Leuconostoc Citreum Research Articles

Elucidating core microbiota in yellow wine (Huangjiu) through flavor-oriented synthesis and construction of microbial communities

Huangjiu, a traditional Chinese alcoholic beverage with a history spanning thousands of years, holds significant cultural and economic value in China. Despite its importance, the complexity of Huangjiu fermentation and the intricate interactions within its microbial community remain underexplored. This study addresses this gap by identifying the core volatile organic compounds (VOCs) and key microorganisms that define the flavor profile of Huangjiu. We employed HS-SPME-GC–MS along with aroma reconstitution and omission experiments to identify core VOCs, including Isobutanol, Isoamyl alcohol, β-Phenylethanol, and others. Metagenomic sequencing combined with QPCR was used to analyze microbial communities, revealing the temporal and spatial dynamics during fermentation. A synthetic microbial community model was constructed using the core microbes identified: Saccharomyces cerevisiae, Lactobacillus brevis, Saccharopolyspora rectivirgula, Bacillus subtilis, Leuconostoc citreum, Lactobacillus plantarum, Lactobacillus curvatus, Lactobacillus casei, and Aspergillus oryzae. This model successfully replicated Huangjiu’s core VOCs and sensory characteristics, increased alcohol content, and reduced acidity. Our study contributes valuable insights into the microbial influences on Huangjiu quality, paving the way for its enhanced production and providing a foundation for future research in fermented beverages.

Bacterial Community of Breast Milk in Breastfeeding Women Using Culture-Dependent and Culture-Independent Approaches.

This study aimed to analyze bacterial communities in breast milk obtained from five breastfeeding women. Culture-dependent and culture-independent methods were used to analyze microbial communities. Total bacterial count of breast milk determined using plate count agar ranged from 3.3 × 104 ± 3.5 × 102 colony forming unit (CFU)/g to 1.7 × 105 ± 3.5 × 103 CFU/g, with a pH between 6.4 and 6.8. Only three species, Leuconostoc citreum (17 out of 160 strains; 10.63%), Staphylococcus epidermidis (118 strains; 73.75%), and Staphylococcus lugdunensis (25 strains; 15.63%), belong to the phylum Bacillota were detected by culture-dependent analysis. Microbial communities analyzed via pyrosequencing revealed greater diversity compared to the culture-dependent analysis. At the phylum level, Bacillota accounted for 60.9% of the microbial community. At the genus level, Staphylococcus (24.57%), Streptococcus (22.93%), and Methylobacterium (8.76%) were dominant genera. While pyrosequencing demonstrated greater microbial diversity than the agar plate culture method, identified microbes might lack information or include many unculturable microbes. Most of all, considering the low total bacterial count averaging 7.2 × 104 CFU/g, further research is needed to determine the significance of microbial presence in breast milk.

Exploring the role of the residues into catalytic cavity of inulosucrase from Leuconostoc citreum CW28

Inulosucrases are enzymes capable of synthesizing inulin polymers using sucrose as the main substrate. The enzymatic activity relies on the catalytic triad within the active site and residues responsible for substrate recognition and orientation, termed carbohydrate-binding subsites. This study investigates the role of specific residues within the catalytic cavity of a truncated version of IslA4 in enzymatic catalysis. Mutants at residues S425, L499, A602, R618, F619, Y676, Y692, and R696 were constructed and characterized. Characterization results, and in silico structural comparison with other fructansucrases, reveal these residues' functional significance in catalysis. Residue S425 belongs to subsite −1; residues R618 and Y692 are part of subsite +1, and residue R696 belongs to subsites +1 and +2. Residues L499 and A602 are support residues; the former favors the formation of the fructosyl-enzyme intermediate, while the latter stabilizes the acid/base catalyst during catalysis. Residues Y676 and F619 may participate in stabilizing residues at −1/+1 subsites. This study represents the first comprehensive exploration of the structural determinants essential for enzymatic function in the inulosucrase of Leuconostoc citreum, and proposes the identity of residues involved in the −1 to +2 subsites.

Genomic and phenotypic analysis unveiling the carbohydrate metabolic characteristics of Leuconostoc citreum SH12 in plant-based fermentation

Leuconostoc citreum has been widely utilized for industrial fermentation. Previously, we found Leuc. citreum SH12 as a starter culture, exhibited superior fermentation characteristics in plant-based food, but its genomic, evolutionary and carbohydrate metabolic features remained unclear. This study aimed to reveal the metabolic characteristics of Leuc. citreum SH12 in response to various carbon sources by genomic and phenotypic analysis. By multiple sequencing technology, we assembled the 1.84 Mb complete genome of Leuc. citreum SH12 and identified 193 carbohydrate metabolism genes involved in the KEGG annotation, including 59 carbohydrate-active enzymes (CAZymes) genes. Comparative genome analysis indicated that Leuc. citreum SH12 had carbohydrate metabolism pathways similar to other Leuc. citreum, but it had 27 specific genes annotated as ABC transporters and hypothetical proteins, probably representing great resilience to the environment. The reconstruction of carbohydrate metabolic pathways and carbon utilization tests showed that Leuc. citreum SH12 could metabolize glucose, sucrose, fructose and maltose well, followed by xylose, arabinose, mannose and cellobiose, but could not utilize galactose, lactose, raffinose and stachyose. Soymilk fermentation test indicated that the strain could produce mannitol, and water-soluble and water-insoluble α-glucans. This study provided insights into a deeper understanding of the genomic and carbohydrate metabolic characteristics of Leuc. citreum SH12, and implied its potential application in plant-based fermented food.

Microbial Community Dynamics and Metabolite Changes during Wheat Starch Slurry Fermentation.

Wheat starch fermentation slurry is the main substrate for producing Ganmianpi, a traditional Chinese fermented wheat starch-based noodle. In the present work, the microbial population dynamics and metabolite changes in wheat starch fermentation slurry at different fermentation times (0, 1, 2, 3, and 4 days) were measured by using high-throughput sequencing analysis and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-MS) methods. The texture and sensory properties of Ganmianpi made from fermented starch slurry are also evaluated. The results showed that Latilactobacillus curvatus and Leuconostoc citreum were the dominant bacteria in wheat starch fermentation slurry, while Saccharomyces cerevisiae and Kazachstania wufongensis were identified as the main species of fungi. With the extension of fermentation time, the reducing sugar content first increased and then decreased, when the titratable acidity content showed an increasing trend, and the nonvolatile acid was significantly higher than the volatile acid. A total of 62 volatile flavor compounds were identified, and the highest content is alcohols, followed by acids. Fermentation significantly reduced the hardness and chewiness of Ganmianpi, and increased its resilience and cohesiveness. Ganmianpi made from fermented starch slurry for two and three days showed a higher sensory score than other samples. The present study is expected to provide a theoretical basis for exploiting the strains with potential for commercial application as starter cultures and quality improvement of Ganmianpi.

Thermal Treatment and Fermentation of Legume Flours with Leuconostoc citreum TR116 for the Development of Spreadable Meat Alternatives

The demand for meat alternatives in different forms is increasing due to consumers’ awareness of climate change and the health benefits of plant-based ingredients compared to animals. However, current alternatives on the market do not fulfil consumers’ acceptance for taste and texture. Hence, different physical and biological processes, such as thermal treatment and fermentation, need to be investigated. This study reveals that the thermal treatment of legume flours (soy, pea and lentil) prior to single-strain fermentation with Leuconostoc citreum TR116 has a major impact on acidification, colour, texture and sensory properties due to the pregelatinisation of starch and denaturation of proteins. The thermal treatment of soy flour resulted in liquification, and it could not be used as a fermentation substrate. However, non-heat-treated soy flour was fermented for comparison. The highest total titratable acidity (TTA) was determined in fermented pea flour (PF) and fermented lentil flour (LF) after 48 h with 24.35 ± 0.29 mL 0.1 M NaOH/10 g and 24.98 ± 0.33 mL 0.1 M NaOH/10 g, respectively. Heat treatment prior to fermentation led to a reduction in TTA by 20 mL 0.1 M NaOH/10 g for both PF and LF. The loss of colour pigments during thermal treatment led to a lighter colour of the spreadable alternatives. Moreover, a harder texture (+13.76 N in LF; +15.13 N in PF) and a lower adhesiveness (−0.88 N in LF; −0.43 N in PF) were detected in spreadable meat alternatives that were treated with heat prior to fermentation. Cohesiveness was decreased by thermal treatment, and fermentation did not impact it. Fermentation without pre-heat treatment increased adhesiveness by 4.37 N in LF and by 2.36 N in PF—an attribute typical for spreadable meat. Descriptive sensory analysis showed that thermal treatment significantly decreased bitterness but increased crumbliness and reduced juiciness. On the other hand, fermentation without pre-heat treatment mainly influenced flavour by increasing fruitiness and decreasing beaniness, earthiness and off-flavours. In summary, thermal treatment prior to fermentation is powerful in reducing legume-typical off-flavours but is not suitable for the development of spreadable meat alternatives due to texture changes. However, this process can be very beneficial when producing sausage-like alternatives.

Synthesis of dextran of different molecular weights by recombinant dextransucrase DsrB

Leuconostoc citreum JZ-002 was extracted from artisanal orange wine. This strain was used to synthesize dextran with a purification extraction of 27.9 g/L. The resulting dextran had a molecular weight of 2.45 × 106 Da. A significant portion, amounting to 64 % of the structure, is constituted by the main chain, with α-(1,6) glycosidic bonds acting as the linkages. In contrast, the branched chain, comprising 34 % of the entire molecule, is characterized by the presence of α-(1,3) glycosidic bonds. The dextransucrase DsrB, believed to be accountable for the formation of the dextran backbone, was successfully cloned into the pET-28a-AcmA vector. The recombinant expression of the enzyme was achieved. Purified recombinant enzymes and immobilized in a single go using the gram-positive enhancer matrix (GEM). The maximum yield of dextran produced by suchimmobilized enzyme was 191.9 g/L. The composition featured a dextran connected via α-(1,6) glycosidic linkages. Molecular weight controlled synthesis was achieved with sucrose concentrations of 100–2000 mM and enzyme concentrations of 320–1280 U. The Mw of the synthesized dextran extended from 4680 to 1,320,000 Da. By controlling the ratio between enzyme concentration and sucrose concentration, dextrans with diverse Mw can be enzymatically generated.

Screening of lactic acid bacteria with the ability to reduce goaty flavor related fatty acids in goat milk

In this study, we conducted sensory evaluation and gas chromatography–mass spectrometry analysis on fermented goat milk samples prepared by 12 strains of lactic acid bacteria (LAB) isolated from goat milk to screen for strains with the ability to reduce the goaty flavor. The bacterial counts of fermented goat milk was 7.07–9.01 log CFU/mL. The electronic nose distinguished fresh goat milk (FGM) and fermented goat milk, and the electronic tongue results showed that Leuconostoc citreum 1, 4, 20, 22, 32, and 57, Latilactobacillus curvatus 144 and 147 imparted fermented goat milk a taste different from FGM. Overall, Leuconostoc citreum 57, Leuconostoc citreum 126, Latilactobacillus curvatus 142, Latilactobacillus curvatus 143, and Latilactobacillus curvatus 147 were screened with the ability to improve the flavor of goat milk. They gave fermented goat milk a goat flavor score lower than or equal to FGM. And the fermented goat milk samples 57, 126, 142, 143, and 147 contained 25, 22, 15, 24, and 17 volatile flavor compounds, respectively, with a greater variety and content of ketones and aldehydes and lower levels of hexanoic acid, octanoic acid, and decanoic acid than FGM. However, the pH and WHC results indicated that the application of these strains as secondary cultures is necessary. Our finding provides basic research data to improve the flavor of goat milk products.

Isolation and characterization of beneficial bacteria from <i>Apis Cerana</i> honeybees from Hanoi, Vietnam

Beneficial bacteria are vital for maintaining honeybee health by outcompeting pathogenic microorganisms, boosting immunity, and enhancing resilience to diseases. Identifying the specific bacterial strains associated with honeybees enables the development of targeted probiotics that can improve the health of bees and humans. The present study describes the isolation and identification of bacterial strains from Apis cerana honeybees in Hanoi, Vietnam, utilizing a culture-based method, Matrix-Assisted Laser Desorption-Ionization Time of Flight Mass Spectrometry (MALDI-TOF) analysis, and 16S rRNA sequencing. MALDI-TOF analysis revealed several beneficial bacterial species, including Lactobacillus kunkeei, Lactobacillus plantarum, Pediococcus pentosaceus, Leuconostoc mesenteroides, Leuconostoc citreum, Bacillus subtilis, and Bacillus megaterium. Antimicrobial spectrum analysis showed that 16 out of the 23 identified isolates exhibited inhibitory effects against tested bacteria. Selected isolates with broad antimicrobial spectra, including L. kunkeei, L. plantarum, P. pentosaceus, L. mesenteroides, L. citreum, and B. subtilis, were further validated through 16S rRNA gene sequencing. The results confirmed the identity of these strains, emphasizing the probiotic potential of L. kunkeei, L. plantarum, L. mesenteroides, L. citreum, P. pentosaceus, and B. subtilis for honeybee health. Our findings provide valuable insights into the bacterial diversity and antimicrobial properties associated with honeybees, suggesting their use as probiotics in beekeeping and beyond.

Actinobacteria diversity associated with sponge Amorphinopsis exacavans from Rancabuaya Beach, Garut, Indonesia

Abstract Sponges are complex marine organisms known for their symbiotic relationships with various bacterial communities, which play structural and functional roles within the sponge holobiont. Actinobacteria have received much attention because of their potential pharmaceutical applications. This study examines Amorphinopsis excavans profile, distinguishing between endosymbionts and ectosymbionts. The microbial grouping was characterized using Next Generation Sequencing (NGS) anchored to the 16S rRNA marker. The results showed that Proteobacteria and Firmicutes dominated both the endosymbiont and ectosymbiont communities at the phylum level. The actinobacterial diversity index at the genus level in both communities was 2.77 and 3.11, indicating moderate to high diversity without a dominant genus. For the genus level, the evenness scores of 0.81 and 0.89 indicated a high population type within the bacterial community. Relative abundance revealed the three most prevalent genera in the endosymbiont community were Rothia, Thermoplyspora, and Thermomonospora. In contrast, Kocuria, Mycobacterium, and Bifidobacterium were the three most common genera of ectosymbionts. Leuconostoc citreum was the first species known to be associated with a sponge. This study is a developing metagenomic assessment of actinobacterial diversity in A. excavans, providing novel insights into the sponge’s complex microbial ecosystem.

The species and abundance of gut bacteria both positively impact Phortica okadai behavior

BackgroundGut bacteria, which serve as essential modulators, exert a significant impact on insect physiology and behavior and have substantial application potential in pest management. The dynamics of gut bacteria and their impact on Phortica okadai behavior remain unclear.MethodsIn this study, the dynamics of gut bacteria at different developmental stages in P. okadai were analyzed using 16S ribosomal RNA (rRNA) gene sequencing, and the species and abundance of gut bacteria that affect host behavior were examined via behavioral experiments.ResultsA total of 19 phyla, 29 classes, 74 orders, 101 species, and 169 genera were identified. The results of the behavioral experiments indicated that the species Lactiplantibacillus argentoratensis, Acetobacter tropicalis, Leuconostoc citreum, and Levilactobacillus brevis effectively influenced the feeding preference of P. okadai, and the single-bacterium-seeded P. okadai exhibited feeding preferences distinct from those of the germ-free (GF) and wild-type P. okadai.ConclusionsThe species and relative abundance of gut bacteria together positively impact P. okadai behavior. Lactiplantibacillus argentoratensis, as the most attractive bacteria to P. okadai, presents opportunities for novel pest control strategies targeting this vector and agricultural pest.Graphical

Comparison of the quality of suansun product between starter inoculation and natural fermentation

Suansun (fermented bamboo shoots) was prepared by natural fermentation (NF) and inoculation fermentation (IF) with a starter culture containing Lactococcus lactis, Leuconostoc citreum, and Lactiplantibacillus plantarum in this study, to evaluate the effects of inoculation mixed starter culture on physicochemical, flavor and sensory characteristics of suansun. The results showed that IF suansun acidified faster and to a greater extent than NF. Besides, the accelerated acidification process significantly decreased the nitrite content, shortened the fermentation time and improved the food safety of the final suansun product in IF. At the end of fermentation, the lactic acid concentration was significantly higher in IF (6.17 ± 0.25 g/L) than in NF (3.83 ± 0.28 g/L). Twenty-seven volatile compounds were identified as the characteristic flavor compounds in suansun and the relative content of nonanal, hexanal, 1-octen-3-ol and 3-octanone (ROAV >1) was higher in IF than in NF at the late stage of fermentation. In addition, 132 non-volatile compounds were identified as significant differential metabolites, which were mainly small peptides and fatty acids in both NF and IF. Sensory evaluation found that the aroma, taste, texture and overall quality scores of IF suansun were all superior to those of NF suansun. The above results demonstrated that the use of mixed starter cultures of Lac. lactis, Leu. citreum, and L. plantarum contributed to improving the quality of suansun product, and might provide a feasible approach for standardized production of suansun in the future.

PROBIOTIC MICROORGANISMS IN BREAD SOURDOUGHS

The review allows for characterization and evaluation of the typical microbiota and probiotic properties of individual species isolated from various bread sourdoughs. It has been observed that an interest in using sourdoughs for bread making and studying their microbiota has been steadily increasing in recent years. However, an analysis of contemporary publications has revealed insufficient information regarding microorganisms characteristic of sourdoughs based on spelt, buckwheat, corn, rice, teff, amaranth, quinoa, barley, oats, chia, sorghum, beans, and peas. The most studied sourdoughs are those based on wheat and rye flour. A list of the most prevalent lactic acid bacteria (LAB) and yeasts isolated from sourdoughs has been established. It comprises Companilactobacillus paralimentarius, Fructilactobacillus sanfranciscensis, Lactiplantibacillus plantarum, Latilactobacillus sakei, Leuconostoc citreum, Levilactobacillus brevis, Pediococcus pentosaceus, Weissella cibaria, Weissella confusa, as well as Kazachstania humilis, Kazachstania unispora, Pichia kudriavzevii, Pichia fermentans, Saccharomyces cerevisiae and Wickerhamomyces anomalus. All typical mentions of the probiotic properties of microorganisms isolated from bread sourdoughs have been described. When isolating probiotics from bread sourdoughs, special attention should be paid to such species of LAB as Lactiplantibacillus plantarum, Levilactobacillus brevis, Pediococcus pentosaceus, Enterococcus faecium, as well as the yeasts Saccharomyces cerevisiae and Kazachstania humilis, as they are quite commonly found in sourdoughs from various types of flour and have the most conspicuous probiotic properties. According to the review, it has been established that stress tolerance and antimicrobial activity are typical probiotic properties for microorganisms isolated from sourdoughs, although antioxidant properties require further research. Advances in technology and increased economic accessibility will lead to increased demand for new probiotic strains and microorganisms from bread sourdoughs and may help meet new levels of consumer needs.

Genomic insights into antibiotic resistance genes in Leuconostoc citreum strains isolated from artisanal buffalo milk curd in Bangladesh through whole-genome sequencing.

We sequenced the genome of Leuconostoc citreum strains BSMRAU-M1L6 and BSMRAU-M1L13 isolated from artisanal buffalo milk curd in Bangladesh. The draft genomes of BSMRAU-M1L6 and BSMRAU-M1L13 are 1,869,891 and 1,890,611 bp, respectively, with 50.0× coverage (both) and 65 and 75 contigs, respectively.

Trichuris trichiura infection is associated with changes in gut microbiome composition and function among women of reproductive age from Pemba, Tanzania

Large intestine-dwelling helminths affect microbiome composition. In sub-Saharan Africa, where helminth infections are endemic, the use of chemotherapeutic drugs is the primary strategy for controlling soil-transmitted helminthiases (STHs). However, the emergence of anthelmintic resistance necessitates the urgent exploration of alternative and complementary treatments to achieve the World Health Organization’s goal of eliminating STHs. One promising avenue involves the manipulation of gut microbiota in at-risk populations. This study aimed to enhance the understanding of the interplay between Trichuris trichiura and the gut microbiome. In this study, we used the Mini-FLOTAC technique for parasitological analyses and a shotgun metagenomic sequencing approach to investigate the effect of T. trichiura on the gut microbiome by comparing infected and non-infected women of reproductive age (WRA) from Pemba. Structural and functional analyses of the gut microbiome revealed that T. trichiura infection shaped the host gut microbiome in WRA. Some taxa vary according to infection status. Prevotella genus was more abundant in healthy participants, whereas species such as Weissella cibaria, Leuconostoc citreum (new emergent probiotics), and Leuconostoc lactis (starter) decreased in infected individuals, suggesting the use of potential probiotic treatments to mitigate dysbiosis induced by STHs. Furthermore, the overall number of common fungi, irrespective of species, was significantly higher in the mycobiome of Trichuris infected participants. Functional analysis revealed significant differences in metabolic pathways (p < 0.05), with cholesterol metabolism and pathogenic infections being more abundant in the infected samples than in the non-infected samples. In conclusion, this study sheds light on the intricate interactions between helminth infections and the gut microbiome in the WRA, particularly in STH-endemic regions. The identified associations between specific gut microbial changes and T. trichiura infection may pave the way for innovative complementary treatments to effectively combat STHs.

Microbial characterization of Sichuan Baoning vinegar: lactic acid bacteria, acetic acid bacteria and yeasts.

Sichuan Baoning vinegar, a typical representative of Sichuan bran vinegar, is a famous traditional fermented food made from cereals in China. At present, there are few studies on microbial characterization of culturable microorganisms in solid-state fermentation of Sichuan bran vinegar. To comprehensively understand the diversity of lactic acid bacteria, acetic acid bacteria and yeasts, which play an important role in the fermentation of Sichuan bran vinegar, traditional culture-dependent methods combined with morphological, biochemical, and molecular identification techniques were employed to screen and identify these isolates. A total of 34 lactic acid bacteria isolates, 39 acetic acid bacteria isolates, and 48 yeast isolates were obtained. Lactic acid bacteria were dominated by Enterococcus durans, Leuconostoc citreum, Lactococcus lactis, and Lactiplantibacillus plantarum, respectively. Latilactobacillus sakei was the first discovery in cereal vinegar. Acetic acid bacteria were mainly Acetobacter pomorum and A. pasteurianus. The dominant yeast isolates were Saccharomyces cerevisiae, in addition to four non-Saccharomyces yeasts. DNA fingerprinting revealed that isolates belonging to the same species exhibited intraspecific diversity, and there were differences between phenotypic and genotypic classification results. This study further enriches studies on cereal vinegar and lays a foundation for the development of vinegar starters.

Selection of lactic acid bacteria from home-made sourdoughs for resistance to the main almond skin polyphenols

The aim of this research was to identify lactic acid bacteria (LAB) that could be used as starter strains in sourdough made with almond peel powder to create novel fermented functional bakery products. Physicochemical characteristics and LAB were analyzed from ten home-made sourdoughs used at the family level in western Sicily (Italy). The pH (3.57–4.80) and TTA (8.20–14.20 mL 0.1 N NaOH/10 g) were inversely correlated. LAB dominated all sourdoughs, and the highest cell densities (6.74–9.28 log cfu/g) were detected on the medium Sour Dough Bacteria, except for one sample. Among LAB groups, the lowest counts (4.92–6.19 log cfu/g) were obtained on M17 used for LAB cocci. Yeasts were lower than LAB from two to four orders of magnitude with values between 3.93 and 6.11 log cfu/g. Twenty strains belonging to the species Enterococcus gilvus, Fructilactobacillus sanfranciscensis, Lacticaseibacillus paracasei, Lactiplantibacillus pentosus, Lactiplantibacillus plantarum, Lactococcus lactis, Lentilactobacillus buchneri, Lentilactobacillus diolivorans, Leuconostoc citreum, Leuconostoc holzapfelii, Levilactobacillus brevis, Pediococcus pentosaceus, and Weissella cibaria were identified. Eleven out of the 20 strains identified showed the ability to grow in presence of 16 polyphenols characterizing the peel of almonds. Eight of these LAB strains dropped pH below 4.5 after 6–8 h of fermentation, and two strains showed a strong inhibitory effect against Listeria monocytogenes ATCC19114 with inhibition diameters around the wells >19 mm. Thus, all acidifying strains were selected to produce sourdough bakery goods enriched with almond skin powder.

Effects of substrates and suppliers of ingredients on microbial community and metabolites of traditional non-salt Suancai.

Aim: Non-salt Suancai is an acidic fermented vegetable consumed by the Chinese Yi ethnic group. Traditionally, it is produced by fermentation without salt in a cold environment. The present study aimed to investigate the metabolite and microbial characteristics, and the effects of substrates/suppliers ingredients on non-salt Suancai. Methods: A simulated fermentation system of non-salt Suancai was constructed by using different substrates/suppliers' ingredients. The coherence and differential detection of the metabolite and microbial characteristics were done through non-target metabolomic and metagenomic analysis. Results: Lactic acid was the predominant organic acid across all samples. The enumeration of the Lactic acid bacteria showed no discernible differences between study groups, but that of yeast was highest in the mustard leaf stem (Brassica juncea var. latipa). The three major biological metabolic pathways were metabolism, environmental information, and genetic information processing based on the KEGG database. The metabolite diversity varied with the substrate/supplier of ingredients based on the PLS-DA plot. Lactiplantibacillus, Leuconostoc, and Lactococcus were prevalent in all samples but differentially. The microbial diversity and richness varied significantly, with 36~291 species being identified. Among the various substrates collected from the same supplier, 29, 59, and 29 differential species were identified based on LEfSe [linear discriminant analysis (LDA) > 2, P < 0.05]. Leuconostoc citreum, Leuconostoc mesenteroides, Leuconostoc pseudomesenteroides, Lactiplantibacillus plantarum, and Leuconostoc lactis were likely to be used as the species to discriminate samples collected from different suppliers. Conclusions: This research contributed to the exploration of microbial and metabolite characteristics behind the ingredient restriction of non-salt Suancai using traditional technology.

Lot-to-lot variation in the microbiota during the brewing process of kimoto-type Japanese rice wine.

Kimoto-type Japanese rice wine (sake) has a wide variety of flavors, as the predominant microbes, including lactic acid bacteria (LAB) and nitrate-reducing bacteria, that spontaneously proliferate in the fermentation starter vary depending on the brewery. In this study, we traced the microbiota in four lots of starters manufactured in a newly established brewery and evaluated the lot-to-lot variation and characteristics of the microbiota in the brewery. The results of a 16S ribosomal RNA amplicon analysis showed that the starters brewed in the second brewing year had a more diverse microbiota than those in the first brewing year. Among the LAB predominated at the middle production stage, lactococci, including Leuconostoc spp., were detected in all the lots, while lactobacilli predominated for the first time in the second year. These results suggest that repeated brewing increased microbial diversity and altered the microbial transition pattern in the kimoto-style fermentation starters. Phylogenetic analyses for the LAB isolates from each starter identified Leuconostoc suionicum, Leuconostoc citreum, and Leuconostoc mesenteroides as predominant lactococci as well as a unique lactobacillus in place of Latilactobacillus sakei. We also found that a rice koji-derived Staphylococcus gallinarum with nitrate-reducing activity was generally predominant during the early production stage, suggesting that there was a case in which staphylococci played a role in nitrite production in the starters. These findings are expected to contribute to the understanding of the diversity of microbiota in kimoto-type sake brewing and enable control of the microbiota for consistent sake quality.

Genomic characterization and probiotic potential of lactic acid bacteria isolated from feces of guinea pig (Cavia porcellus).

Presently, there exists a growing interest in mitigating the utilization of antibiotics in response to the challenges emanating from their usage in livestock. A viable alternative strategy encompasses the introduction of live microorganisms recognized as probiotics, exerting advantageous impacts on the immune system and nutritional aspects of the host animals. Native lactic acid bacteria, inherently possessing specific properties and adaptive capabilities tailored to each animal, are deemed optimal contenders for probiotic advancement. In the current investigation, microorganisms exhibiting probiotic potential were isolated, characterized, and identified from the fecal samples of guinea pigs (Cavia porcellus) belonging to the Peruvian breed. The lactic acid bacteria isolated on Man, Rogosa, and Sharpe agar underwent Gram staining, catalase testing, proteolytic, amylolytic, and cellulolytic activity assays, low pH tolerance assessment, hemolytic evaluation, antagonism against Salmonella sp., determination of autoaggregation and coaggregation capacity, and genotypic characterization through sequencing of the 16S rRNA gene. A total of 33 lactic acid bacteria were isolated from the feces of 30 guinea pigs, also 10 isolates were selected based on Gram staining and catalase testing. All strains exhibited proteolytic activity, while only one demonstrated amylolytic capability, and none displayed cellulase activity. These bacteria showed higher tolerance to pH 5.0 and, to a lesser extent, to pH 4.0. Furthermore, they exhibited antagonistic activity against Salmonella sp. Only two bacteria demonstrated hemolytic activity, and were subsequently excluded from further evaluations. Subsequent assessments revealed autoaggregation capacities ranging from 4.55% to 23.19%, with a lesser degree of coaggregation with Salmonella sp. ranging from 3.53% to 8.94% for the remaining eight bacterial isolates. Based on these comprehensive tests, five bacteria with notable probiotic potential were identified by molecular assays as Leuconostoc citreum, Enterococcus gallinarum, Exiguobacterium sp., and Lactococcus lactis. The identified bacteria stand out as promising probiotic candidates, deserving further assessment in Peruvian breed guinea pigs. This exploration aims to enhance production outcomes while mitigating the adverse effects induced by pathogenic microorganisms.