concealed threat to public health and aquatic eco-system safety. To date, only a limited number of studies have investigated the historical distribution of ARGs and their hosts through the analysis of freshwater sedimentary archives. This research gap constrains our comprehensive of the mechanisms underlying natural bacterial resistance formation during pre-antibiotic era (prior to the 1940s) and the development of human-induced bacterial resistance in post-antibiotic era (since the 1940s). In this study, we examined the vertical distribution patterns of ARGs and their associated hosts within a sedimentary core from a eutrophic lake, employing shotgun sequencing methodology. The findings revealed a marked increase in ARG diversity during post-antibiotic era, and the predominant ARG types identified included those conferring resistance to multidrug, bacitracin, macrolide–lincosamide–streptogramin, beta-lactam, tetracycline, fluoroquinolone, glycopeptide and aminoglycoside, collectively accounting for 78.3%–85.6% of total ARG abundance. A total of 127 ARG subtypes were identified in samples, and 48 ARG subtypes shared across vertical sediment resistome profile with two of them, bacA and bcrA, occurring only in post-antibiotic era. Further, 137 metagenome-assembled genomes (83 species belonging to 12 phyla) were identified as ARG hosts, mainly belonging to the phyla Proteobacteria, Nitrospirota, Chloroflexota, Bacteroidota, Actinobacteriota, Cyanobacteria, and Firmicutes. Significant correlation was found between the diversity of ARG and the concentrations of organic matter and heavy metals, suggesting a common source of contamination. Aside the fact that human-induced eutrophication is a forcing factor acting in parallel to increase ARGs releases in water systems, both being indicators of increased urbanization in the catchment, eutrophication may significantly increase bacterial activity, thereby facilitating the spread of antibiotic-resistant bacteria in environment. This study reveals the marked increased in ARG diversity with the onset of antibiotic use by human societies with potential impact of aquatic ecosystem.

Plastic Polymers and Antibiotic Resistance in an Antarctic Environment (Ross Sea): Are We Revealing the Tip of an Iceberg?

Microbial colonization of plastic polymers in Antarctic environments is an under-investigated issue. While several studies are documenting the spread of plastic pollution in the Ross Sea, whether the formation of a plastisphere (namely the complex microbial assemblage colonizing plastics) may favor the spread of antibiotic-resistant bacteria (ARB) in this marine environment is unknown yet. A colonization experiment was performed in this ecosystem, aiming at exploring the potential role of plastic polymers as a reservoir of antibiotic resistance. To this end, the biofilm-producing activity and the antibiotic susceptibility profiles of bacterial strains isolated from biofilms colonizing submerged polyvinylchloride and polyethylene panels were screened. The colonization experiment was carried out at two different sites of the Ross Sea, namely Road Bay and Tethys Bay. Most of bacterial isolates were able to produce biofilm; several multidrug resistances were detected in the bacterial members of biofilms associated to PVC and PE (also named as the plastisphere), as well as in the bacterial strains isolated from the surrounding water. The lowest percentage of ARB was found in the PE-associated plastisphere from the not-impacted (control) Punta Stocchino station, whereas the highest one was detected in the PVC-associated plastisphere from the Tethys Bay station. However, no selective enrichment of ARB in relation to the study sites or to either type of plastic material was observed, suggesting that resistance to antibiotics was a generalized widespread phenomenon. Resistance against to all the three classes of antibiotics assayed in this study (i.e., cell wall antibiotics, nucleic acids, and protein synthesis inhibitors) was observed. The high percentage of bacterial isolates showing resistance in remote environments like Antarctic ones, suffering increasing anthropic pressure, points out an emerging threat with a potential pathogenic risk that needs further deepening studies.

Burkholderia pseudomallei produces 2-alkylquinolone derivatives important for host virulence and competition with bacteria that employ naphthoquinones for aerobic respiration.

Melioidosis is caused by Burkholderia pseudomallei, an opportunistic Gram-negative pathogen that inhabits soil and water in tropical and subtropical regions. B. pseudomallei infections often occur following contact with contaminated water or soil or by inhalation of contaminated dust and water droplets. There is limited knowledge about how B. pseudomallei is able to survive in harsh environmental conditions and compete with the microbes that inhabit these niches. Previous research demonstrated that 3-methyl-2-alkylquinolones (MAQs), and their corresponding N-oxides (MAQNOs), are produced by B. pseudomallei and provide a competitive advantage when grown in the presence of Gram-positive bacteria. In this study, 39 Gram-negative environmental bacteria in the Pseudomonadota and Bacteroidota phyla were isolated and characterized. Intriguingly, B. pseudomallei inhibited 71% of bacteria in the phylum Bacteroidota in zone of inhibition and coculture competition assays, but no Pseudomonadota isolates were similarly inhibited. Transposon mutagenesis was utilized to identify B. pseudomallei genes required for the inhibition of Sphingobacterium sp. ST4, a representative member of the Bacteroidota. Three mutations mapped to hmqA-G, the locus encoding 2-alkylquinolone derivatives, and two mutations were identified in scmR, a gene encoding a quorum-sensing controlled LysR-type transcriptional regulator. B. pseudomallei strains with deletion mutations in hmqD and scmR were unable to produce 2-alkylquinolone derivatives or inhibit Bacteroidota isolates in competition assays. RAW264.7 murine macrophage cells were infected with B. pseudomallei 1026b and 1026b ΔhmqD and there was a 94-fold reduction in the number of intracellular 1026b ΔhmqD bacteria relative to 1026b. The 50% lethal dose (LD50) of 1026b and 1026b ΔhmqD in BALB/c mice was determined to be 3 x 105 colony forming units (CFU) and > 1 x 106 CFU, respectively. Taken together, the results indicate that the products of the B. pseudomallei hmqA-G locus are important for intracellular replication in murine macrophages, virulence in a mouse model of melioidosis, and competition with bacteria that utilize naphthoquinones for aerobic respiration.

Antibacterial Effects of Crude Venom from Aegaeobuthus gibbosus (Brulle, 1832)

Scorpion venom, found in the telsons of scorpions, is a neurotoxic secretion consisting of numerous proteins, peptides, and biologically active compounds, and it is commonly used in catching and digesting prey. The peptides within scorpion venoms hold significant pharmacological importance, particularly in the fields of cancer treatment, analgesics, and anesthesia. In recent years, bacteria developing resistance to antibiotics drew a significant level of interest. The present study investigates the antibacterial activity of the venom obtained from Aegaeobuthus gibbosus (Brulle, 1832). The antibacterial effects were observed by applying crude venom by using the dripping method on Escherichia coli, Proteus vulgaris, and Klebsiella pneumoniae bacteria in suitable environments. As a result, it was determined that the venom of Aegaeobuthus gibbosus is effective against Escherichia coli, Proteus vulgaris, and Klebsiella pneumoniae bacteria.

Long-Time Scale Simulations Reveal Key Dynamics That Drive the Onset of the N State in the Proteorhodopsin Photocycle.

Proteorhodopsin (PR) is a microbial proton pump that plays a significant role in phototrophy of bacteria in marine environments. Fundamental understanding of the structure-function relationship that drives proton pumping in PR has largely been elusive due to a lack of high-resolution structures of the photointermediates in the PR photocycle. Extending upon previous work, we used long-time scale molecular dynamics (MD) simulations to characterize the M state of the blue variant of PR, which represents the first proton transfer that takes place in the photocycle. Several notable structural changes occur in the M state that are hallmarks of subsequent steps in the PR photocycle, indicating that although this protein is often compared to the canonical microbial rhodopsins, such as bacteriorhodopsin, PR possesses characteristics that make it distinct among the rapidly increasing and widely variable catalog of microbial rhodopsins.

Anions exacerbate microbial corrosion of X80 pipeline steel induced by sulfate-reducing bacteria in the sea mud environment

Sulfate-reducing bacteria (SRB) present in sea mud pose a challenge to the safe operation of subsea pipelines. Chlorides and sulfates in sea mud promote the microbial corrosion of subsea pipelines by SRB. This study investigates the effects of sulfate and chloride on the microbial corrosion of X80 pipeline steel in the sea mud environment. The results indicate that sulfate serves as an electron acceptor, promoting the growth of SRB, while chloride regulates the osmotic pressure of SRB cells, affecting their bioactivity. SRB exhibit more aggressive corrosion behavior in sea mud with high concentrations of both chloride and sulfate.

Whole-genome sequencing of a Janthinobacterium sp. isolated from the Patagonian Desert.

Janthinobacterium is a genus of Gram-negative environmental bacteria that survive extreme conditions by forming biofilms and producing pigments. Janthinobacterium sp. LS2A, an extremophile isolated from soil in the Chilean Patagonia, contains seven known biosynthetic gene clusters, including the purple pigment violacein, which may aid in its survival in harsh environments.

Modelling a Western Lifestyle in Mice: A Novel Approach to Eradicating Aerobic Spore-Forming Bacteria from the Colonic Microbiome and Assessing Long-Term Clinical Outcomes.

The environmentally acquired aerobic spore-forming (EAS-Fs) bacteria that are ubiquitous in nature (e.g., soil) are transient colonisers of the mammalian gastro-intestinal tract. Without regular exposure, their numbers quickly diminish. These species of bacteria have been suggested to be essential to the normal functioning of metabolic and immunogenic health. The modern Western lifestyle restricts exposure to these EAS-Fs, possibly explaining part of the pathogenesis of many Western diseases. To date, the only animal studies that address specific microbiome modelling are based around germ-free animals. We have designed a new animal model that specifically restricts exposure to environmental sources of bacteria. A new protocol, termed Super Clean, which involves housing mice in autoclaved individually ventilated cages (IVCs), with autoclaved food/water and strict ascetic handling practice was first experimentally validated. The quantification of EAS-Fs was assessed by heat-treating faecal samples and measuring colony-forming units (CFUs). This was then compared to mice in standard conditions. Mice were housed in their respective groups from birth until 18 months. Stool samples were taken throughout the experiment to assess for abundance in transiently acquired environmental bacteria. Clinical, biochemical, histological, and gene expression markers were analysed for diabetes, hypercholesterolaemia, obesity, inflammatory bowel disease, and non-alcoholic fatty liver disease (the "diseases of the West"). Our results show that stringent adherence to the Super Clean protocol produces a significantly decreased abundance of aerobic spore-forming Bacillota after 21 days. This microbiomic shift was correlated with significantly increased levels of obesity and impaired glucose metabolism. There was no evidence of colitis, liver disease or hypercholesterolaemia. This new murine model successfully isolates EAS-Fs and has potential utility for future research, allowing for an investigation into the clinical impact of living in relative hygienic conditions.

InSeq analysis of defined Legionella pneumophila libraries identifies a transporter-encoding gene cluster important for intracellular replication in mammalian hosts.

Legionella pneumophila is an intracellular bacterial pathogen that replicates inside human alveolar macrophages to cause a severe pneumonia known as Legionnaires' disease. L. pneumophila requires the Dot/Icm Type IV secretion system to deliver hundreds of bacterial proteins to the host cytosol that manipulate cellular processes to establish a protected compartment for bacterial replication known as the Legionella-containing vacuole. To better understand mechanisms apart from the Dot/Icm system that support survival and replication in this vacuole, we used transposon insertion sequencing in combination with defined mutant sublibraries to identify L. pneumophila fitness determinants in primary mouse macrophages and the mouse lung. This approach validated that many previously identified genes important for intracellular replication were critical for infection of a mammalian host. Further, the screens uncovered additional genes contributing to L. pneumophila replication in mammalian infection models. This included a cluster of seven genes in which insertion mutations resulted in L. pneumophila fitness defects in mammalian hosts. Generation of isogenic deletion mutants and genetic complementation studies verified the importance of genes within this locus for infection of mammalian cells. Genes in this cluster are predicted to encode nucleotide-modifying enzymes, a protein of unknown function, and an atypical ATP-binding cassette (ABC) transporter with significant homology to multidrug efflux pumps that has been named Lit, for Legionella infectivity transporter. Overall, these data provide a comprehensive overview of the bacterial processes that support L. pneumophila replication in a mammalian host and offer insight into the unique challenges posed by the intravacuolar environment.IMPORTANCEIntracellular bacteria employ diverse mechanisms to survive and replicate inside the inhospitable environment of host cells. Legionella pneumophila is an opportunistic human pathogen and a model system for studying intracellular host-pathogen interactions. Transposon sequencing is an invaluable tool for identifying bacterial genes contributing to infection, but current animal models for L. pneumophila are suboptimal for conventional screens using saturated mutant libraries. This study employed a series of defined transposon mutant libraries to identify determinants of L. pneumophila fitness in mammalian hosts, which include a newly identified bacterial transporter called Lit. Understanding the requirements for survival and replication inside host cells informs us about the environment bacteria encounter during infection and the mechanisms they employ to make this environment habitable. Such knowledge will be key to addressing future challenges in treating infections caused by intracellular bacteria.

Comparative Analysis of Microbial Diversity and Metabolic Profiles during the Spontaneous Fermentation of Jerusalem Artichoke (Helianthus tuberosus L.) Juice.

Jerusalem artichoke juice is valued for its nutritional content and health benefits. Spontaneous fermentation enhances its flavor, quality, and functional components through microbial metabolic activities. This study used high-throughput sequencing to analyze microbial community changes, and LC-MS and GC-MS to detect secondary metabolites and flavor compounds during fermentation. During natural fermentation, beneficial bacteria like Lactobacillus and Pediococcus increased, promoting lactic acid production and inhibiting harmful bacteria, while environmental bacteria decreased. Similarly, fungi shifted from environmental types like Geosmithia and Alternaria to fermentation-associated Pichia and Penicillium. A total of 1666 secondary metabolites were identified, with 595 upregulated and 497 downregulated. Key metabolic pathways included phenylpropanoid biosynthesis, with significant increases in phenylalanine, tryptophan, and related metabolites. Lipid and nucleotide metabolism also showed significant changes. Flavor compounds, including 134 identified alcohols, esters, acids, and ketones, mostly increased in content after fermentation. Notable increases were seen in Phenylethyl Alcohol, Ethyl Benzenepropanoate, 3-Methylbutyl Butanoate, Ethyl 4-Methylpentanoate, 5-Ethyl-3-Hydroxy-4-Methyl-2(5H)-Furanone, Ethyl Decanoate, Hexanoic Acid, and 1-Octanol. γ-aminobutyric acid (GABA) and other functional components enhanced the health value of the juice. This study provides insights into microbial and metabolic changes during fermentation, aiding in optimizing processes and improving the quality of fermented Jerusalem artichoke juice for functional food development.