Elucidating the metabolic network and pH-dependent biosynthesis of bioactive exopolysaccharides XY1-EPS in Bacillus smithii.

Metagenomic profiles of marine microbial communities from Greenlandic coastal waters remain scarce, despite the central role played by this region in discussions of global climate change. This study characterizes the taxonomic and functional structure of two near-shore shallow marine fjord mouth microbial communities from sites in western Greenland that differ in sea-surface temperatures, mean annual ice-coverage levels and annual glacial meltwater flux rates. Results indicate limited taxonomic and functional overlap between these two locations, with significant differences in the normalized abundance of 3372 species (25% of observed taxa) and 620 functional genes (49% of functional genes observed). At Sisimiut, a typical open-water “Baffin Bay” site characterized by moderate sea-surface temperatures, minimal annual sea-ice cover and limited glacial input, the metagenome is dominated by diverse chemolithotrophic taxa, including sulphate-reducing, nitrogen-fixing and methanogenic lineages. At the Ilulissat Icefjord, where low sea-surface temperatures, high turbidity, low salinity and strong glacial influences prevail, the community is less diverse and is dominated by psychrophilic (cold-adapted) bacteria such as Colwellia hornerae PAMC 20917. Functional profiles further distinguish these sites: the Ilulissat metagenome is enriched in genes common to ice-associated and cold-adapted metabolisms (e.g., exopolysaccharide biosynthesis, dimethyl-sulphide and dimethylsulfoniopropionate cycling), whereas these genes are comparatively rare at Sisimiut. Together, these data sets provide a descriptive baseline for these two sites and a framework for future comparative studies in the region.

BackgroundMembers of the genus Labrys are widely distributed in soil and plant-associated environments, yet their ecological roles and functional contributions within plant-associated microbiomes remain poorly understood. Labrys methylaminiphilus strain La1 was isolated from nodules of Lupinus luteus growing in acidic soils of southern Chile, providing an opportunity to investigate strain-level traits relevant to plant–microbe interactions under environmental stress.MethodsStrain La1 was characterized using physiological and biochemical, chemotaxonomic, and genomic approaches, including whole-genome sequencing and comparative genomics. Functional traits related to plant interaction were assessed through in vitro assays for indole-3-acetic acid (IAA) production, antifungal activity against lupine pathogens, and in planta experiments evaluating plant growth under salinity and osmotic stress. The ecological distribution of closely related taxa was inferred from screening of publicly available environmental microbiomes using protologger pipeline.ResultsAlthough strain La1 showed high genomic similarity to L. methylaminiphilus JLW10T, it exhibited distinct phenotypic, metabolic, and ecological features. These included tolerance to acidic and moderately saline conditions, utilization of rhizosphere-associated carbon sources, and a fatty acid profile consistent with adaptation to terrestrial environments. Genomic analyses revealed genes related to stress tolerance, exopolysaccharide biosynthesis, carbohydrate-active enzymes, siderophore production, IAA synthesis, and non-ribosomal peptide synthetases. Consistent with these traits, La1 inhibited the growth of Colletotrichum lupini and Pleiochaeta setosa and significantly enhanced L. luteus biomass under osmotic and salinity stress. Metagenomic screening indicated that sequences closely related to La1 are predominantly associated with soil, rhizosphere, and plant-associated habitats.ConclusionThis study demonstrates that strain La1 represents a functionally versatile and ecologically specialized lineage within L. methylaminiphilus, contributing traits relevant to plant-associated microbiomes in acidic soils. This integrated functional and ecological evidence supports the designation of Labrys methylaminiphilus subsp. lupini subsp. nov. and highlights the relevance of strain-level analyses for understanding plant–microbe interactions.

Comparative genomic and phenotypic decoding of probiotic mechanisms in Weissella paramesenteroides strain MW-142

IntroductionThe genus Weissella comprises a diverse group of lactic acid bacteria (LAB) widely distributed across plant- and food-associated ecosystems and recognized for their functional and technological versatility. Weissella confusa UTNCys2-2, a plant-derived strain isolated from Amazonian spiral ginger (Costus sp.), that produces exopolysaccharides (EPS) with documented antioxidant activity and promising probiotic properties.MethodsWhole-genome sequencing of UTNCys2-2 was performed to establish its taxonomic assignment, phylogenomic analysis, while genome mining was conducted to evaluate safety, metabolic potential, and biosynthetic capabilities. Carbohydrate-active enzymes (CAZymes), Kyoto Encyclopedia of Genes and Genomes (KEGG), and MetaCyc pathways were analyzed for functional insights. Moreover, the metabolite composition of the cell-free supernatant (CFS) was examined using liquid chromatography–tandem mass spectrometry (LC–MS/MS) combined with Sequential Windowed Acquisition of all Theoretical Fragment Ion Mass Spectra (SWATH-MS).ResultsThe genome consists of a 2.32 Mb circular chromosome (44.59% GC) encoding 2,194 proteins, 76 tRNAs, and 10 rRNAs, with no plasmids. Phylogenomic analyses assigned the strain to the W. confusa clade, clustering closely with the reference strain DSM 20196. UTNCys2-2 harbors a complete Type II-A CRISPR-Cas system, intact prophages, and mobile elements, while lacking virulence determinants and transferable antimicrobial resistance genes. Functional annotation revealed 118 CAZymes supporting EPS biosynthesis, polysaccharide utilization, and carbohydrate metabolism. KEGG and MetaCyc pathways highlighted glycogen and riboflavin biosynthesis, stress tolerance, and metabolic versatility. Genome mining identified a Type III polyketide synthase (T3PKS) gene cluster with low similarity to known pathways, suggesting potential for novel secondary metabolites. Pangenome analysis showed extensive strain-specific genes linked to carbohydrate metabolism and EPS production. Metabolomic profiling of the CFS detected alkaloids, bioactive peptides, functional carbohydrates, and phenolics, supporting antimicrobial, probiotic, and host-interactive activities.ConclusionW. confusa UTNCys2-2 represents a biosafe and metabolically versatile strain with strong genomic capacity for EPS production, potential for novel secondary metabolite biosynthesis, and diverse bioactive properties, supporting its applicability in food fermentation, probiotic development, and microbial biotechnology.

Lactiplantibacillus plantarum, a ubiquitous probiotic in fermented foods and the human gut, relies on gastrointestinal tract colonization for its health-promoting functions. Central to this colonization is Sortase A (SrtA), a transpeptidase that anchors LPXTG motif-containing proteins to the cell wall peptidoglycan layer. This study investigates the srtA-mediated regulatory axis linking cell wall integrity, biofilm formation, and quorum sensing (QS) to adhesion properties in L. plantarum C8 (CGMCC No. 30504). Gene Ontology (GO)-KEGG enrichment analysis reveals that srtA deletion disrupts pathways critical for environmental adaptation, including two-component signal transduction and AI-2-dependent QS. Furthermore, the results of differential gene expression analysis indicate that srtA deletion is associated with the downregulation of genes involved in pyruvate metabolism, amino sugar/nucleotide sugar metabolism (essential for exopolysaccharide biosynthesis), and cell wall-associated signaling cascades, processes linked to adhesion and colonization. The molecular-level alterations were consistent with the observed phenotypic changes, including impaired cell wall integrity, reduced adhesion, and diminished biofilm-forming capacity. These results establish a mechanistic connection between srtA-directed cell wall anchoring, QS-regulated biofilm dynamics, and probiotic adhesion efficacy in L. plantarum.IMPORTANCEGastrointestinal tract colonization is the foundation of probiotic efficacy, enabling Lactiplantibacillus plantarum to modulate the gut microbiota, reinforce intestinal barriers, and confer health benefits. Sortase A (SrtA) is central to this process, covalently anchoring LPXTG-containing surface proteins that mediate adhesion, biofilm formation, and immune modulation. While srtA's role in pathogenic Gram-positive bacteria is well documented, its regulatory functions in non-pathogenic probiotic strains remain largely unexplored-especially regarding its integration with quorum sensing (QS) and environmental adaptation pathways. This study dissects the srtA-mediated molecular network in L. plantarum C8, revealing srtA as a master regulator integrating cell wall integrity, QS-regulated biofilm dynamics, and surface protein function via pathways including pyruvate and amino sugar/nucleotide sugar metabolism. These insights provide a mechanistic foundation for engineering probiotic strains with enhanced adhesion, colonization, and persistence and offer a scientific basis for developing precision-targeted functional foods and therapeutics.

This study provides an in-depth genomic and functional characterization of Lactiplantibacillus pentosus LP309, a strain isolated from table olive fermentations. The microorganism was sequenced using three next‑generation sequencing platforms—Illumina, PacBio, and Oxford Nanopore Technologies (ONT)—and multiple assembly and polishing strategies were evaluated. Assembly performance and annotation quality metrics were compared across approaches, and the most complete hybrid assembly for this study (Illumina + ONT) was selected for comprehensive genomic characterization. The complete chromosome was circularized at 3,523,074 bp, and together with eight plasmids, the total genome length reached 3,743,370 bp, comprising 3,448 coding sequences (CDSs) and reflecting the genomic complexity of LP309 strain. Taxonomic assignment based on Average Nucleotide Identity confirmed the species identity, while functional annotation predicted the presence of two bacteriocin and two exopolysaccharide biosynthesis clusters. Additionally, over 150 genes related to the probiotic and technological potential of the strain were also identified, including those involved in adhesion, acid stress resistance, vitamin biosynthesis, and carbohydrate metabolism, among others. Safety assessment confirmed the absence of genes associated with virulence, antibiotic or acquired antimicrobial resistance. Mobilome analysis revealed four prophages, 133 insertion sequences, and four genomic islands, while no integrons were detected. This in silico study has revealed the strong technological relevance and probiotic potential of LP309, establishing this plant-based bacterium as a safe and functionally versatile candidate for applications in the food and biotechnology industries.

Microbial exopolysaccharides (EPS) are increasingly recognized as effective, biodegradable, and low-toxicity biomaterials for the remediation of heavy metal-contaminated environments. Their high metal-binding capacity, chemical tunability, and microbial renewability make EPS attractive alternatives to conventional physicochemical adsorbents. Although numerous studies have reported the application of EPS in the removal of heavy metals and other toxic pollutants, existing literature remains fragmented, with limited integration of EPS production pathways, structure-function relationships, comparative adsorption performance and limited guidance on scalable production strategies.A key contribution is a consolidated comparative analysis of adsorption capacities of EPS, derived from different microbial taxa against major heavy metals, enabling informed selection of high-performing EPS systems for remediation applications. Furthermore, the review systematically categorizes the major metabolic pathways involved in EPS biosynthesis and identifies key microorganisms utilizing these pathways, highlighting regulatory factors influencing EPS yield and composition. Special emphasis is placed on bioreactor-based EPS production strategies, including batch, fed-batch, and continuous systems, and their role in improving productivity, consistency, and scalability.Emerging approaches such as EPS-based nanocomposites, hybrid materials, and bioengineered microbial systems are also discussed as promising solutions to overcome these limitations. This article provides a comprehensive and critical synthesis of microbial EPS in environmental remediation, focusing on their biosynthesis pathways, physicochemical characteristics, and adsorption mechanisms governing pollutant sequestration. By integrating microbial physiology with performance-oriented remediation outcomes, this review identifies critical bottlenecks and future research priorities required to advance microbial EPS from laboratory demonstrations toward cost-effective and scalable environmental remediation technologies.

Exopolysaccharides of Streptococcus mutans Enhance Oral Colonisation and Drug Tolerance in Helicobacter pylori

Exopolysaccharides (EPS) are natural macromolecular carbohydrates with good functional activity and physiological activities, but their industrial application was limited by high production costs and unclear structure-function relationships. This study developed a circular economy strategy to produce EPS via microbial fermentation using two food processing wastes (cane molasses and soy sauce residue). After optimizing fermentation medium, the waste-based system achieved an EPS yield of 33.06 ± 0.54g/L. Two heteropolysaccharides-EPS-2 and EPS-3 were successfully isolated and purified. Monosaccharide composition analysis revealed that EPS-2 primarily consisted of arabinose, glucose, and galactose in a ratio of 65.35:20.82:13.83. In contrast, EPS-3 exhibited a more complex profile containing rhamnose (33.54%), galactose (31.62%), fucose (17.93%), arabinose (13.47%), and glucose (3.44%). Notably, EPS-3 demonstrated higher antioxidant activity than EPS-2. This study successfully demonstrates an innovative waste-to-value conversion strategy that not only achieves high-value utilization of discarded resources but also establishes the fundamental theoretical framework for scalable production of renewable biopolymers.

Exopolysaccharides (EPS) are critical components of the biofilm matrix, and ppGpp has been demonstrated to positively influence biofilm formation. Here, we elucidate the underlying mechanism by which ppGpp regulates EPS production by facilitating HpaR1 to modulate the expression of the gum cluster in the phytopathogen Xanthomonas campestris pv. campestris (Xcc). ppGpp affected the yield of EPS without influencing its primary or advanced structure, as confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy. Expression of the gum cluster, which governs EPS biosynthesis in Xcc, was down-regulated in the ppGpp-deficient mutant (ΔrelAΔspoT) compared to the wild type (WT). Comparison of EPS production between knock-out mutants of the gum cluster and ppGpp-deficient mutant revealed that the gum cluster was a key determinant of EPS production, with ppGpp acting upstream of the gum cluster. Transcriptomic and qPCR analyses indicated that ppGpp modulated global transcription in Xcc, positively regulating expression of hpaR1, which encodes the transcription factor for the gum cluster. This regulatory role was further substantiated by electrophoretic mobility shift assays, which showed that ppGpp enhanced the DNA-binding activity of HpaR1. Furthermore, genetic complementation with hpaR1 restored EPS production, confirming its functional role in this regulatory pathway. In summary, these findings provide novel insights into the molecular mechanisms linking ppGpp signaling to EPS production in X. campestris pv. campestris.

This study characterized the exopolysaccharide (EPS) of Lactiplantibacillus plantarum L75 and investigated its biosynthesis and the strain's cold adaptation mechanisms. Strain L75 produced 161.2 ± 13.75 mg/L of a heteropolysaccharide (358.24 kDa) at 37 °C, composed of glucose (32.68%), mannose (30.53%), galactose (17.75%), glucuronic acid (12.63%), and rhamnose (6.41%). Crucially, this EPS promoted L. plantarum L75 growth at 15 °C. Genomic analysis revealed two typical wzx/wzy-dependent EPS gene clusters and a versatile carbohydrate metabolism capacity. Transcriptomic profiling confirmed L75's multifaceted cold adaptation, involving the upregulation of cold shock proteins and molecular chaperones, enhanced reactive oxygen species (ROS) scavenging, accumulation of compatible solutes, and maintenance of membrane fluidity. By integrating physiological and transcriptional data, our findings elucidate the molecular basis for L75's high EPS production, the role of EPS in low-temperature growth, and its robust cold tolerance, supporting its potential as a functional silage inoculant for cold regions.

The persistent threat of multidrug-resistant bacteria,particularlywithin biofilms, continues to undermine conventional antimicrobialtherapies. In this study, we explored the potential of zinc oxide(ZnO) and zinc sulfide (ZnS) nanoparticles (NPs) as alternative strategiesto target clinically relevant bacteria such as Staphylococcusaureus, Klebsiella oxytoca, and Pseudomonas aeruginosa. BothNPs exhibited effective antibacterial activity against planktonicforms, with ZnO more potent in vitro. However, ZnS-NPswere more efficacious in disrupting mature biofilms by compromisingtheir metabolic activity. Scanning electron and confocal microscopyrevealed that Zn-NP treatment compromised the structural integrityof the biofilms. ZnS-NPs also triggered a marked downregulation ofgenes associated with P. aeruginosa exopolysaccharide biosynthesis (e.g., pslA and algC), suggesting specific interference in biofilm formationpathways. Topical treatment of skin wound infection in Balb/c miceled to a significant reduction in bacterial burden. Notably, whileZn-NPs did not promote initial wound healing, they inhibited the degradationof collagen by bacteria and/or helped maintain collagen levels inthe skin of the mice. These findings demonstrate that Zn-NPs effectivelyreduce early bacterial burden in mouse skin wounds while preservingcutaneous tissue collagen integrity, establishing their dual therapeuticpotential as both antimicrobial and tissue-protective agents in woundmanagement.

Porphyridium species are known red microalgae for producing valuable bioactive compounds such as sulfated exopolysaccharides (EPS) with diverse industrial biomedical applications due to their functional and rheological properties. Recent studies have investigated how abiotic stresses, particularly nitrogen deprivation, affect Porphyridium’s metabolic regulation and EPS production through transcriptomic analysis. Still, the mechanisms governing EPS biosynthesis and the involvement of carbohydrate-activated enzymes (CAZymes) remain poorly understood. This study investigated the progressive effects of nitrate consumption on the unicellular red alga, P. purpureum, by integrating physiological, biochemical, and transcriptomic analyses through RNA-Seq, further validated by RT-qPCR. P. purpureum displayed a gradual, phase-dependent metabolic response to progressive nitrogen stress. EPS release coincided with the decline in nitrate uptake, linking nitrogen availability to carbon redirection towards polysaccharide secretion. Transcriptomic data revealed global metabolic downregulation with targeted upregulation of stress-responsive, carbohydrate catabolic, and nucleotide–sugar synthesis pathways, including the upregulation of CAZyme families GT4, GT8, and GT77. Our results give insights into the coordinated nitrogen and carbon metabolic regulation underlying polysaccharide biosynthesis, while opening future perspectives on enzyme compartmentalization and regulatory flux distribution under nitrogen stress in P. purpureum.

Lactic acid bacteria (LAB) play a vital role in the production of fermented foods, with certain strains being capable of producing exopolysaccharides (EPS) that may enhance the texture and functionality of fermented food products. Among these, bacterial β-glucan produced by LAB - a specific type of EPS - offers favorable rheological properties and potential health benefits, making it particularly valuable for food applications. In this study, a combined phenotypic and genotypic screening strategy was used to identify LAB strains potentially capable of producing β-glucan and suitable for use in food fermentations, with an emphasis on fruit-based products. From a collection of 246 LAB isolates, six EPS-producing strains harboring the gtf-2 gene, which encodes β-glucan synthase, were selected for further characterization. Notably, Lacticaseibacillus paracasei LTH 2407, isolated from Gouda cheese, is the first known member of its genus carrying a gtf-2 gene. Genomic and metabolic analyses revealed strain-specific profiles related to sugar transport, carbohydrate metabolism, and EPS biosynthesis, indicating their potential applicability in diverse food matrices, including fruit fermentations. A genome-based safety assessment showed no evidence of toxin production, antimicrobial resistance genes, or the genetic potential for producing highly toxic biogenic amines such as histamine or tyramine. These findings support the potential suitability of the selected strains for safe use as starter cultures in food fermentations. The study provides a solid basis for further analysis of the fermentation performance, EPS production capacity, and industrial relevance of these β-glucan-producing LAB strains.

Cyanobacterial exopolysaccharides (EPS) are natural biopolymers with substantial applications in the nutraceutical and food industries. This work included the isolation of a freshwater cyanobacterium, Leptolyngbya sp. MKU-05, and the optimization of its exopolysaccharide synthesis by response surface methodology. A central composite rotatable design yielded a maximum EPS production of 567.3mg L- 1 under optimized medium conditions. The ExoD paralogs have a direct impact on EPS synthesis, as gene expression analysis demonstrated a 4.5-fold increase in the EPS biosynthetic gene ExoD2 relative to unoptimized conditions. Partial structural characterization of purified EPS was deduced using Fourier-Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) analysis were used to partially characterize the structure of purified EPS and validate the presence of carboxyl, hydroxyl, and amide functional groups. Monosaccharide profiling indicated arabinose as a major component. SEM and XRD analyses revealed a fibrous, porous, and semi-crystalline nature of the EPS structure. Functionally, the EPS exhibited significant anti-inflammatory and antioxidant activities compared to the commercial drug mesalazine. Toxicological assessments using human embryonic kidney cells (HEK293 cells), human erythrocytes, and Artemia nauplii confirmed the non-toxic nature of the EPS. Notably, the EPS promoted cell proliferation and improved A. nauplii survival, further supporting its biocompatibility and safety. Collectively, the EPS from Leptolyngbya sp. MKU-05 EPS is a multifunctional and safe biopolymer with promising therapeutic and nutraceutical applications.

Bradyrhizobium, the largest rhizobial genus, is characterized by a variety of exopolysaccharide (EPS) components, such as penta- and tetrasaccharides, depending on the species. However, several genes involved in EPS synthesis remain unknown. In this study, we investigated whether 186 Bradyrhizobium strains possess homologous genes in the EPS cluster I, which is responsible for the synthesis of a pentasaccharide EPS by B. diazoefficiens USDA110. The absence of homologous genes in the B. elkanii and Photosynthetic Bradyrhizobium supergroups, in contrast to the B. japonicum supergroup, suggests that these lineages may utilize distinct and uncharacterized genes involved in tetrasaccharide EPS biosynthesis.

In this study, the effect of heat stress on the synthesis and the structural and physicochemical properties of exopolysaccharides (EPSs) from Rhodotorula glutinis YM25079 as well as its underlying mechanisms were explored. The results showed that the monosaccharide compositions of the purified YM25079 EPSs produced under normal culture conditions and heat stress (named EPS Y-1 and EPS Y-2, respectively) were consistent. Analyses of ion-exchanged chromatography, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy suggested that these two EPSs should be dextran, consisting mainly of α-(1→6)-linked glucopyranose units with α-(1→3) branches. Scanning Electron Microscope observed obvious differences in their surface morphologies, with EPS Y-1 showing a smooth, glossy lamellar structure and EPS Y-2 showing an irregular porous structure. According to Atomic Force Microscopy analysis, they formed aggregations with different cohesive structures. EPS Y-2 also had higher molecular weight and thermal stability than EPS Y-1, while EPS Y-1 had better α-amylase inhibitory activity. In addition, transcriptomic analysis unveiled changes in the metabolic pathways related to the uptake and utilization of carbon, nitrogen and phosphor sources, the biosynthesis of steroid and the oxidoreductase activity, as well as the regulatory genes implicated in the EPS biosynthesis under heat stress.

Most lactic acid bacteria synthesize exopolysaccharides during fermentation. Exopolysaccharides improve the stability and sensory profile of finished products by acting as thickeners or prebiotics. Exopolysaccharides are biologically active: they have antioxidant, immunomodulatory, and antitumor properties, as well as improve intestinal microbiota and reduce cholesterol. Polysaccharides of lactic acid bacteria meet the growing global demand for natural functional foods. Modern starter cultures can improve the sensory and rheological characteristics of the product. Exopolysaccharideproducing bacteria improve the quality of starter cultures. The nutrient medium composition (carbon, nitrogen, vitamins, minerals) and cultivation conditions (temperature, pH) affect the biosynthesis and yield of exopolysaccharides. They depend on the genus and species of lactic acid bacteria. Exopolysaccharides of lactic acid bacteria intensify dairy fermentation and reduce curd formation time, as well as stimulate the growth of associated probiotic microflora and the synthesis of beneficial metabolites. Studies of molecular composition and structure of exopolysaccharide-producing bacteria make it possible to explore the beneficial properties of polysaccharides, apply them in medicine, develop new functional starters, improve food quality, etc. This article reviews the most popular methods of exopolysaccharide studies, including their structure and monosaccharide composition.

Background/Objectives: The growing demand for functional foods and alternative therapeutic strategies has intensified the search for novel probiotic strains from underexplored ecosystems. This study aimed to isolate and phenotypically characterize lactic acid bacteria (LAB) from spontaneously fermented fruits found in the Legal Amazon (Ananas comosus, Humiria balsamifera, Manilkara zapota, and Platonia insignis) and to perform genome-based analysis of the most promising isolate to evaluate its probiotic potential. Methods: The isolates were identified by MALDI-TOF-MS and screened for tolerance to low pH, bile salts, lysozyme, growth at 39 °C, and antimicrobial activity against five enteric pathogens. The most promising isolate was evaluated by coaggregation and biofilm assays, in silico proteome and CAZyme analysis, bacteriocin cluster mining, and in vivo efficacy testing using Tenebrio molitor larvae. Results: Three isolates from H. balsamifera were identified as Lactiplantibacillus plantarum (M1, M2, M4) by MALDI-TOF-MS. These isolates exhibited high resilience to all tested physiological stressors. Antimicrobial activity was contact-dependent, with no inhibition by cell-free supernatants. M2 showed the strongest pathogen exclusion, moderate biofilm formation, and high coaggregation with S. enterica and E. faecalis. Genome analysis of M2 revealed a 3.40 Mb chromosome, absence of acquired resistance or virulence genes, two plantaricin gene clusters, and 93 CAZymes, including GT families linked to exopolysaccharides biosynthesis. SignalP predicted secretion signals in 10 CAZymes. M2 significantly improved larval survival against E. coli and S. enterica, especially under prophylactic treatment. Conclusions: L. plantarum M2 combines safety, stress tolerance, genomic features, and in vivo efficacy, positioning it as a promising probiotic candidate adapted to tropical niches. These findings highlight H. balsamifera as a reservoir of novel probiotic strains.