Lactic Acid Bacteria Strains Research Articles

Comparison of Plasmid Curing Efficiency across Five Lactic Acid Bacterial Species.

With the recent stringent criteria for antibiotic susceptibility in probiotics, the presence of antibiotic resistance genes and plasmids associated with their transfer has become a limiting factor in the approval of probiotics. The need to remove genes related to antibiotic resistance and virulence through plasmid curing for the authorization of probiotics is increasing. In this study, we investigated the curing efficiency of ethidium bromide, acridine orange, and novobiocin at different concentrations and durations in five strains of plasmid-bearing lactic acid bacteria and examined the curing characteristics in each strain. Limosibacillus reuteri and Lacticaseibacillus paracasei exhibited curing efficiencies ranging from 5% to 44% following treatment with ethidium bromide (10-50 μg/ml) for 24-72 h, while Lactobacillus gasseri showed the highest efficiency at 14% following treatment with 10 μg/ml novobiocin for 24 h. Lactiplantibacillus plantarum, which harbors two or more plasmids, demonstrated curing efficiencies ranging from 1% to 8% after an additional 72-h treatment of partially cured strains with 10 μg/ml novobiocin. Plasmid curing in strains with larger plasmids exhibited lower efficiencies and required longer durations. In strains harboring two or more plasmids, a relatively low curing efficiency with a single treatment and a high frequency of false positives, wherein recovery occurred after curing, were observed. Although certain strains exhibited altered susceptibilities to specific antibiotics after curing, these outcomes could not be attributed to the loss of antibiotic resistance genes. Furthermore, the genomic data from the cured strains revealed minimal changes throughout the genome that did not lead to gene mutations.

Effect of the Bioprotective Properties of Lactic Acid Bacteria Strains on Quality and Safety of Feta Cheese Stored under Different Conditions.

Lately, the inclusion of additional lactic acid bacteria (LAB) strains to cheeses is becoming more popular since they can affect cheese's nutritional, technological, and sensory properties, as well as increase the product's safety. This work studied the effect of Lactiplantibacillus pentosus L33 and Lactiplantibacillus plantarum L125 free cells and supernatants on feta cheese quality and Listeria monocytogenes fate. In addition, rapid and non-invasive techniques such as Fourier transform infrared (FTIR) and multispectral imaging (MSI) analysis were used to classify the cheese samples based on their sensory attributes. Slices of feta cheese were contaminated with 3 log CFU/g of L. monocytogenes, and then the cheese slices were sprayed with (i) free cells of the two strains of the lactic acid bacteria (LAB) in co-culture (F, ~5 log CFU/g), (ii) supernatant of the LAB co-culture (S) and control (C, UHT milk) or wrapped with Na-alginate edible films containing the pellet (cells, FF) or the supernatant (SF) of the LAB strains. Subsequently, samples were stored in air, in brine, or in vacuum at 4 and 10 °C. During storage, microbiological counts, pH, and water activity (aw) were monitored while sensory assessment was conducted. Also, in every sampling point, spectral data were acquired by means of FTIR and MSI techniques. Results showed that the initial microbial population of Feta was ca. 7.6 log CFU/g and consisted of LAB (>7 log CFU/g) and yeast molds in lower levels, while no Enterobacteriaceae were detected. During aerobic, brine, and vacuum storage for both temperatures, pathogen population was slightly postponed for S and F samples and reached lower levels compared to the C ones. The yeast mold population was slightly delayed in brine and vacuum packaging. For aerobic storage at 4 °C, an elongation in the shelf life of F samples by 4 days was observed compared to C and S samples. At 10 °C, the shelf life of both F and S samples was extended by 13 days compared to C samples. FTIR and MSI analyses provided reliable estimations of feta quality using the PLS-DA method, with total accuracy (%) ranging from 65.26 to 84.31 and 60.43 to 89.12, respectively. In conclusion, the application of bioprotective LAB strains can result in the extension of feta's shelf life and provide a mild antimicrobial action against L. monocytogenes and spoilage microbiota. Furthermore, the findings of this study validate the effectiveness of FTIR and MSI techniques, in tandem with data analytics, for the rapid assessment of the quality of feta samples.

Exopolysaccharides from Weissella cibaria isolated from oats: isolation, characterisation and its application in improving the texture of set‐type yogurt

SummaryIn this study, a lactic acid bacteria strain isolated from oats was used as a producer to obtain exopolysaccharide (EPS) using MRS agar plates. The findings indicated that the bacterial strain identified as Weissella cibaria (accession number: PP515290) was shown to have good probiotic activity, adapt better to alkaline than acidic conditions, and efficiently produce EPS at concentrations of up to 7.93 g L−1. SEM images showed a smooth surface and compact particle whereas FTIR confirmed the basic functional groups of polysaccharides in the sample. Meanwhile, XRD analysis demonstrated a non‐crystalline amorphous structure and thermal analysis indicated two‐phase thermal decomposition with maximum rate at 210 °C. Subsequently, EPS from W. cibaria was applied as stabiliser in set‐type yogurt (ex situ) in comparison with yogurt using mixed culture with W. cibaria (in situ) and traditional starter culture (control). The results showed that the addition of 2% EPS significantly improved syneresis (14.31%) compared to co‐culture (27.50%) and control (29.80%) as well as increased hardness of yogurt during 2‐week refrigeration.

Antimicrobial Activity of Chalcones with a Chlorine Atom and Their Glycosides.

Chalcones, secondary plant metabolites, exhibit various biological properties. The introduction of a chlorine and a glucosyl substituent to the chalcone could enhance its bioactivity and bioavailability. Such compounds can be obtained through a combination of chemical and biotechnological methods. Therefore, 4-chloro-2'-hydroxychalcone and 5'-chloro-2'-hydroxychalcone were obtained by synthesis and then glycosylated in two filamentous fungi strains cultures, i.e., Isaria fumosorosea KCH J2 and Beauveria bassiana KCH J1.5. The main site of the glycosylation of both compounds by I. fumosorosea KCH J2 was C-2' and C-3 when the second strain was utilized. The pharmacokinetics of these compounds were predicted using chemoinformatics tools. Furthermore, antimicrobial activity tests were performed. Compounds significantly inhibited the growth of the bacteria strains Escherichia coli 10536, Staphylococcus aureus DSM 799, and yeast Candida albicans DSM 1386. Nevertheless, the bacterial strain Pseudomonas aeruginosa DSM 939 exhibited significant resistance to their effects. The growth of lactic acid bacteria strain Lactococcus acidophilus KBiMZ 01 bacteria was moderately inhibited, but strains Lactococcus rhamnosus GG and Streptococcus thermophilus KBM-1 were completely inhibited. In summary, chalcones substituted with a chlorine demonstrated greater efficacy in inhibiting the microbial strains under examination compared to 2'-hydroxychalcone, while aglycones and their glycosides exhibited similar effectiveness.

Efficient metabolic pathway modification in various strains of lactic acid bacteria using CRISPR/Cas9 system for elevated synthesis of antimicrobial compounds

Lactic acid bacteria (LAB) are known to exhibit various beneficial roles in fermentation, serving as probiotics, and producing a plethora of valuable compounds including antimicrobial activity such as bacteriocin-like inhibitory substance (BLIS) that can be used as biopreservative to improve food safety and quality. However, the yield of BLIS is often limited, which poses a challenge to be commercially competitive with the current preservation practice. Therefore, the present work aimed to establish an optimised two-plasmid CRISPR/Cas9 system to redirect the carbon flux away from lactate towards compounds with antimicrobial activity by disrupting lactate dehydrogenase gene (ldh) on various strains of LAB. The lactic acid-deficient (ldhΔ) strains caused a metabolic shift resulting in increased inhibitory activity against selected foodborne pathogens up to 78 % than the wild-type (WT) strain. The most significant effect was depicted by Enterococcus faecalis-ldh∆ which displayed prominent bactericidal effects against all foodborne pathogens as compared to the WT that showed no antimicrobial activity. The present work provided a framework model for economically important LAB and other beneficial bacteria to synthesise and increase the yield of valuable food and industrial compounds. The present work reported for the first time that the metabolism of selected LAB can be manipulated by modifying ldh to attain metabolites with higher antimicrobial activity.

In Vitro evaluation of probiotic properties of lactic acid bacteria strains isolated from juçara fruit native to the Atlantic Forest

Lactic acid bacteria (LAB) are the microorganisms most commonly used as probiotics. Since probiotic benefits are strain-dependent, there is a continuous need for research into new cultures with probiotic properties. Fruits such as juçara (Euterpe edulis Martius), a palm species from the Atlantic Forest threatened with extinction, are rich niches for microorganisms, including LAB. This study investigated the probiotic properties of Lactococcus lactis J7 and Leuconostoc pseudomesenteroides JF17 strains isolated from juçara fruits native to the Atlantic Forest. Probiotic characteristics, such as tolerance to simulated gastrointestinal fluids or juices, hydrophobicity, autoaggregation, coaggregation properties, inhibition of pathogenic microorganisms, and technological properties were evaluated. The survival rate of L. lactis J7 and L. pseudomesenteroides JF17 decreased after exposure to simulated gastrointestinal conditions; however, L. lactis J7 was more resistant, maintaining viability at the end of the enteric phase of 6.07 ± 0.16 log CFU mL-1. The J7 strain also exhibited the highest values in hydrophobicity (12.55 ± 0.52%), autoaggregation (25.63 ± 0.75%), and coaggregation capacity with E. coli ATCC 25922 (21.52 ± 0.98%) and S. Enteritidis ATCC 13076 (22.68 ± 1.01%). Both J7 and JF17 strains demonstrated antimicrobial activity, confirmed by the multilayer agar plate system. Additionally, the growth of the strains was temperature-dependent, and they were able to thrive in high concentrations of sodium chloride (6%). Thus, L. lactis J7 is a promising probiotic candidate for the development of functional products. Nevertheless, further studies using animal models are necessary to explore the properties of these probiotic bacteria. Novel strains isolated from fruits should be studied to broaden the application of probiotic microorganisms in the development of foods and medicines.

Preparation, flavor component and antioxidant activity analysis of Lactiplantibacillus plantarum NCU137 fermented rice protein

Rice protein is the main component in the byproducts of rice processing such as rice dregs and rice bran. This study aims to develop lactic acid bacteria-fermented rice protein and analyze the changes of component and bioactivity. Lactiplantibacillus plantarum NCU137 was selected as the optimum fermentation strain from sixty lactic acid bacteria strains using fermentation performance and sensory score as the criteria. NCU137 was then applied to rice protein fermentation and the process parameters were optimized by single factor and orthogonal experiments. NCU137 fermentation significantly increased the acidity, antioxidant activity, and peptide content of rice protein, and eight volatile flavor compounds were identified as characteristic aroma components as determined by SPME-GC-MS. Of them, the OAV value of 1-hexanol was up to 50.94, contributing the most to the flavor of fermented rice protein. Furthermore, the antioxidant activity and mechanism of rice protein antioxidant peptide (RPAP) on H2O2-induced Caco-2 cell damage were investigated by CCK-8 method and fluorescence microscopy. RPAP showed protective effect on cell damage in a dose-dependent manner, accompanying by reduction of oxidative components such as ROS and MDA, and increasement of antioxidant components such as SOD, CAT, and GSH-PX. The protective effect might lie in the regulation of gene transcription in Nrf2/HO-1 and apoptosis Bax/Bcl pathway, as validated by RT-qPCR assay. Shortly, the rice protein fermented by NCU137 displayed significant improvement of flavor, nutritional components, and antioxidant bioactivity. The fermentation technology provides alternative strategy for processing rice protein in rice dregs and rice bran into high-valued products.

Polar-Region Soils as Novel Reservoir of Lactic Acid Bacteria from the Genus Carnobacterium.

Polar habitats offer excellent sites to isolate unique bacterial strains due to their diverse physical, geochemical, and biological factors. We hypothesize that the unique environmental conditions of polar regions select for distinct strains of lactic acid bacteria (LAB) with novel biochemical properties. In this study, we characterized ten strains of psychrotrophic LAB isolated from hitherto poorly described sources-High Arctic and maritime Antarctic soils and soil-like materials, including ornithogenic soils, cryoconites, elephant seal colonies, and postglacial moraines. We evaluated the physiological and biochemical properties of the isolates. Based on 16S rRNA and housekeeping genes, the four LAB strains were assigned to three Carnobacterium species: C. alterfunditum, C. maltaromaticum, and C. jeotgali. The remaining strains may represent three new species of the Carnobacterium genus. All isolates were neutrophilic and halophilic psychrotrophs capable of fermenting various carbohydrates, organic acids, and alcohols. The identified metabolic properties of the isolated Carnobacterium strains suggest possible syntrophic interactions with other microorganisms in polar habitats. Some showed antimicrobial activity against food pathogens such as Listeria monocytogenes and human pathogens like Staphylococcus spp. Several isolates exhibited unique metabolic traits with potential biotechnological applications that could be more effectively exploited under less stringent technological conditions compared to thermophilic LAB strains, such as lower temperatures and reduced nutrient concentrations. Analysis of extrachromosomal genetic elements revealed 13 plasmids ranging from 4.5 to 79.5 kb in five isolates, featuring unique genetic structures and high levels of previously uncharacterized genes. This work is the first comprehensive study of the biochemical properties of both known and new Carnobacterium species and enhances our understanding of bacterial communities in harsh and highly selective polar soil ecosystems.

Levilactobacillus brevis IBARAKI-TS3 Isolated From Pickles Promotes Production of Interleukin-10 via Toll-Like Receptor 2 in Human M2 Macrophages.

M2 macrophages play an important role in food allergy. Several studies have reported that lactic acid bacteria isolated from pickles exert antiallergic effects. We investigated the effects of several strains of lactic acid bacteria on the immune function of M2 macrophages. M2 macrophages differentiated from THP-1 cell line by interleukin-4 (IL-4) and IL-13 strongly expressed CD163, CD206, and HMOX1 mRNA. Levilactobacillus brevis IBARAKI-TS3 (IBARAKI-TS3) isolated from pickles was identified as a lactic acid bacterium that enhances the expressions of IL-10 and EBI3 mRNA in M2 macrophages. IBARAKI-TS3 induced the expression of genes involved in Toll-like receptor (TLR) signaling, such as IRAK, mitogen-activated protein kinases (MAPKs), and NF-κB mRNA. IBARAKI-TS3-induced IL-10 production was suppressed by anti-TLR2-neutralizing antibodies. Furthermore, the IBARAKI-TS3-induced increase in IL-10 levels was significantly reduced in TLR2-knockdown M2 macrophages compared to M2 macrophages. These results suggest that IBARAKI-TS3 promotes of IL-10 production via TLR2 in M2 macrophages.

Organic acid type in kimchi is a key factor for determining kimchi starters for kimchi fermentation control

This study was conducted to confirm the effectiveness of kimchi starters (KSs) by investigating their growth characteristics. First, we assessed the growth characteristics of five lactic acid bacteria (LAB) strains (Lactococcus lactis WiKim0124; Companilactobacillus allii WiKim39; and Leuconostoc mesenteroides WiKim0121, WiKim33, and WiKim32) and assessed the effects of different parameters, including organic acids, salinity, acidity, and temperature, on the growth of these LAB. The findings showed that organic acids, particularly acetic and lactic acids that accumulated with the progress in fermentation, were the major players determining the microbial composition of kimchi and the growth of the KSs. Leuconostoc mesenteroides grew well in the presence of acetic and lactic acids than other starts, so it is confirmed that Leuconostoc mesenteroides can dominant in kimchi. In addition, malic acid, which is derived from kimchi ingredients, is used to induce malolactic fermentation by Lactobacillus species, and the progression of malolactic fermentation can be controlled through KSs. Our results suggest that KSs promote the production of organic acids, and the profiling of organic acids, as well as the progress of malolactic fermentation, can be controlled by selecting the suitable KS. Overall, this study demonstrates that kimchi fermentation can be controlled more effectively if the characteristics of KS are understood and used appropriately.

Susceptibility of Foodborne Pathogens to Milk-Origin Lactic Acid Bacteria Supernatants: A Comprehensive Meta-Regression Study.

This systematic review and meta-analysis compile the in vitro antimicrobial efficacy of lactic acid bacteria (LAB) supernatants against three common pathogenic bacteria found in dairy products: Salmonella spp., L. monocytogenes, and Staphylococcus aureus. After screening and analysis of full papers, identified by searches in PubMed, Scopus, and Web of Science databases, thirty-nine studies were regarded as relevant, and a total of 510 observations were recorded. The effects of moderators on inhibition diameters were assessed by adjusting three pathogen-specific meta-regression models. Results showed that, in general terms, strains from the Enterococcus genus displayed the highest inhibition values against L. monocytogenes (15.90 ± 2.138 mm), whereas Lacticaseibacillus strains were more effective against S. aureus (11.89 ± 0.573 mm). The well diffusion test outperformed the spot and disk diffusion tests, and more acidic LAB supernatants resulted in higher measurements of inhibition diameters (p < 0.001). Meta-regression models incorporating LAB genus, pathogen concentration, and incubation time explained 33.8%, 52.3%, and 19.8% of the total variance in inhibition diameters for L. monocytogenes, Salmonella spp., and S. aureus, respectively. None of the three models showed evidence of publication bias. This meta-regression study demonstrated that LAB strains present in dairy products possess a variable capacity to inhibit any of the three foodborne pathogens. Overall, L. monocytogenes was found to exhibit greater susceptibility than Salmonella spp. and S. aureus; thus, the antilisterial capacity of the selected LAB strains could be exploited in developing biocontrol strategies for cheese-making.

Improving natto quality through Co-fermentation of functionally complementary Bacillus and Lactiplantibacillus species

Natto, a nutritious fermented soybean product, is known for its health benefits. Modern production methods use Bacillus subtilis as the starter culture to ensure consistent quality. However, this method overlooks the potential positive effects of other microbial species present in traditionally, naturally fermented natto. This study explored the effects of ARTP-induced mutants of B. subtilis var. natto and several strains of lactic acid bacteria (LAB) on natto quality. The results showed that these two types of bacteria have complementary roles in fermentation. B. subtilis var. natto, with enhanced extracellular protease activity, promotes the hydrolysis of soy protein and enhances the product's ACE inhibitory and fibrinolytic activities. Meanwhile, two strains of Lactiplantibacillus plantarum reduced the content of total volatile basic nitrogen (TVB-N) while increasing the content of folic acid in the final product. In addition, B. subtilis var. natto and LAB produce different profiles of volatile compounds (VOCs). Subsequently, B. subtilis var. natto and Lpb. plantarum were used to co-ferment natto in different ratios. The results showed that the two types of bacteria could co-colonize and enhance fermentation quality through their respective strengths. Specifically, Lpb. plantarum strains co-metabolized with B. subtilis var. natto to elevate the content of pyrazines, characteristic VOCs in natto. The optimal quality of natto was achieved when Lpb. plantarum HIS6, Lpb. plantarum LP3 and B. subtilis var. natto Y15-11 were combined in a 2:1:2 ratio. This study not only identified effective combinations of starter cultures with complementary benefits but also elucidated the metabolic pathways of key volatile compounds. Our findings also provide technical insights for improving natto quality, enhancing consumer acceptance, and supporting industrial production.

Exogenous inoculation of Pediococcus pentosaceus SSC12 positively regulates anthocyanin biosynthesis to alleviate browning of postharvest litchi (Litchi chinensis Sonn.)

Litchi is prone to pericarp browning after-harvest, which seriously affects the quality of litchi and causes huge loss. Pericarp browning is closely related to anthocyanin metabolism. Lactic acid bacteria (LAB), a kind of probiotics, is used for food preservation. The aim of this study was to investigate whether and how inoculation of LAB strain Pediococcus pentosaceus SSC12 of litchi fruit affect the pericarp browning and anthocyanin metabolism in postharvest through transcriptome and metabolome analyses. This is the first work showing that strain SSC12 suppressed development of browning and maintained the coloration of litchi pericarp at 10 ± 1 °C. Strain SSC12 upregulated 8 key differentially expressed genes (DEGs) associated with anthocyanin biosynthesis and transport, while downregulated 3 key DEGs involved in anthocyanin degradation in anthocyanin synthesis pathway. Strain SSC12 caused increase in 9 different anthocyanin-related metabolites levels and phenylalanine ammonia lyase activity, disease in peroxidase, laccase and polyphenol oxidase activities. Taken together, strain SSC12 suppressed browning of litchi via elevateing anthocyanin synthesis and transport and inhibiting anthocyanin degradation. These findings suggested that strain SSC12 might serve as a potential probiotic strains to alternative for chemical reagents in postharvest fruit preservation and contribute to the exploration of newgreen approachs for postharvest losses.

Characterization of probiotics isolated from dietary supplements and evaluation of metabiotic-antibiotic combinations as promising therapeutic options against antibiotic-resistant pathogens using time-kill assay

BackgroundThe global probiotics dietary supplements market size is continuously growing. To overcome probiotics’ health concerns, metabiotics are recognized as a safer alternative. Aiming to deal with the escalating antimicrobial resistance, the current work demonstrates synergistic metabiotic-antibiotic combinations against antibiotic-resistant pathogens.MethodsThe probiotic properties of lactic acid bacteria (LAB) strains isolated from 3 commercial dietary supplements were characterized in vitro. The combinations of the cell-free supernatants (CFS) of selected probiotic strains and conventional antibiotics against Staphylococcus aureus and Escherichia coli clinical isolates were evaluated using the time-kill assay. To our knowledge, the current literature lacks sufficient time-kill assay studies revealing the kinetics of such metabiotic-antibiotic combinations against S. aureus and E. coli.ResultsFour LAB strains isolated from dietary supplements as well as two reference strains were included in this study. The isolated LAB strains were identified by MALDI-TOF mass spectrometry as follows: P2: Lactobacillus acidophilus, P3: Lactiplantibacillus plantarum, P4: Lacticaseibacillus rhamnosus, and P5: Pediococcus acidilactici. The identification matched with that annotated by the manufacturers, except for P3. The tested strains could resist the acidic environment at pH 3. Excluding P2, the examined strains showed less than 1 log reduction in survivors upon the addition of reconstituted skimmed milk to pepsin at pH 2 and displayed an acceptable tolerance to 0.3% ox-bile. All the strains tolerated pancreatin. The hydrophobicity and autoaggregation capacities ranged between 7–92% and 36–66%, respectively. P2 was excluded owing to its inferior probiotic potential. Although the remaining strains showed excellent growth at 0.2% phenol, their growth was reduced at higher concentrations. L. plantarum and P. acidilactici strains possessed bile salt hydrolysis activity. The time-kill assay revealed promising synergistic activities of the combinations of CFS of L. rhamnosus P4 with either ceftazidime or gentamicin against E. coli and with only ceftazidime against S. aureus, as well as CFS of P. acidilactici P5 and ceftazidime against S. aureus.ConclusionsStrict identification and evaluation of the probiotic strains incorporated in dietary supplements is crucial to ensure their safety and efficacy. The CFS of probiotics could be utilized to formulate novel biotherapeutics targeting problematic pathogens. However, future in vivo studies are required to evaluate the appropriate treatment regimen.

Extracting and Characterizing Lactic Acid Bacteria from Human Milk

The greatest diet for babies is breast milk since it meets all of their nutritional needs and promotes healthy growth and development. Human milk contains thousands of different bacteria, the most prevalent ones being lactobacillus and Bifido bacterium. Since the use of probiotics is growing daily, it's important to comprehend their properties and health advantages. The combination of protein, fats, carbs, lipids, minerals, and vitamins found in breast milk helps to nourish an infant's body. Additionally, the bacteria in breast milk offer defense against infections. We will learn about lactic acid bacteria from this study so that we can commercially make probiotics from strains of these bacteria without utilizing lactose, as certain people are lactose intolerant and do not consume any lactose-containing products. The purpose of this article is to identify and isolate lactic acid bacteria while also discussing the advantages of probiotics for health. To understand the role lactic acid bacteria (LAB) from human milk play in the development and health of neonates, LAB must be extracted and identified. This study's objective was to identify, characterize, and segregate LAB strains from human milk samples obtained from nursing mothers in good health. The first isolation was carried out using selective medium, and then morphological, biochemical, and molecular characterization were performed. Through 16S rRNA gene sequencing, the isolates were identified. All things considered, the development of the neonatal gut microbiota and the overall health of infants depend on lactic acid bacteria (LAB). This review's objective is to gather the most recent data on the identification and isolation of LAB from human milk, with an emphasis on the techniques employed, the types of LAB discovered, and any potential health risks. Human milk is an essential source of beneficial bacteria, including several species of lactobacilli (LAB), due to its complex and dynamic nature. Our ability to isolate and accurately identify these germs has improved due to technological advancements in the molecular and microbiological sciences. This paper provides an extensive overview of the methods utilized to extract LAB from human milk, the genera and species that are commonly detected, and the implications of these findings for the nutrition and health of neonates.

Comparative microbiological, chemical, and sensory traits of aron fermentation in Tengger and laboratory scales

Aron, a traditional fermented food of the Tengger community, is made from white corn grown in Bromo and has received limited microbiological, chemical, and sensory research attention to date. The research objective was to compare microbiological, chemical, and sensory traits between in situ-produced aron on the slopes of Mount Bromo and ex situ-produced aron in a laboratory in Surabaya. A specific strain of lactic acid bacteria was isolated using de Man, Rogosa, and Sharpe (MRS) Agar from samples of sun-dried white corn. This strain was identified as Gram-positive cocci. In contrast, a different strain of Gram-positive bacilli was found in corn-soaking water, both in situ and in laboratory-fermented aron, on days 0, 7, and 16. Chemical analysis revealed no significant differences in protein, fat, and ash content between the two variables. However, laboratory-fermented aron exhibited higher moisture content. This discrepancy significantly influenced the hedonic texture data for aron, with in situ aron being perceived as drier and more mouth-soluble, while laboratory-fermented aron had a softer texture. Furthermore, the high microbial growth during the fermentation process resulted in aron with a distinct and relatively strong aroma that was less favored by the panelists. The difference in the fermentation location of white corn did not affect the types of lactic acid bacteria that thrived, the nutritional compound content, and the appearance of aron. The variation in the aroma of aron is believed to be primarily influenced by the number of bacteria rather than their specific strains.

Effects of Probiotic Supplementation on Body Weight, Growth Performance, Immune Function, Intestinal Microbiota and Metabolites in Fallow Deer.

Intestinal diseases are one of the diseases that affect the growth and immunity of deer. Currently, more lactic acid bacteria (LAB) are available as feed additives to improve the intestinal ecological balance of ruminants in production practices. In this study, Enterococcus faecalis was supplemented in the feed of fallow deer for 170 d, and body weights, blood indices and immune levels of fallow deer were counted at 35, 65 and 170 d. The effects of Enterococcus faecalis on the intestinal microbiota and the metabolism of fallow deer were analysed using 16S rDNA and UPLC-MS/MS methods. The results showed that the addition of Enterococcus faecalis to the diet improved body weight and immune function and increased the aggregation of gut microbiota in fallow deer. The addition of Enterococcus faecalis altered the community structure of intestinal microorganisms in fallow deer and increased the number of beneficial bacteria. In addition, combined with metabolomics analysis, it was found that supplementation with Enterococcus faecalis significantly altered the metabolites of fallow deer, mainly regulating lipid metabolism, carbohydrate metabolism and phospholipid metabolism. In conclusion, this study presents, for the first time, evidence that the LAB strain Enterococcus faecalis can be used as a potential probiotic for deer and points to a new direction for the treatment of intestinal disorders in the deer family.

Multi-functional properties of lactic acid bacteria strains derived from canine feces.

Probiotics, especially Lactic Acid Bacteria (LAB), can promote the health of host animals in a variety of ways, such as regulating intestinal flora and stimulating the host's immune system. In this study, 206 LAB strains were isolated from 48 canine fecal samples. Eleven LAB strains were selected based on growth performance, acid and bile salt resistance. The 11 candidates underwent comprehensive evaluation for probiotic properties, including antipathogenic activity, adhesion, safety, antioxidant capacity, and metabolites. The results of the antipathogenic activity tests showed that 11 LAB strains exhibited strong inhibitory effect and co-aggregation ability against four target pathogens (E. coli, Staphylococcus aureus, Salmonella braenderup, and Pseudomonas aeruginosa). The results of the adhesion test showed that the 11 LAB strains had high cell surface hydrophobicity, self-aggregation ability, biofilm-forming ability and adhesion ability to the Caco-2 cells. Among them, Lactobacillus acidophilus (L177) showed strong activity in various adhesion experiments. Safety tests showed that 11 LAB strains are sensitive to most antibiotics, with L102, L171, and L177 having the highest sensitivity rate at 85.71%, and no hemolysis occurred in all strains. Antioxidant test results showed that all strains showed good H2O2 tolerance, high scavenging capacity for 1, 1-diphenyl-2-trinitrophenylhydrazine (DPPH) and hydroxyl (OH-). In addition, 11 LAB strains can produce high levels of metabolites including exopolysaccharide (EPS), γ-aminobutyric acid (GABA), and bile salt hydrolase (BSH). This study provides a thorough characterization of canine-derived LAB strains, highlighting their multifunctional potential as probiotics. The diverse capabilities of the strains make them promising candidates for canine dietary supplements, offering a holistic approach to canine health. Further research should validate their efficacy in vivo to ensure their practical application.

Mixed culture fermentation using Lactobacillus delbrueckii and novel Lactiplantibacillus plantarum strains isolated from traditional chhurpi from Sikkim Himalayan region for potential probiotic and improved functional properties

The aim of the study was to isolate potential probiotic lactic acid bacteria (LAB) strains from the traditional fermented milk products, Chhurpi of the Sikkim Himalayan region and to prepare curd using mixed culture fermentation. A preliminary probiotic assessment of 110 LAB isolates including antimicrobial activity, bile and acid tolerance, surface hydrophobicity, auto-aggregation and co-aggregation, and adhesion to Caco-2 cells, was performed. Lactiplantibacillus plantarum strains N4, CHDE2, CHDE4, and SS22 demonstrated better viability in bile (0.3%) and acid (pH 2.5), adherence with hydrophobicity (13.93–92.85%), auto-aggregation (72.44–89.74%), adhesion to Caco-2 cells (45–73.61%) and antimicrobial activity against food borne pathogens. These strains were used for mixed culture fermentation with a previously screened curd forming strain Lactobacillus delbrueckii WS4. Curd produced using mixed culture fermentation of Lb. delbrueckii WS4 and the selected Lp. plantarum strains had a relatively higher acid production (pH 3.97–4.01), protein hydrolysis, and antioxidant activity. Further, mixed culture fermentation also resulted in the increase of HOCl scavenging activity (12.22–32.96%), myeloperoxidase (MPO) inhibition activity (22.38–42.94%) and angiotensin converting enzyme (ACE) inhibition (15.61–33.03%) as compared to that of WS4 fermentation (P < 0.05). This is the first report on identification of potential probiotic strains from the traditional fermented milk products of Sikkim and application in mixed culture fermentation with enhanced multifunctional potential.

Screening of the Lipid-Lowering Probiotic Lactiplantibacillus Plantarum SDJ09 and its Anti-Obesity Mechanism.

In this study, 39 strains of lactic acid bacteria were screened from several fermented foods. Based on the evaluation of functional and prebiotic properties, Lactiplantibacillus plantarum SDJ09 was selected as a promising candidate. It gave a 48.16% cholesterol reduction and 33.73% pancreatic lipase inhibition in cells; exhibited high resistance to acid, bile salts, and gastrointestinal fluid; and had strong antibacterial activity and high adhesion capabilities. More importantly, the lipid-lowering effect of L. plantarum SDJ09 was also investigated using 3T3-L1 mature adipocytes and HepG2 nonalcoholic fatty liver disease models. L. plantarum SDJ09 effectively decreased triglyceride accumulation by more than 50% in both cell models, in which the expression of PPARγ, C/EBPα, aP2, and LPL in 3T3-L1 cells was significantly downregulated by L. plantarum SDJ09. L. plantarum SDJ09 also improved lipid metabolism by downregulating the expression of HMGCR, SREBP-1c, ACC, and FAS and upregulating the expression of CYP7A1 in HepG2 nonalcoholic steatohepatitis cells. Therefore, L. plantarum SDJ09 has the potential to effectively decrease obesity and non-alcoholic fatty liver disease (NAFLD) by inhibiting lipid accumulation, providing a prospective probiotic agent for anti-obesity.