Fructobacillus Fructosus Research Articles

Exploring the Diversity and Potential Use of Flower-Derived Lactic Acid Bacteria in Plant-Based Fermentation: Insights into Exo-Cellular Polysaccharide Production.

Isolation of new plant-derived lactic acid bacteria (LAB) is highly prioritized in developing novel starter cultures for plant-based fermentation. This study explores the diversity of LAB in Danish flowers and their potential use for plant-based food fermentation. A total of 46 flower samples under 34 genera were collected for LAB isolation. By introducing an enrichment step, a total of 61 LAB strains were isolated and identified using MALDI-TOF and 16S rRNA sequencing. These strains represent 24 species across 9 genera, predominantly Leuconostoc mesenteroides, Fructobacillus fructosus, Apilactobacillus ozensis, and Apilactobacillus kunkeei. Phenotypic screening for exo-cellular polysaccharide production revealed that 40 strains exhibited sliminess or ropiness on sucrose-containing agar plates. HPLC analysis confirmed that all isolates produced exo-cellular polysaccharides containing glucose, fructose, or galactose as sugar monomers. Therefore, the strains were glucan, fructan, and galactan producers. The suitability of these strains for plant-based fermentation was characterized by using almond, oat, and soy milk. The results showed successful acidification in all three types of plant-based matrices but only observed texture development in soy by Leuconostoc, Weissella, Lactococcus, Apilactobacillus, and Fructobacillus. The findings highlight the potential of flower-derived LAB strains for texture development in soy-based dairy alternatives.

Apple Blossom Agricultural Residues as a Sustainable Source of Bioactive Peptides through Microbial Fermentation Bioprocessing.

This study explored the impact of starter-assisted fermentation on apple blossoms to enhance their potential as a source of antioxidant and antifungal molecules. Fructobacillus fructosus PL22 and Wickerhamomyces anomalus GY1 were chosen as starters owing to their origin and promising ability to modify plant secondary metabolites. An initial assessment through microbiological and physicochemical analyses showed superior outcomes for starter-assisted fermentation compared to the spontaneous process. Enzymatic hydrolysis of proteins, primarily controlled by starters, orchestrated the generation of new low-molecular-weight peptides. W. anomalus GY1 also induced modifications in the phenolic profile, generating a diverse array of bioactive metabolites. These metabolic changes, particularly the release of potentially bioactive peptides, were associated with significant antioxidant activity and marked antifungal efficacy against three common mold species. Our results shed light on the potential of microbial starters to valorize agricultural wastes and convert them into a valuable resource for industry.

Effects of physical sterilization on microbial safety, nutritional composition, and antioxidant activity of queen bee larva powder, a by-product of royal jelly production

Queen bee larvae (QBL), a by-product of royal jelly production, have nutritional value and confer health benefits. The commercialization of QBL is hindered because of the lack of evidence for its nutrition and safety parameters. Thus, this study was conducted to investigate the microbial dynamics, nutritional composition, and antioxidant activity of QBL, aiming to assess its potential as a food product. Lyophilized QBL powder samples were sterilized through gamma irradiation and high-pressure processing at varying doses and pressures. Gamma irradiation at 10 and 15 kGy effectively reduced the total aerobic count to 0, whereas high-pressure processing led to no significant reduction. Regarding the microbial profile of QBL, 16S rDNA gene sequencing unveiled five bacteria—Acinetobacter pittii, Bacillus thuringiensis, Enterococcus mundtii, Enterococcus faecalis, and Fructobacillus fructosus—but no major foodborne pathogens. Lactobacillus, Bombella, and Fructobacillus emerged as the predominant genera in QBL, with low abundances of Staphylococcus and Escherichia. Proximate composition analysis indicated no significant postirradiation changes in macronutrient contents; notably, protein was the predominant component (approximately 48.0%). Sugar and amino acid analyses revealed essential nutrients meeting human dietary requirements. Upon fatty acid analysis, palmitic and oleic acids emerged as predominant fatty acids. Gamma irradiation at 10 kGy exerted no significant effect on the nutritional composition or antioxidant activity of QBL. Our study provides valuable insights into the microbial safety and nutritional value of QBL, indicating its potential as a dietary protein source with favorable microbiota.

Eupransor demetentiae gen. nov., sp. nov., a novel fructophilic lactic acid bacterium from bumble bees.

Strain LMG 33000T was isolated from a Bombus lapidarius gut sample. It shared the highest percentage 16S rRNA sequence identity, average amino acid identity, and amino acid identity of conserved genes with Convivina intestini LMG 28291T (95.86 %, 69.9 and 76.2 %, respectively), and the highest percentage OrthoANIu value with Fructobacillus fructosus DSM 20349T (71.4 %). Phylogenomic analyses by means of 107 or 120 conserved genes consistently revealed Convivina as nearest neighbour genus. The draft genome of strain LMG 33000T was 1.44 Mbp in size and had a DNA G+C content of 46.1 mol%. Genomic and physiological analyses revealed that strain LMG 33000T was a typical obligately fructophilic lactic acid bacterium that lacked the adhE and aldh genes and that did not produce ethanol during glucose or fructose metabolism. In contrast, Convivina species have the adhE and aldh genes in their genomes and produced ethanol from glucose and fructose metabolism, which is typical for heterofermentative lactic acid bacteria. Moreover, strain LMG 33000T exhibited catalase activity, an unusual characteristic among lactic acid bacteria, that is not shared with Convivina species. Given its position in the phylogenomic trees, and the difference in genomic percentage G+C content and in physiological and metabolic characteristics between strain LMG 33000T and Convivina species, we considered it most appropriate to classify strain LMG 33000T into a novel genus and species within the Lactobacillaceae family for which we propose the name Eupransor demetentiae gen. nov., sp. nov., with LMG 33000T (=CECT 30958T) as the type strain.

Characterization of lactic acid bacteria isolated from the gastrointestinal tract of scaptotrigona mexicana and scaptotrigona pectoralis stingless bees

Stingless bees play an essential role as pollinators and have economic and cultural importance for their honey production. In the last decades, there has been a decrease in their populations by multiple factors. Stingless bees engage in symbiotic relationships with many microorganisms, some of which benefit the host nutritionally and protect them from natural enemies. Lactic acid bacteria benefit the host, but their probiotic ability depends on their antimicrobial capacity. This study included isolating and characterizing eight strains of lactic acid bacteria from the gastrointestinal tracts of stingless bees (Scaptotrigona mexicana and Scaptotrigona pectoralis). The bacterial phenotypic profile and antimicrobial activity, in vitro, against the pathogen Paenibacillus larvae and other common pathogens of the isolated bacteria, were also investigated. It was found that Weisella sp, Fructobacillus tropaeoli, Fructobacillus fructosus, and Fructobacillus pseudoficulneus showed probiotic potential.

A comparative genomic analysis of Fructobacillus evanidus sp. nov. from bumble bees

The increase in studies on bee microbiomes is prompted by concerns over global pollinator declines. Bumble bees host core and non-core microbiota which may contribute to increased lifetime fitness. The presence of Fructobacillus in the gut microbiomes of bumble bee workers, or the replacement of core symbionts with Fructobacillus bacteria, has been considered a marker of dysbiosis. A phylogenomic analysis and functional genomic characterization of the genomes of 21 Fructobacillus isolates from bumble bees demonstrated that they represented four species, i.e. Fructobacillus cardui, Fructobacillus fructosus, Fructobacillus tropaeoli, and the novel species Fructobacillus evanidus sp. nov. Our results confirmed and substantiated the presence of two phylogenetically and functionally distinct Fructobacillus species clades that differ in genome size, percentage G + C content, the number of coding DNA sequences and metabolic characteristics. Clade 1 and clade 2 species differed in amino acid and, to a lesser extent, in carbohydrate metabolism, with F. evanidus and F. tropaeoli genomes featuring a higher number of complete metabolic pathways. While Fructobacillus genomes encoded genes that allow adhesion, biofilm formation, antibacterial activity and detoxification, other bacteria isolated from the bumble bee gut appeared better equipped to co-exist with the bumble bee host. The isolation and identification of multiple Fructobacillus species from several bumble bee gut samples in the present study also argued against a specific partnership between Fructobacillus species and their bumble bee hosts.

Fructobacillus fructosus OS-1010 strain stimulates intestinal cells to secrete exosomes that activate muscle cells

Fructobacillus is a lactic-acid bacterium recently identified in fructose-rich environments. Fructobacillus is also known to exhibit unusual growth characteristics due to an incomplete gene encoding alcohol/acetaldehyde hydrogenase, which results in an imbalance in the nicotinamide adenine mononucleotide (NAD+)/NADN levels. Recently, the addition of d-fructose to the culture medium of Fructobacillus strains increased the intracellular nicotinamide mononucleotide (NMN) content. In the present study, we evaluated the functionality of Fructobacillus that produces high levels of NMN, using one substrain (Fructobacillus fructosus OS-1010). Therefore, in this study, we examined its functionality in the interaction between intestinal cells and muscle cells. The results showed that supernatant derived from intestinal epithelial cells (Caco-2 cells) treated with F. fructosus OS-1010 activated muscle cells (C2C12 cells). Further analysis revealed that Caco-2 cells treated with F. fructosus OS-1010 secreted exosomes known as extracellular vesicles, which activated the muscle cells. Furthermore, pathway analysis of the target genes of miRNA in exosomes revealed that pathways involved in muscle cell activation, including insulin signaling and cardiac muscle regulation, neurotrophic factors, longevity, and anti-aging, can be activated by exosomes. In other words, F. fructosus OS-1010 could activate various cells such as the skin and muscle cells, by secreting functional exosomes from the intestinal tract.

The Response of the Honey Bee Gut Microbiota to Nosema ceranae Is Modulated by the Probiotic Pediococcus acidilactici and the Neonicotinoid Thiamethoxam.

The honey bee Apis mellifera is exposed to a variety of biotic and abiotic stressors, such as the highly prevalent microsporidian parasite Nosema (Vairimorpha) ceranae and neonicotinoid insecticides. Both can affect honey bee physiology and microbial gut communities, eventually reducing its lifespan. They can also have a combined effect on the insect's survival. The use of bacterial probiotics has been proposed to improve honey bee health, but their beneficial effect remains an open question. In the present study, western honey bees were experimentally infected with N. ceranae spores, chronically exposed to the neonicotinoid thiamethoxam, and/or supplied daily with the homofermentative bacterium Pediococcus acidilactici MA18/5M thought to improve the honey bees' tolerance to the parasite. Deep shotgun metagenomic sequencing allowed the response of the gut microbiota to be investigated with a taxonomic resolution at the species level. All treatments induced significant changes in honey bee gut bacterial communities. Nosema ceranae infection increased the abundance of Proteus mirabilis, Frischella perrara, and Gilliamella apicola and reduced the abundance of Bifidobacterium asteroides, Fructobacillus fructosus, and Lactobacillus spp. Supplementation with P. acidilactici overturned some of these alterations, bringing back the abundance of some altered species close to the relative abundance found in the controls. Surprisingly, the exposure to thiamethoxam also restored the relative abundance of some species modulated by N. ceranae. This study shows that stressors and probiotics may have an antagonistic impact on honey bee gut bacterial communities and that P. acidilactici may have a protective effect against the dysbiosis induced by an infection with N. ceranae.

Characterization of Lactic Acid Bacteria Strains Isolated from Algerian Honeybee and Honey and Exploration of Their Potential Probiotic and Functional Features for Human Use.

Using culture enrichment methods, 100 strains of bacilli of lactic acid bacteria (LAB) were isolated from honeybee Apis mellifera intermissa and fresh honey, collected from apiaries located in the north-east of Algeria. Amongst all of the isolated LAB, 19 selected strains were closely affiliated to four species-Fructobacillus fructosus (10), Apilactobacillus kunkeei (5), Lactobacillus kimbladii and/or Lactobacillus kullabergensis (4)-using phylogenetic and phenotypic approaches. The in vitro probiotic characteristics (simulated gastrointestinal fluids tolerance, autoaggregation and hydrophobicity abilities, antimicrobial activity and cholesterol reduction) and safety properties (hemolytic activity, antibiotic resistance and absence of biogenic amines) were evaluated. The results indicated that some strains showed promising potential probiotic properties. In addition, neither hemolytic activity nor biogenic amines were produced. The carbohydrate fermentation test (API 50 CHL) revealed that the strains could efficiently use a broad range of carbohydrates; additionally, four strains belonging to Apilactobacillus kunkeei and Fructobacillus fructosus were found to be exopolysaccharides (EPS) producers. This study demonstrates the honeybee Apis mellifera intermissa and one of her products as a reservoir for novel LAB with potential probiotic features, suggesting suitability for promoting host health.

Convivina is a specialised core gut symbiont of the invasive hornet Vespa velutina.

We provide a culturomics analysis of the cultivable bacterial communities of the crop, midgut and hindgut compartments, as well as the ovaries, of the invasive insect Vespa velutina, along with a cultivation-independent analysis of samples of the same nest through 16S rRNA amplicon sequencing. The Vespa velutina bacterial symbiont community was dominated by the genera Convivina, Fructobacillus, Lactiplantibacillus, Lactococcus, Sphingomonas and Spiroplasma. Lactococcus lactis and Lactiplantibacillus plantarum represented generalist core lactic acid bacteria (LAB) symbionts, while Convivina species and Fructobacillus fructosus represented highly specialised core LAB symbionts with strongly reduced genome sizes. Sphingomonas and Spiroplasma were the only non-LAB core symbionts but were not isolated. Convivina bacteria were particularly enriched in the hornet crop and included Convivina intestini, a species adapted towards amino acid metabolism, and Convivina praedatoris sp. nov. which was adapted towards carbohydrate metabolism.

Assessment of technological and functional features of Lactiplantibacillus and Fructobacillus strains isolated from Opuntia ficus-indica fruits

Opuntia ficus-indica fruits are outstanding for their sensory attributes and multiple health benefits. However, this fruit is highly perishable, and substantial efforts have been carried out to extend its shelf-life. Lactic fermentation of fruits by-products using autochthonous bacteria arises as relevant technology for preserving vegetables and their by-products. In this study, autochthonous Lactiplantibacillus plantarum and Fructobacillus fructosus strains previously selected from Opuntia ficus-indica fruits of Northwestern Argentina were characterized according to their technological and functional properties to select the most suitable for the production of fermented cactus pear products. L. plantarum strains showed better acidifying activity, decreasing the pH of the juice by about 2.9 units in 24 h. All the strains studied produced lactic and propionic acids, and L.plantarum S-811 and S-TF2 strains and F. fructosus S-TF7 strain were the better lactic acid producers, with values around 9.5 g/l. These strains also displayed antimicrobial activities against undesirable pathogen bacteria, showed a safety profile typical of lactic acid bacteria, and the juice fermented with these strains preserves the phenolic compounds content and antioxidant activity of unfermented juice. The obtained results showed the potential of L.plantarum S-811 and S-TF2, and F. fructosus S-22 for their use as starters for the fermentation of cactus pear by-products, standing out L.plantarum S-811 for its potentiality to elaborate a fermented cactus pear beverage. The cactus pear juice fermented by L.plantarum S-811 showed physicochemical and microbiological stability that favors juice shelf-life. Besides, fermentation conferred distinctive sensory features to the cactus pear juice without influencing consumers' overall acceptability.

Fructose-induced topographical changes in fructophilic, pseudofructophilic and non-fructophilic lactic acid bacterial strains with genomic comparison.

Fructophilic Lactic Acid Bacteria (FLAB), Fructobacillus fructosus DPC7238 and pseudofructophilic Leuconostoc mesenteroides DPC7261 and non-FLAB Limosilactobacillus reuteri DSM20016 strains were studied for their growth and morphological evolution as a function of increased fructose concentrations (0, 25, and 50% w/v) in the media. A comparison of the genomics of these strains was carried out to relate observed changes and understand fructose-rich adaptations. The viability of FLAB strains were reduced by approx. 50% at a 50% fructose concentration, while the Limosilactobacillus reuteri strain was reduced to approx. 98%. Electron microscopy demonstrated that FLAB strain, Fructobacillus. fructosus and pseudofructophilic Leuc. mesenteroides, were intact but expanded in the presence of high fructose in the medium. Limosilactobacillus reuteri, on the other hand, ruptured as a result of excessive elongation, resulting in the formation of cell debris when the medium contained more than 25% (w/v) fructose. This was entirely and quantitatively corroborated by three-dimensional data obtained by scanning several single cells using an atomic force microscope. The damage caused the bacterial envelope to elongate lengthwise, thus increasing width size and lower height. The cell surface became comparatively smoother at 25% fructose while rougher at 50% fructose, irrespective of the strains. Although Fructobacillus fructosus was highly fructose tolerant and maintained topological integrity, it had a comparatively smaller genome than pseudofructophilic Leuc. mesenteroides. Further, COG analysis identified lower but effective numbers of genes in fructose metabolism and transport of Fructobacillus fructosus, essentially needed for adaptability in fructose-rich niches.

Antimicrobial Properties, Functional Characterisation and Application of Fructobacillus fructosus and Lactiplantibacillus plantarum Isolated from Artisanal Honey.

Honey is a valuable reservoir of lactic acid bacteria (LAB) and, particularly, of fructophilic LAB (FLAB), a relatively novel subgroup of LAB whose functional potential for human and food application has yet to be explored. In this study, FLAB and LAB strains have been isolated from honeys of different floral origins and selected for their broad antimicrobial activity against typical foodborne pathogenic bacteria and spoilage filamentous fungi. The best candidates, two strains belonging to the species Lactiplantibacillus plantarum and Fructobacillus fructosus, were submitted to partial characterisation of their cell free supernatants (CFS) in order to identify the secreted metabolites with antimicrobial activity. Besides, these strains were examined to assess some major functional features, including in vitro tolerance to the oro-gastrointestinal conditions, potential cytotoxicity against HT-29 cells, adhesion to human enterocyte-like cells and capability to stimulate macrophages. Moreover, when the tested strains were applied on table grapes artificially contaminated with pathogenic bacteria or filamentous fungi, they showed a good ability to antagonise the growth of undesired microbes, as well as to survive on the fruit surface at a concentration that is recommended to develop a probiotic effect. In conclusion, both LAB and FLAB honey-isolated strains characterised in this work exhibit functional properties that validate their potential use as biocontrol agents and for the design of novel functional foods. We reported antimicrobial activity, cytotoxic evaluation, probiotic properties and direct food application of a F. fructosus strain, improving the knowledge of this species, in particular, and on FLAB, more generally.

Viable fructophilic lactic acid bacteria present in honeybee-based food products.

Fructophilic lactic acid bacteria (FLAB) are a group of lactic acid bacteria (LAB) with unique growth characteristics and are regarded as promising candidates for foods or food ingredients. The present study characterized levels of viable FLAB cells in honeybee-based food products, especially focusing on fresh honey. FLAB were recovered from 88% of fresh honey samples (harvested within a week) tested, and 29% of the fresh honey samples contained FLAB with levels of over 105 CFU/g. FLAB species found in the tested fresh honeys were mostly Apilactobacillus kunkeei and Fructobacillus fructosus. FLAB were not recovered from aged honey samples (aged over 2 weeks after harvest). Fresh comb honey and bee pollen samples occasionally contained low levels of FLAB. When FLAB were inoculated into honeys (linden honey and clover honey), their viability markedly reduced during a week. One of the reasons for this decrease was the presence of H2O2 in the honeys, and supplementation of catalase significantly improved their survivability in linden honey. The long history of human consumption of fresh honey suggests that viable FLAB cells do not present health concerns.

Metagenomic Investigation Uncovers Presence of Probiotic-Type Microbiome in Kalparasa® (Fresh Unfermented Coconut Inflorescence Sap).

The phloem sap tapped from unopened inflorescence (spadix) of coconut palm using a novel collecting device, “coco-sap chiller,” has been branded Kalparasa® (henceforth as Kalparasa in the text) to distinguish its properties not found in sap harvested by traditional methods. To know its hitherto unidentified microbiome profile, we employed high-throughput sequencing to uncover the bacteriome and mycobiome in fresh and 12-h fermented samples. Fresh Kalparasa had a pH of 7.2, which dropped to 4.5 after 12 h, signifying fermentation of the sap. Diversity analysis indicated fresh Kalparasa having higher bacterial species than the fermented one. Contrary to this, fresh sap had lower fungal/yeast diversity than the fermented sample. Fresh Kalparasa had relatively higher abundance of probiotic-type Leuconostoc genus followed by equal proportions of Gluconobacter, Acetobacter, and Fructobacillus. The 12-h fermented Kalparasa showed a significant increase in Gluconobacter with a sharp decrease in Leuconostoc. Mycobiome data revealed fresh Kalparasa to be preponderant in Saccharomyces and Hanseniaspora genera of yeasts while the fermented sap had higher representation of Hanseniaspora and Cortinarius and lesser Saccharomyces. This suggested that the fermentation of Kalparasa was probably driven by symbiotic culture of bacteria and yeasts (SCOBY), particularly acetic acid bacteria and non-Saccharomyces yeasts. The bacteriome-function predictions highlighted the enrichment of glycerophospholipid, ABC transporters, purine, and pyrimidine metabolisms. Based on our findings, Kalparasa containing large population of Leuconostoc mesenteroides, Fructobacillus fructosus, Saccharomyces cerevisiae, and Hanseniaspora guilliermondii can be promoted as a healthy “unfermented” plant edible food containing live probiotic-type microbiome during its consumption.

Detection Bioactive Metabolites of Fructobacillus fructosus Strain HI-1 Isolated from Honey Bee's Digestive Tract Against Paenibacillus larvae.

American foulbrood is a devastating disease of honey bee, causing economic loss in the beekeeping industry. The disease mainly causes reduction in honeybee populations which negatively affect the honey bee's major role as natural pollinators of significant crops and wildflowers. Thus, it is crucial to develop safe efficient strategies to control the disease and to improve bee colony health. Using lactic acid bacteria (LAB) as an alternative to chemical treatments is a promising novel technique for tackling honeybee diseases and improving their immunity. The endogenous LAB isolates were recovered from honeybee gut samples collected from different apiaries in two Egyptian governorates and screened for antagonistic activities against Paenibacillus larvae (pathogen of AFB disease). The results showed that 53.3% of tested LAB isolates (n = 120) exhibited antagonistic activities against P. larvae. The minimum inhibitory concentration and minimum bactericidal concentration of the most potent LAB isolate (with an inhibition zone of 44 mm) were 100 and 125 µL/mL, respectively. 16S rRNA sequencing identified the most potent isolate as Fructobacillus fructosus HI-1. The bioactive metabolites of F. fructosus were extracted with ethyl acetate and fractionated on thin-layer chromatography (TLC); also, bioactive fractions were detected. Heptyl 2-methylbutyrate, di-isobutyl phthalate, D-turanose, heptakis (trimethylsilyl), di-isooctyl phthalate, and hyodeoxycholic acid compounds were identified in the bioactive fractions. The result explores the promising administration of probiotic metabolites to control honeybee AFB disease, as a natural tool to substitute antibiotics and chemicals in disease-controlling strategies.

Surface-enhanced Raman spectroscopy for identification of food processing bacteria

Food processing bacteria play important role in providing flavors, ingredients and other beneficial characteristics to the food but at the same time some bacteria are responsible for food spoilage. Therefore, quick and reliable identification of these food processing bacteria is very necessary for the differentiation between different species which may help in the development of more useful food processing methodologies. In this study, analysis of different bacterial species (Lactobacillus fermentum, Fructobacillus fructosus, Pediococcus pentosaceus and Halalkalicoccus jeotgali) was performed with our in-house developed Ag NPs-based surface-enhanced Raman spectroscopy (SERS) method. The SERS spectral data was analyzed by multivariate data analysis techniques including principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA). Bacterial species were differentiated on the basis of SERS spectral features and potential of SERS was compared with the Raman spectroscopy (RS). SERS along with PCA and PLS-DA was found to be an efficient technique for identification and differentiation of food processing bacterial species. Differentiation with accuracy of 99.5% and sensitivity of 99.7% was depicted by PLS-DA model using leave one out cross validation.

Detection of fructophilic lactic acid bacteria (FLAB) in bee bread and bee pollen samples and determination of their functional roles

In this study, bee bread and bee pollen samples were characterized in terms of presence of fructophilic lactic acid bacteria (FLAB). Following discrimination and identification of FLAB strains, their functional roles were determined. Genotypic characterization of FLAB strains revealed the presence of 27 distinct strains belonging to Lactobacillus kunkeei (21), Fructobacillus fructosus (3), Lactobacillus plantarum (2), and Leuconostoc mesenteroides (1) strains. In terms of functional roles, all FLAB strains demonstrated high levels of autoaggregation and hydrophobicity properties whereas L. kunkeei and F. fructosus strains did not tolerate bile salts and low pH conditions. A low level of antibiotic resistance was observed among FLAB strains and importantly FLAB strains demonstrated high levels of antibacterial and antifungal activities where strain specific properties played roles. The highest exopolysaccharide (EPS) production yields were obtained for L. kunkeei AP15, AP37 and L. mesenteroides AP-40 which produced 2.79, 2.01, and 5.37 g/L EPS, respectively. Practical applications Bee bread and bee pollen are among beneficial bee products produced and consumed in all over the world. Production of bee bread relies on the fermentation process of bee pollen where a special LAB group FLAB plays roles. Despite the increment of the importance of these products for human consumption, there is a lack of knowledge for the microbial composition of these products. In this study, FLAB strains were isolated and identified from bee bread and bee pollen samples, and their technofunctional role was determined. The FLAB strains would be evaluated as starter cultures for production of bee products under industrial conditions.

Cultured-dependent and cultured-independent study of bacteria associated with Thai commercial stingless bee Lepidotrigona terminata

This study aimed to investigate the lactic acid bacteria in stingless bees (Lepidotrigona terminata). Stingless bees were randomly collected from five different nests in Chiang Mai University, identified via the COI gene, and compared to those in the NCBI database. The result showed that all samples were L. terminata. Bees were extracted and subjected to 10-fold dilution to screen on MRS agar to estimate the number of lactic acid bacteria (LAB) cells in the samples. The colony forming unit (CFU) was between 1.28 x 10 6 ± 0.02 and 1.37 x 10 6 ± 0.08 CFU/g. Fifty isolates were chosen to perform an agar well assay to quantify the capacity of inhibiting against Paenibacillus larvae (strain LMG9820), a honey bee pathogen that causes American foulbrood. The results showed that bacteria from two nests (selected from those of the five nests) could inhibit the growth of P. larvae with the mean of a clear zone of 12.15 ± 0.2 mm. On the other hand, bacteria from the other three nests could not inhibit the pathogen. Identification of the effective bacteria species using 16S rRNA and the construction of the phylogenetic tree revealed that they were Fructobacillus fructosus of the Bacillus group. The cultured-independent result showed that Betaproteobacteria was the most abundant group (41.6%) of bacteria in stingless bees while Actinobacteria was the lowest in abundance (0.6%). Further experiments will need to be performed to examine the functions of these microorganisms in stingless bees.

Inter- and Intra-Species Diversity of Lactic Acid Bacteria in Apis mellifera ligustica Colonies.

Lactic acid bacteria could positively affect the health of honey bees, including nutritional supplementation, immune system development and pathogen colonization resistance. Based on these considerations the present study evaluated predominant Lactic Acid Bacteria (LAB) species from beebread as well as from the social stomach and midgut of Apis mellifera ligustica honey bee foragers. In detail, for each compartment, the diversity in species and biotypes was ascertained through multiple culture-dependent approaches, consisting of Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE), 16S rRNA gene sequencing and Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR). The study of a lactic acid bacteria community, performed with PCR-DGGE and sequence analysis targeting the V1–V3 region of the 16S rRNA gene (rDNA), highlighted the presence of a few species, including Apilactobacillus kunkeei, Lactiplantibacillus plantarum, Fructobacillus fructosus, Levilactobacillus brevis and Lactobacillus delbrueckii subsp. lactis. Depending on the different compartments, diverse levels of biodiversity in species were found. Particularly, a very low inter-species biodiversity was detected in the midgut that was prevalently dominated by the presence of Apilactobacillus kunkeei. On the other hand, the beebread was characterized by a reasonable biodiversity showing the presence of five species and the predominance of Apilactobacillus kunkeei, Lactiplantibacillus plantarum and Fructobacillus fructosus. The RAPD-PCR analysis performed on the three predominant species allowed the differentiation into several biotypes for each species. Moreover, a relationship between biotypes and compartments has been detected and each biotype was able to express a specific biochemical profile. The biotypes that populated the social stomach and midgut were able to metabolize sugars considered toxic for bees while those isolated from beebread could contribute to release useful compounds with functional properties. Based on this knowledge, new biotechnological approaches could be developed to improve the health of honey bees and the quality of bee products.