Synergistic Antioxidant and Anti-Inflammatory Activities of Kale Juice Fermented with Limosilactobacills reuteri EFEL6901 or Limosilactobacills fermentum EFEL6800.

This study investigates the synergistic impact of fermenting kale juice with Limosilactobacillus strains on its antioxidant and anti-inflammatory properties. Kale's rich nutrient profile, especially its flavonoids, offers potential health benefits. Probiotic lactic acid bacteria are employed in kale fermentation to enhance nutrient bioavailability and generate bioactive compounds. Kale juices fermented with L. reuteri EFEL6901 or L. fermentum EFEL6800 exhibited superior microbial growth. Free sugars and amino acids were converted to alcohols and organic acids, affecting the organoleptic and health-related properties of the product. In addition, fermentation increased quercetin and kaempferol content, indicating improved availability. Furthermore, the fermented juice exhibited notable antioxidant activity and suppressed nitric oxide (NO) production, revealing anti-inflammatory potential. Gene expression analysis confirmed reduced pro-inflammatory markers such as iNOS, COX-2, IL-6, and IL-1ß and elevated anti-inflammatory cytokines, including IL-10. This research highlights the promising potential of fermented kale juice, enriched with Limosilactobacillus strains, as a functional food with combined antioxidant and anti-inflammatory benefits.

Phenotypic and genomic analyses of bacteriocin-producing probiotic Enterococcus faecium EFEL8600 isolated from Korean soy-meju.

Enterococcus faecium is a prevalent species found in fermented soybean products, known for its contributions to flavor development and inhibition of pathogenic microorganisms during fermentation. This study aims to provide comprehensive phenotypic and genomic evidence supporting the probiotic characteristics of E. faecium EFEL8600, a bacteriocin-producing strain isolated from Korean soy-meju. Phenotypic analysis revealed that EFEL8600 produced a peptide with inhibitory activity against Listeria monocytogenes, estimated to be 4.6 kDa, corresponding to the size of enterocins P or Q. Furthermore, EFEL8600 exhibited probiotic traits, such as resilience in gastrointestinal conditions, antioxidant and anti-inflammatory activities, and protection of the intestinal barrier. Safety assessments demonstrated no hemolytic and bile salt deconjugation activities. Genomic analysis revealed the presence of several genes associated with probiotic characteristics and bacteriocin production, while few deleterious genes with a low likelihood of expression or transferring were detected. Overall, this study highlights E. faecium EFEL8600 as a potent anti-listeria probiotic strain suitable for use as a starter culture in soymilk fermentation, providing potential health benefits to consumers.

Strain-specific metabolomic diversity of Lactiplantibacillus plantarum under aerobic and anaerobic conditions.

The chemotaxonomic diversity of 20 Lactiplantibacillus plantarum strains was investigated using non-targeted metabolite profiling under different culture conditions. Multivariate and metabolic pathway analyses based on GC-MS and LC-MS/MS datasets showed that amino acid metabolism, especially 2-hydroxy acids, was enriched under aerobic conditions (AE), whereas fatty acid & sugar metabolism was increased under anaerobic conditions (AN). Based on the metabolite profiles, L. plantarum strains were clustered into three main groups (A, B, and C). Overall, 79 and 83 significantly discriminant metabolites were characterized as chemical markers of AE and AN growth conditions, respectively. Notably, alcohols were more abundant in group A whereas amino acids, peptides, purines, and pyrimidines were significantly higher in group C. 2-hydroxy acids and oxylipins biosynthesized through amino acid and fatty acid metabolism, respectively, were more abundant in groups A and B. Furthermore, we observed a strong correlation between the chemical diversity of L. plantarum groups and their antioxidant activity from metabolite extracts. We propose a non-targeted metabolomic workflow to comprehensively characterize the chemodiversity of L. plantarum strain under different culture conditions, which may help reveal specific biomarkers of individual strains depending on the culture conditions.

A qPCR Method to Assay Endonuclease Activity of Cas9-sgRNA Ribonucleoprotein Complexes.

The CRISPR-Cas system has emerged as the most efficient genome editing technique for a wide range of cells. Delivery of the Cas9-sgRNA ribonucleoprotein complex (Cas9 RNP) has gained popularity. The objective of this study was to develop a quantitative polymerase chain reaction (qPCR)-based assay to quantify the double-strand break reaction mediated by Cas9 RNP. To accomplish this, the dextransucrase gene (dsr) from Leuconostoc citreum was selected as the target DNA. The Cas9 protein was produced using recombinant Escherichia coli BL21, and two sgRNAs were synthesized through in vitro transcription to facilitate binding with the dsr gene. Under optimized in vitro conditions, the 2.6 kb dsr DNA was specifically cleaved into 1.1 and 1.5 kb fragments by both Cas9-sgRNA365 and Cas9-sgRNA433. By monitoring changes in dsr concentration using qPCR, the endonuclease activities of the two Cas9 RNPs were measured, and their efficiencies were compared. Specifically, the specific activities of dsr365RNP and dsr433RNP were 28.74 and 34.48 (unit/µg RNP), respectively. The versatility of this method was also verified using different target genes, uracil phosphoribosyl transferase (upp) gene, of Bifidobacterium bifidum and specific sgRNAs. The assay method was also utilized to determine the impact of high electrical field on Cas9 RNP activity during an efficient electroporation process. Overall, the results demonstrated that the qPCR-based method is an effective tool for measuring the endonuclease activity of Cas9 RNP.

Integrated genome-based assessment of safety and probiotic characteristics of Lactiplantibacillus plantarum PMO 08 isolated from kimchi.

Lactiplantibacillus plantarum PMO 08 has been used as a probiotic starter culture for plant-based fermented beverages, with various health-promoting effects such as cholesterol-lowering and anti-inflammatory activities. This study aimed to analyze the genome sequence of Lp. plantarum PMO 08 and identify its safety and probiotic characteristics at the genomic level. For this, complete genome sequencing was conducted to investigate the genes associated with risk and probiotic characteristics by using Pacbio combined with Illumina HiSeq. This bacterial strain has one circular chromosome of 3,247,789 bp with 44.5% G + C content and two plasmids of 50,296 bp with 39.0% G + C content and 19,592 bp with 40.5% G + C content. Orthologous average nucleotide identity analysis showed that PMO 08 belongs to the Lp. plantarum group with 99.14% similarity to Lp. plantarum WCFS1. No deleterious genes were determined in the virulence factor analysis, and no hemolysin activity or secondary bile salt synthesis were detected in vitro test. In the case of antibiotic resistance analysis, PMO 08 was resistant to ampicillin in vitro test, but these genes were not transferable. In addition, the strain showed same carbohydrate utilization with Lp. plantarum WCFS1, except for mannopyranoside, which only our strain can metabolize. The strain also harbors a gene for inositol monophosphatase family protein related with phytate hydrolysis and have several genes for metabolizing various carbohydrate which were rich in plant environment. Furthermore, in probiotic characteristics several genes involved in phenotypes such as acid/bile tolerance, adhesion ability, and oxidative stress response were detected in genome analysis. This study demonstrates that Lp. plantarum PMO 08 harbors several probiotic-related genes (with no deleterious genes) and is a suitable probiotic starter for plant-based fermentation.

Probiotic potential of Tetragenococcus halophilus EFEL7002 isolated from Korean soy Meju.

BACKGROUND: Probiotic starters can improve the flavor profile, texture, and health-promoting properties of fermented foods. Tetragenococcus halophilus is a halophilic lactic acid bacterium that is a candidate starter for high-salt fermented foods. However, the species is known to produce biogenic amines, which are associated with neurotoxicity. Here, we report a probiotic starter strain of T. halophilus, EFEL7002, that is suitable for use in high-salt fermentation. RESULTS: EFEL7002 was isolated from Korean meju (fermented soybean) and identified as T. halophilus, with 99.85% similarity. The strain is safe for use in food as it is a non-hemolytic and non-biogenic amine producer. EFEL7002 is tolerant to gastrointestinal conditions and can adhere to Caco-2 cells. This strain showed antioxidant, anti-inflammatory, and protective effects against the human gut epithelial barrier. EFEL7002 grew well in media containing 0-18% NaCl showing maximum cell densities in 6% or 12% NaCl. CONCLUSIONS: T. halophilus EFEL7002 can be used as a health-promoting probiotic starter culture for various salty fermented foods.

Co-packaging of opposing neurotransmitters in individual synaptic vesicles in the central nervous system.

Many mammalian neurons release multiple neurotransmitters to activate diverse classes of postsynaptic ionotropic receptors. Entopeduncular nucleus somatostatin (EP Sst+) projection neurons to the lateral habenula (LHb) release both glutamate and GABA, but it is unclear whether these are packaged into the same or segregated pools of synaptic vesicles. Here, we describe a method combining electrophysiology, spatially patterned optogenetics, and computational modeling designed to analyze the mechanism of glutamate/GABA co-release in mouse brain. We find that the properties of postsynaptic currents elicited in LHb neurons by optogenetically activating EP Sst+ terminals are only consistent with co-packaging of glutamate/GABA into individual vesicles. Furthermore, presynaptic neuromodulators that weaken EP Sst+ to LHb synapses maintain the co-packaging of glutamate/GABA while reducing vesicular release probability. Our approach is applicable to the study of multi-transmitter neurons throughout the brain, and our results constrain the mechanisms of neuromodulation and synaptic integration in LHb.

Analytical approaches to examine gamma-aminobutyric acid and glutamate vesicular co-packaging.

Multi-transmitter neurons, i.e., those that release more than one type of neurotransmitter, have been found in many organisms and brain areas. Given the peculiar biology of these cells, as well as the potential for diverse effects of each of the transmitters released, new tools, and approaches are necessary to parse the mechanisms and functions of synaptic co-transmission. Recently, we and others have studied neurons that project to the lateral habenula and release both gamma-aminobutyric acid (GABA) and glutamate, in some cases by packaging both transmitters in the same synaptic vesicles. Here, we discuss the main challenges with current electrophysiological approaches to studying the mechanisms of glutamate/GABA co-release, a novel statistical analysis that can identify co-packaging of neurotransmitters versus release from separate vesicle, and the implications of glutamate/GABA co-release for synapse function and plasticity.

Dynamics and Entropy of Cyclohexane Rings Control pH-Responsive Reactivity.

Activation entropy (ΔS ‡) is not normally considered the main factor in determining the reactivity of unimolecular reactions. Here, we report that the intramolecular degradation of six-membered ring compounds is mainly determined by the ΔS ‡, which is strongly influenced by the ring-flipping motion and substituent geometry. Starting from the unique difference between the pH-dependent degradation kinetics of geometric isomers of 1,2-cyclohexanecarboxylic acid amide (1,2-CHCAA), where only the cis isomer can readily degrade under weakly acidic conditions (pH < 5.5), we found that the difference originated from the large difference in ΔS ‡ of 16.02 cal·mol-1·K-1. While cis-1,2-CHCAA maintains a preference for the classical chair cyclohexane conformation, trans-1,2-CHCAA shows dynamic interconversion between the chair and twisted boat conformations, which was supported by both MD simulations and VT-NMR analysis. Steric repulsion between the bulky 1,2-substituents of the trans isomer is one of the main reasons for the reduced energy barrier between ring conformations that facilitates dynamic ring inversion motions. Consequently, the more dynamic trans isomer exhibits much a larger loss in entropy during the activation process due to the prepositioning of the reactant than the cis isomer, and the pH-dependent degradation of the trans isomer is effectively suppressed. When the ring inversion motion is inhibited by an additional methyl substituent on the cyclohexane ring, the pH degradability can be dramatically enhanced for even the trans isomer. This study shows a unique example in which spatial arrangement and dynamic properties can strongly influence molecular reactivity in unimolecular reactions, and it will be helpful for the future design of a reactive structure depending on dynamic conformational changes.

Limosilactobacillus fermentum MG7011: An Amylase and Phytase Producing Starter for the Preparation of Rice-Based Probiotic Beverages.

The goal of this study was to develop a starter strain of Limosilactobacillus fermentum which is beneficial for human health and suitable for rice fermentation. To achieve the goal, the characteristics of 25 strains of L. fermentum were compared in terms of health promoting potentials and rice fermenting abilities. L. fermentum MG7011 was selected as a superior strain to meet the required properties. First, as probiotic traits, the strain had tolerance to gastrointestinal conditions and ability to adhere to Caco-2 and HT-29 cells. The strain showed the antioxidative activity, anti-inflammatory activity, and a protective effect on the epithelial barrier. Next, as starter traits for rice fermentation, MG7011 exhibited proper fermentation profiles in rice solution, such as fast growth rate, pH and metabolite changes, amylase and phytase activities, and optimal viscosity changes for beverage. In conclusion, L. fermentum MG7011 has excellent probiotic activities and proper starter traits in rice, thereby it can be used as a suitable probiotic starter for rice fermentation.

Suitability Analysis of 17 Probiotic Type Strains of Lactic Acid Bacteria as Starter for Kimchi Fermentation.

The use of probiotic starters can improve the sensory and health-promoting properties of fermented foods. This study aimed to evaluate the suitability of probiotic lactic acid bacteria (LAB) as a starter for kimchi fermentation. Seventeen probiotic type strains were tested for their growth rates, volatile aroma compounds, metabolites, and sensory characteristics of kimchi, and their characteristics were compared to those of Leuconostoc (Le.) mesenteroides DRC 1506, a commercial kimchi starter. Among the tested strains, Limosilactobacillus fermentum, Limosilactobacillus reuteri, Lacticaseibacillus rhamnosus, Lacticaseibacillus paracasei, and Ligilactobacillus salivarius exhibited high or moderate growth rates in simulated kimchi juice (SKJ) at 37 °C and 15 °C. When these five strains were inoculated in kimchi and metabolite profiles were analyzed during fermentation using GC/MS and 1H-NMR, data from the principal component analysis (PCA) showed that L. fermentum and L. reuteri were highly correlated with Le. mesenteroides in concentrations of sugar, mannitol, lactate, acetate, and total volatile compounds. Sensory test results also indicated that these three strains showed similar sensory preferences. In conclusion, L. fermentum and L. reuteri can be considered potential candidates as probiotic starters or cocultures to develop health-promoting kimchi products.

Screening of endogenous strong promoters of Leuconostoc citreum EFEL2700 based on transcriptome analysis and its application for food-grade production of ß-galactosidase.

Leuconostoc citreum is a heterofermentative lactic acid bacterium frequently found in the various fermented foods. L. citreum EFEL2700 isolated from Korean kimchi has been used as a host strain for biotechnological applications. For the use as a food-grade host to over-produce food ingredients or enzymes, strong endogenous promoters guarantying high expression levels of target genes are necessary. In this study, transcriptomic analysis of L. citreum EFEL2700 was performed using RNA-Seq and three promoters of the most highly expressed genes were selected: glyceraldehyde 3-phosphate dehydrogenase (G3PD), 6-phosphogluconate dehydrogenase (6PGD), and phosphoketolase (PPK). Thereafter, they were used as promoters to express ß-galactosidase gene from Lactobacillus plantarum WCFS1 in L. citreum EFEL2700 and the levels were compared with the control promoter P710 from L. mesenteroides ATCC 8293. As results, the ß-galactosidase activities of the transformants were 2.73, 0.27, 37.43, and 9.25 units/mg under the P710, G3PD, 6PGD, and PPK promoters, respectively. The expression level of endogenous promoter 6PGD was superior to the heterologous P710 promoter previously used in a Leuconostoc-Escherichia coli shuttle vector. The 6PGD developed in this study can be used as the most suitable promoter for ß-galactosidase expression in L. citreum EFEL2700.

Lactobacillus pentosus SMB718 as a probiotic starter producing allyl mercaptan in garlic and onion-enriched fermentation.

Fermenting garlic and onion provides the advantages of storage life extension, anti-oxidative and anti-diabetic activities, and their metabolite, allyl mercaptan, offers a strong aroma and various health benefits. Here, we report the probiotic properties of Lactobacillus pentosus SMB718 isolated from Korean traditional paste and its high allyl mercaptan productivity in garlic and onion fermentation. This strain was safe for use in food fermentation, as it was a non-biogenic amine producer and non-hemolytic. It showed high stability under simulated human gastrointestinal conditions and good adhesion ability to intestinal epithelial cells, including both Caco-2 and HT-29. This strain had antioxidant and anti-microbial activities. In addition, the heat-killed cells and lysate exerted anti-inflammatory effects on both LPS-stimulated RAW 264.7 cells and mouse macrophages by inhibition of pro-inflammatory cytokines and induction of anti-inflammatory cytokines. Furthermore, this strain possessed good fermentation properties in garlic and onion-enriched radish juice (GORJ); it grew well decreasing the pH and provided a rich aroma compound during fermentation. When L. pentosus SMB718 was used as a starter in garlic and onion fermentation, a significantly higher amount of allyl mercaptan (344 ppb) was produced compared with that produced by the type strain (82 ppb). In conclusion, L. pentosus SMB718 can be used as a beneficial probiotic starter for better flavor production in the fermentation of allium species plants.

Whole-Genome Sequence of Lactobacillus plantarum SPC-SNU 72-2 as a Probiotic Starter for Sourdough Fermentation.

We report the whole-genome sequence of Lactobacillus plantarum SPC-SNU 72-2, a probiotic starter for sourdough. Genome sequencing was completed using the Pacific Biosciences RS II and Illumina platforms. This study will facilitate the understanding of microbial characteristics of L. plantarum SPC-SNU 72-2 and its roles during sourdough fermentation.

Covalently Grafted 2-Methacryloyloxyethyl Phosphorylcholine Networks Inhibit Fibrous Capsule Formation around Silicone Breast Implants in a Porcine Model.

The surface of human silicone breast implants is covalently grafted at a high density with a 2-methacryloyloxyethyl phosphorylcholine (MPC)-based polymer. Addition of cross-linkers is essential for enhancing the density and mechanical durability of the MPC graft. The MPC graft strongly inhibits not only adsorption but also the conformational deformation of fibrinogen, resulting in the exposure of a buried amino acid sequence, γ377-395, which is recognized by inflammatory cells. Furthermore, the numbers of adhered macrophages and the amounts of released cytokines (MIP-1α, MIP-1ß, IL-8, TNFα, IL-1α, IL-1ß, and IL-10) are dramatically decreased when the MPC network is introduced at a high density on the silicone surface (cross-linked PMPC-silicone). We insert the MPC-grafted human silicone breast implants into Yorkshire pigs to analyze the in vivo effect of the MPC graft on the capsular formation around the implants. After 6 month implantation, marked reductions of inflammatory cell recruitment, inflammatory-related proteins (TGF-ß and myeloperoxidase), a myoblast marker (α-smooth muscle actin), vascularity-related factors (blood vessels and VEGF), and, most importantly, capsular thickness are observed on the cross-linked PMPC-silicone. We propose a mechanism of the MPC grafting effect on fibrous capsular formation around silicone implants on the basis of the in vitro and in vivo results.

Bacterial and fungal diversity in Laphet, traditional fermented tea leaves in Myanmar, analyzed by culturing, DNA amplicon-based sequencing, and PCR-DGGE methods.

Laphet is a traditional fermented food in Myanmar, made from tea leaves (Camellia sinensis) by fermentation with limited air passage. We performed microbial diversity analyses on 14 Laphet products collected from different locations in Myanmar. Amplicon-based sequencing results revealed Lactobacillus and Acetobacter were abundant bacteria and Candida, Pichia, Cyberlindnera, and Debaryomyces were abundant yeast. Using selective media, eight species of lactic acid bacteria and nine species of yeast were isolated; Lactobacillus plantarum and L. collinoides were dominant bacteria and Pichia manshurica, Candida boidinii, and Cyberlindnera jadinii were major yeasts. PCR-DGGE analysis confirmed that most of the dominant bacterial and yeast species found in culture dependent analysis were present in Laphet samples. Microbial diversity and pH of Laphet were different between samples from tea plantation area and local markets due to possible differences in incubation time periods. When tannase activity was tested, 23 among 29 bacterial isolates and two among 36 yeast isolates showed positive activities. These findings provide new insights into microbial diversity of Laphet and increased our understanding of the core bacterial and yeast species involved in the manufacture of Laphet.

Efficient reduction of fibrous capsule formation around silicone breast implants densely grafted with 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers by heat-induced polymerization.

Implants based on silicone elastomers, polydimethylsiloxane (PDMS), have been widely used for breast augmentation and reconstruction, but excessive foreign body reactions around implants often cause serious side effects such as capsular contracture. In our previous study, we covalently grafted 2-methacryloyloxyethyl phosphorylcholine (MPC)-based polymers on the surface of PDMS blocks by UV-induced polymerization and showed effective reduction of capsular formation around the MPC-grafted PDMS in rats. In the present study, we examined the efficacy of heat-induced polymerization of MPC grafting on silicone breast implants intended for humans, and analyzed the in vivo inhibitory effect against capsular formation and inflammation in pigs, which are closely related to humans in terms of epidermal structures and fibrotic processes. The heat-induced polymerization provided a thicker MPC-grafted surface and was more effective than UV-induced polymerization for the grafting of complex shaped non-transparent implants. After 24-week implantation in the submuscular pockets of Yorkshire pigs, the heat-induced MPC-grafted breast implants showed 45% smaller capsular thickness and 20-30% lower levels of inflammatory markers such as myeloperoxidase (MPO), transforming growth factor-ß (TGF-ß), and α-smooth muscle actin (α-SMA) in surrounding tissues compared to non-grafted implants. This study provides important information for future clinical trials of MPC-grafted silicone implants.

In Vitro and In Vivo Antimicrobial Activity of Antibiotic-Conjugated Carriers with Rapid pH-Responsive Release Kinetics.

Two representative antibiotics, cephradine (CP) and moxifloxacin (MX), are covalently conjugated with a ß-cyclodextrin (ß-CD)-based carrier via pH-responsive 1-methyl-2-(2'-carboxyethyl) maleic acid amide (MCM) linkers with excellent conjugation efficiency via simple mixing. At pH 5.5, 90% and 80% of the CP and MX, respectively, are released from the carriers within 30 min, in contrast with the much-delayed release profile at pH 7.4. The in vitro inhibitory effect of ß-CD-MCM-CP on the growth of Staphylococcus aureus is significantly lower than that of free CP at pH 7.4, but it reaches the level of free CP at pH 5.5. Moreover, S. aureus develops significant CP resistance after pretreatment with free CP, whereas the initial CP sensitivity is maintained after pretreatment with ß-CD-MCM-CP at pH 7.4. However, ß-CD-MCM-MX exhibits no such pH-responsive activity against Bacteroides fragilis, probably due to the insufficient stability of the MX conjugation at pH 7.4. In nondiabetic and diabetic mouse models, ß-CD-MCM-CP significantly reduces the subcutaneous abscess scores and the bacterial counts in the abscess, although this represents only a marginal improvement in antimicrobial activity compared to free CP.

Development of Freeze-Thaw Tolerant Lactobacillus rhamnosus GG by Adaptive Laboratory Evolution.

The industrial application of microorganisms as starters or probiotics requires their preservation to assure viability and metabolic activity. Freezing is routinely used for this purpose, but the cold damage caused by ice crystal formation may result in severe decrease in microbial activity. In this study, adaptive laboratory evolution (ALE) technique was applied to a lactic acid bacterium to select tolerant strains against freezing and thawing stresses. Lactobacillus rhamnosus GG was subjected to freeze-thaw-growth (FTG) for 150 cycles with four replicates. After 150 cycles, FTG-evolved mutants showed improved fitness (survival rates), faster growth rate, and shortened lag phase than those of the ancestor. Genome sequencing analysis of two evolved mutants showed genetic variants at distant loci in six genes and one intergenic space. Loss-of-function mutations were thought to alter the structure of the microbial cell membrane (one insertion in cls), peptidoglycan (two missense mutations in dacA and murQ), and capsular polysaccharides (one missense mutation in wze), resulting in an increase in cellular fluidity. Consequently, L. rhamnosus GG was successfully evolved into stress-tolerant mutants using FTG-ALE in a concerted mode at distal loci of DNA. This study reports for the first time the functioning of dacA and murQ in freeze-thaw sensitivity of cells and demonstrates that simple treatment of ALE designed appropriately can lead to an intelligent genetic changes at multiple target genes in the host microbial cell.

Complete genome sequence of Leuconostoc citreum EFEL2700, a host strain for transformation of pCB vectors.

Leuconostoc citreum is an important lactic acid bacterium used as a starter culture for producing kimchi, the traditional Korean fermented vegetables. An efficient host strain for plasmid transformation, L. citreum EFEL2700, was isolated from kimchi, and it has been frequently used for genetic engineering of L. citreum. In this study, we report the whole genome sequence of the strain and its genetic characteristics. Genome assembly yielded 5 contigs (1 chromosome and 4 plasmids), and the complete genome contained 1,923,830 base pairs (bp) with a G + C content of 39.0%. Average nucleotide identity analysis showed high homology (≥ 99%) to the reference strain L. citreum KM 20. The smallest plasmid (4.3 kbp) was used as an Escherichia coli shuttle vector (pCB) for heterologous gene expression, and L. citreum EFEL2700 showed the highest transformation efficiency, 6.7 × 104 CFU µg-1 DNA. Genetic analysis of the genome enabled the construction of primary metabolic pathway showing a typical hetero-type lactic acid fermentation. Notably, no core genes for primary metabolism were observed in plasmid 4 and it could be eliminated to create an efficient host for gene transformation. This report will facilitate the understanding and application of L. citreum EFEL2700 as a food-grade microbial cell factory.