De Man Rogosa Research Articles

Antimicrobial Activity of Diffusible Substances Produced by Lactococcus lactis Against Bacillus cereus in a Non-Contact Co-Culture Model

The symptoms of foodborne illness caused by Bacillus cereus often go unreported, complicating the effectiveness of conventional chemical and physical methods used to inhibit its growth in food production. This challenge, combined with the increasing use of lactic acid bacteria (LAB) in the food industry and consumer preference for minimally processed products, prompted this study. The antibacterial activity of diffusible substances produced by Lactococcus lactis ATCC 11454 against Bacillus cereus NC11143 and Escherichia coli K-12 MG1655 was investigated using a non-contact co-culture model utilising deMann Rogosa and Sharpe broth, with glucose as a carbon source. This study employed plate counting and flow cytometry to assess the impact of these substances on bacterial growth and to analyse their composition and antimicrobial efficacy. The co-culture of Lactococcus lactis ATCC 11454 resulted in the production of a stable antimicrobial peptide, which was heat resistant and acid tolerant. Purification was achieved via ammonium sulphate precipitation and preparative HPLC, yielding a peptide with a molecular mass of 3.3 kDa, with daughter ion fractions similar to nisin A. Antimicrobial activity studies demonstrated that the diffusible substances effectively inhibited B. cereus growth over a period of eight days and exhibited bactericidal activity, killing 99% of the B. cereus cells. Additionally, these substances also inhibited Escherichia coli K-12 MG1655 grown under similar conditions. Comparative analysis revealed that in the co-culture assay, L. lactis produced a 50% higher yield of the antimicrobial peptides compared to pure cultures. Similarly, the specific growth rate of L. lactis was four times higher. With respect to protein purification and concentration, ammonium sulphate precipitation coupled with solid phase extraction was most effective in the purification and concentration of the diffusible substances. The findings provide a basis for utilising bacteriocin-producing strains as a preservation method, offering an alternative to traditional chemical and physical control approaches especially for the food industry.

ISOLATION AND MOLECULAR IDENTIFICATION OF INDIGENOUS BACTERIOCIN-PRODUCING WEISSELLA CIBARIA

Globally, over 6.22 million deaths are associated with antibiotic resistance. Bacteriocins, a set of antimicrobial peptides synthesized on the ribosomes, are widely viewed as a potential answer to this issue. This is due to their pore-forming ability and antimicrobial activity against antibiotic-resistant pathogens. The aim of this study is to isolate bacteriocin-producing Weissella cibaria and evaluate its antimicrobial activity against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Salmonella typhi, Proteus mirabilis, Streptococcus sp., Candida sp. and Rhizopus stolonifer. Weissella cibaria man1 was isolated by inoculating deMan Rogosa Sharpe (MRS) broth with small pieces of ripe Mangifera indica (mango), 24-hour incubation at 370C, 10-fold serial dilution and plating on MRS agar. Molecular identification was achieved by DNA extraction, amplification of the 16S rRNA gene through polymerase chain reaction (PCR), agarose gel electrophoresis, gene sequencing, and BLASTN homology searches in the National Center for Biotechnology Information (NCBI). Antimicrobial activity of the bacteriocin was determined by agar well diffusion assay. Mangifera indica (mango) was found to harbor bacteriocin-producing Weissella cibaria man1. The bacteriocin (weissellicin man1) exhibited a broad spectrum of antimicrobial activity. Weissellicin man1 suppressed the growth of several target pathogens (Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Proteus mirabilis, Candida sp. and Rhizopus stolonifer) but had no inhibitory action against Escherichia coli, Streptococcus sp., Staphylococcus aureus. In conclusion, weissellicin man1 from Weissella cibaria man1 has a broad-spectrum of antimicrobial action. These findings will facilitate further evaluation of the antimicrobial potency of weissellicin man1.

Respiratory Delivery of Lacticaseibacillus rhamnosus GG by Vibrating-Mesh and Jet Nebulisation

Background: The use of probiotic bacteria to improve lung health has been gaining interest. Although the oral delivery of probiotics and their effects are well documented, there is currently limited knowledge on the respiratory delivery of probiotics. Objectives: This study aimed to investigate whether nebulisation is suitable for delivering Lacticaseibacillus rhamnosus GG (LGG) into the lungs for the potential treatment of bacterial pulmonary infections. Methods: It compared the dose output and aerosol performance of a vibrating-mesh nebuliser (VMN) and a jet nebuliser (JN) in nebulising LGG suspended in de Man Rogosa Sharpe (MRS) broth, phosphate-buffered saline (PBS), or normal saline (0.9% w/v sodium chloride in water). Results: The VMN consistently produced a higher output than the JN for all liquid media, indicating that VMN was more efficient. The fine-particle fractions of both nebulisers were comparable for a given medium. The highest fine-particle fraction was achieved with LGG suspended in MRS broth for both nebulisers (20.5 ± 2.8% for VMN; 18.7 ± 3.4% for JN). This suggests that the aerosol performance of nebulised probiotics may depend on the medium in which the probiotic bacteria were suspended. Conclusions: Therefore, this study demonstrated that the nebulisation efficiency of LGG depended on the nebuliser type and liquid medium of the probiotic suspension.

Ameliorated Viability of Lactic Acid Bacteria in Fruit Juice Isolated from Indigenous Dahi with Prebiotics (Asparagus falcatus and Zingiber officinale)

Dahi is a fermented milk product containing probiotic lactic acid bacteria. This study aimed to isolate, identify, and characterize lactic acid-producing bacteria from native Dahi and evaluate their viability in orange juice using natural prebiotics. Dahi samples were obtained from local shops in Chattogram and Bogura, Bangladesh. Lactic acid-producing bacteria were isolated using MRS (de Mann Rogosa and Sharpe) medium. The isolated bacteria were identified through colony morphology, biochemical tests, and probiotic characteristics. Molecular identification was performed using polymerase chain reaction (PCR) targeting conserved 16S rDNA regions. Isolates of the genus Lactobacillus and Lactococcus lactis sp. Lactis were confirmed and used to develop probiotic orange juice. Prebiotics (Asparagus falcatus and Zingiber officinale) were added to the juice to support probiotic growth. The inoculated cell’s viability and the juice’s physicochemical parameters were evaluated during fermentation (48 hours) and storage (28 days). All fruit juice samples showed a mean number of viable cells of at least 1×105 CFU/mL during the 48-hour fermentation and 28-day storage in the refrigerator. Using natural prebiotics positively affected the survival of lactic acid bacteria, as demonstrated by bacterial colony growth on Petri dishes. Developing probiotic fruit juice enriched with prebiotics could be an effective alternative for individuals allergic or intolerant to milk-based products. Incorporating lactic acid bacteria from native Dahi into orange juice, combined with natural prebiotics, resulted in viable probiotic cells throughout fermentation and storage.

Morphology of Bacteria and Fungi From The Fermentation of Asam Drien as a Local Food Ingredient of West Aceh

A typical food ingredient of the Aceh region, especially the western and southern, is Asam drien (language from the West Aceh region). Asam drien is made from durian fruit meat, usually due to the abundance of durian fruit, or because the durian fruit is of poor quality such as the taste of the bland fruit meat, then most of the people utilize the durian fruit into Asam drien which can be used as a seasoning for cooking. The purpose of this study was to identify the morphological characteristics of bacterial and fungal colonies in Asam drien processing, this study used a qualitative descriptive method for colony characteristics, and biochemical tests. The results of research on bacteria and fungi in Asam drien found 14 colonies from the entire fermentation both at home and in the laboratory, namely irregular and diffuse, elongated, round, and threaded shapes; colony color characteristics obtained only one color, namely cream color; characteristics of colony edges there are 5, namely: wavy, squiggly, smooth, serrated, and threadbare. Colony elevation characteristics obtained 2 forms, namely flat and raised. There are 2 types of colony surface characteristics, namely rough and smooth shiny. Then reisolated on selective media DeMan Rogosa Sharpe Agar (MRS Agar) for lactic acid bacteria. The results of observations found 11 colonies from the entire fermentation each consisting of 2 types of isolates Ka and Kb which are Gram-positive bacteria bacillus and coccus cell forms. As well as fungi that grow on Asam drien, namely the genus Rhizopus and the type of yeast found from the genus Saccharomyces. The catalase test on Asam drien bacteria is positive, has proteolytic, amylolytic, and cellulolytic potential, but is not able to hydrolyze fat and alcohol.

Isolation and Identification of Swan (Cygnus olor) Digestive Tract Cellulothic Bacteria to Support Fiber Degradation

Cellulolytic bacteria are bacteria that produce cellulase enzymes capable of degrading cellulose substrates. This study aimed to isolate and identify as well as measure the cellulase enzyme activity of cellulolytic bacteria isolated from the digestive tract of swans (Cygnus olor) in Mataram. The bacteria were isolated using de Man Rogosa Sharpe (MRS) selective media with the spread plate method. Then, the extracellular enzyme activity test was conducted by growing selected pure isolates on 1% Carboxy Methyl Cellulose (CMC 1%) media, followed by pouring 0.1% congo red solution and rinsing with 1M NaCl solution to determine cellulolytic activity (cellulolytic potential indicated by the appearance of a clear zone around the colony) and measuring the cellulolytic index. The bacterial isolation results obtained 4 isolates with the potential to support fiber degradation in animal feed. The highest cellulolytic index was produced by the isolate coded S1, reaching 34.5 mm, while the lowest cellulolytic index was produced by 2 isolates coded J21 and I2, reaching 18.8 mm.

Preparation of Novel Marine Enterococcus faecium MSD8 Exopolysaccharide Ointment and In Vivo Evaluation of Its Impact on Cutaneous Wound Healing in Male Albino Rats.

The current study describes the isolation of exopolysaccharide (EPS) producing lactic acid bacteria (LAB) from marine samples and testing different sugar additives with different proportions for enhanced EPS yield. The isolate MSD8 showed the most potential, yielding 200 mg/L of EPS after being cultivated at 37 °C for48 h on de Man Rogosa and Sharpe medium (MRS) supplemented with3% sucrose. The marine isolate MSD8 was identified as Enterococcus faecium with 99.58% probability using 16S rRNA gene sequencing. The obtained sequence was deposited in GenBank and assignedthe accession number MW924065. The feature of MSD8-EPS was characterized by estimating the total carbohydrate content by UV-vis to be ~ 71%. The FTIR analysis further indicated the presence of characteristic bands of polysaccharide. The cytotoxicity of the produced MSD8-EPS was assessed using human skin fibroblasts (HSF). The IC50 was determined to be > 100 μg/mL, which signifies that MSD8-EPS is safe for skin application. The produced EPS was used to prepare a novel ointment, which was tested for wound healing ability in male albino rats. The ointment significantly (P ≤ 0.05) shortened the time needed for wound healing, as it successfully healed the wounds by 94.93% on the 7th day and completely (100%) healed the wound by the 12th day. In comparison, the control group was healed by 73.2% and 84.83%, respectively. The data confirm that the prepared ointment can safely be used for pharmaceutical wound care products.

POTENTIAL OF LACTIC ACID BACTERIA, ISOLATED FROM SEVERAL SOURCES, TO INHIBIT THE GROWTH OF Candida albicans ATCC10231

ARTICLE HIGHLIGHTS- Lactic acid bacteria have potential to control candidiasis or Candida albicans. - The novelty of this study is to advance the potential of lactic acid bacteria to control candidiasis infection in human, with a view to develop novel LAB-based probiotic candidates with capability to inhibit/prevent infection by C. albicans, the causative agent of candidiasis.ABSTRACTThe main aims of this research were to isolate and identify potential lactic acid bacteria (LAB) inhibitory to Candida albicans. The LAB sources were kimchi, honey and vaginal secrete of healthy women. They were isolated with a view to develop a novel alternative method with reduced use of antifungal agents in the treatment of patients infected by such fungal pathogen. Isolation of the LABs was conducted by applying dilution spread method on de Mann Rogosa Sharpe agar (MRSA) medium supplemented with bromo cresol purple (BCP) indicator. Once purified, they were tested for antagonism against C. albicans in dual culture assays. LAB isolates that showed significant inhibition against the pathogen were identified using 16s rDNA sequences and their sequences were aligned with those of known sequences deposited at the Gene Bank (http://www.ncbi.nlm.nih.gov). The results showed that 46 among more than 100 LABs isolated in this study significantly inhibited the growth of C. albicans in the in vitro dual culture assays, and all showed resistance property to antifungal agent (fluconazole). This indicated that they all have potential to be synergically applied with reduced use of fluconazole in the therapy. The most potential isolates (10 isolates) were closely related to three LAB species, namely Lactobacillus paracasei, Lacticaseibacillus paracasei, and Pediococcus pentosaceus, based on their 16s rDNA sequence similarities with those deposited in the GenBank.

Isolation and Molecular Characterization of Therapeutic Probiotic Lactobacillus from Different Sources in Ernakulam-Kerala

This study aims to present knowledge on therapeutic potential bacteriocin producing bacterial strains. Samples (n=35) from diverse Ernakulam sources yielded 26 lactic acid bacteria (LAB) isolates on De Man Rogosa Sharpe (MRS) medium. Among the isolates potent antimicrobial activity observed against known pathogens in one of the isolates from goat milk sample number 3, labelled as GO3. Microscopic and biochemical test revealed the isolate is Gram-positive rod, non-sporulating and resilience to pH and bile salts, with adaptability to gastric enzymes and surfactants. Genetic and physiological traits of the positive strains were confirmd by 16S rRNA technique. Blast analysis revealed that sequence of the strain GO3 from goat milk identified as Lactobacillus casei, exhibited antibiotic sensitivity, auto-aggregation, co-aggregation, and antibiofilm assays highlighted inhibitory properties as a promising therapeutic potential probiotic bacterium. LAB isolates can be further investigated at the genetic level to enhance their probiotic characteristics such as resistance and cellular adhesion. Additionally, the identification of gene responsible for expressing bacteriocins can be conducted on these isolates.

Isolation and Characterization of Beneficial Bacteria in the Guts of Cultured Sturgeon

Wild sturgeons have been harvested for their meat and caviar. Sturgeons have been cultivated to stop relying on wild stocks due to depletion. However, sturgeons take a long time to reach their sexual maturity stage. Probiotics have been said to be an ideal supplement to enhance the growth of culture sturgeon. Nevertheless, the study of beneficial bacteria in the guts of cultured sturgeon is very scarce. The purpose of this study is to isolate and characterize beneficial bacteria in the guts of culture sturgeon in Malaysia. In this study, isolation and characterization of beneficial bacteria was done in the guts of 3 different sturgeons which were Acipenser schrenckii (Amur sturgeon), Acipenser gueldenstaedtii (Russian sturgeon), and Acipenser baerii (Siberian sturgeon). The isolation of bacteria was done according to three section of guts which are foregut, midgut and hindgut and isolated on the tryptic soy agar (TSA), de Man Rogosa and Sharpe agar (MRS agar) and MRS agar with 2% of CaCO3. The total colony count and biochemical characterization including gram staining reaction, catalase and oxidase test were done on the selected colony. Total colony count revealed that hindgut area of all species is significantly higher (6.93 ± 1.39 log CFU/ml) compared to foregut (4.98 ± 2.32 log CFU/ml) and midgut (6.09 ± 0.64 log CFU/ml). Biochemical characterization results showed that all the isolates selected were gram positive, catalase negative and producing clear zones on MRS agar with 2% of CaCO3. The most potential candidate’s presence in the colony groups were genus Bacillus, Bifidobacterium and Lactobacillus. The results obtained showed that different species contain different types of bacteria. A study reported that host factors can affect the gastrointestinal microbiota of the fish. However, the weight of these three species has a big gap which were between 4.98kg to 10.51kg. Thus, the weight of the host is assumed to be another factor for the different distribution of the colonies. To conclude, further study needs to be conducted on the effect of the weight in the colonization of the beneficial bacteria in guts of culture sturgeon.

Antibacterial activity of lactic acid bacteria from black soldier fly (Hermetia illucens) larvae fed with empty fruit bunch and tofu waste

Antibiotic Growth Promoters (AGP) are prohibited for use in livestock due to their detrimental effects on consumer safety and livestock productivity. Probiotics are an alternative to AGP because they offer microorganisms that are beneficial to the livestock health. In this investigation, Lactic acid bacteria (LAB) from the Black Soldier Fly (BSF) larvae’s will be isolated, tested for their antimicrobial activities and molecularly identified using 16S rRNA gene with Polymerase Chain Reaction (PCR) technique. The larvae are fed with empty fruit bunch and tofu wastes as a source of prebiotics to the indigenous LAB. The LAB isolates were enumerated and morpho-biochemically characterized. Disk diffusion method was used to determine the antibacterial efficacy of LAB isolates against pathogenic bacteria, such as Salmonella enterica serotype Pullorum, Salmonella enterica serotype Typhimurium ATCC® 14028, and Escherichia coli ATCC® 8739. Nine bacterial isolates were purified from a population density of log 6 Colony-forming unit (CFU)/mL on de Man Rogosa Sharp (MRS) agar. Four LAB isolates were confirmed through (-) catalase activity and acids production (homofermentative). Two LAB isolates namely 5P3i3 and 5P3i5 were designated as the most potential strains against three pathogenic bacteria with the strongest inhibitory activities against E. coli, followed by S. enterica ser. Typhimurium and S. enterica ser. Pullorum. By using 16S rRNA gene sequencing, the two LAB isolates were assigned to Lactiplantibacillus pentosus and submitted to GenBank as L. pentosus strain 5P3i3 (OP445834.1) and L. pentosus strain 5P3i5 (OP445835.1). The results of this study will be further investigated with the characterization of potential isolates as probiotic candidates to be supplemented in poultry.

Identification of bacteria associated with pap (Ogi/Akamu) stored at room and refrigerated temperatures

Stored pap (ogi/akamu) has been reported to harbor several microorganisms including bacteria. The study was focused on identification of bacteria associated with pap (ogi/akamu) stored at room and refrigerated temperatures. The assayed pap was produced by soaking yellow maize (500 g) in sterile water and allowed to ferment for 72h and then grinded using home blender, sieved with a muslin cloth to obtain the pap. The pap was divided into two equal parts. One part was stored at room temperature and the other stored in a refrigerator for 9days respectively. At every 24h, each of the samples was taken to the laboratory for examination. The serially diluted pap samples were inoculated into De man rogosa and sharpe agar, nutrient agar, mannitol salt agar, salmonella shigella agar and MacConkey agar respectively and were incubated at 37 ℃ for 24h. The numbers of microbial colonies on the nutrient agar plates were counted using a colony counter. The phenotypic characterizations were carried out on the isolates and molecular identification done on the predominant lactic acid bacteria. The phenotypic characterization revealed the isolated bacteria as Lactobacillus sp., Escherichia coli, Salmonella sp. and Staphylococcus aureus. The molecular characterization confirmed the predominant bacteria as Lactobacillus plantarum FPS. The total bacterial count was more at room temperature samples (±3.78CFU/ml) than refrigerated temperature (±0.41CFU/ml). There was significant difference between the recovered bacteria at room and refrigerated temperature (p>0.05). The obtained result confirmed room temperature unsafe for storing pap and refrigerator temperature better option for storing them.

Production and profiling bioflavor compound from fermentation OPEFB hydrolysate and CPO by Lactobacillus sp.

Bioflavor is a type of natural flavor that is obtained from microbial metabolites during the process of fermentation. Most of the bacteria involved in food fermentation are lactic acid bacteria, including Lactobacillus sp. The optimal medium for Lactobacillus sp. growth is de Man Rogosa and Sharpe (MRS), but it is considered to be less economical. Therefore, alternative carbon and nitrogen sources are needed. This study aimed to determine the bioflavor produced in de Man Rogosa dan Sharpe Broth (MRSB) media that was substituted with Oil Palm Empty Fruit Bunch (OPEFB) hydrolysate and Crude Palm Oil (CPO) at concentrations of 5, 15, and 30%, respectively by using gas chromatography-mass spectrometry. The results showed that substituting MRSB with 15% CPO produced the best results for the growth of Lactobacillus sp. However, each medium produced different bioflavor compounds. In the control media (MRSB), the highest amount of bioflavor compound was 2,3-dihydro-3,5-dihydroxy-6-methyl -4H-Pyran-4-one (rose tea). In the OPEFB hydrolysate-substituted medium, it was benzene-acetaldehyde (sweet, bread, rose), in the CPO-substituted medium, it was furaneol (pineapple and strawberry) and pyrazine (nutty, roasted coffee).

Impact of Novel Functional Ingredients on Lactobacillus casei Viability

Nipple fruit (Solanum mammosum), teosinte (Dioon mejiae), Caesar mushroom (Amanita caesarea), and weevil (Rhynchophorus palmarum) powders have shown great nutritional content with meaningful dietary applications. This study aspired to investigate the impact of nipple fruit, teosinte, Caesar mushroom, and weevil powders on the bile tolerance, acid tolerance, lysozyme tolerance, gastric juice resistance, and protease activity of Lactobacillus casei. Nipple fruit, teosinte, Caesar mushroom, and weevil powders were combined at 2% (wt/vol), whereas the control samples did not include the ingredients. The bile and acid tolerances were analyzed in Difco De Man–Rogosa–Sharpe broth incubated under aerobic conditions at 37 °C. The bile tolerance was investigated by adding 0.3% oxgall, whereas the acid tolerance was studied by modifying the pH to 2.0. The lysozyme tolerance was studied in electrolyte solution containing lysozyme (100 mg/L), while the gastric juice tolerance was analyzed at pH levels of 2, 3, 4, 5, and 7. The protease activity was studied spectrophotometrically at 340 nm in skim milk incubated under aerobic conditions at 37 °C. The results show that nipple fruit increased the counts, whereas Caesar mushroom and weevil powders resulted in lower counts for bile tolerance, acid tolerance, lysozyme resistance, and simulated gastric juice tolerance characteristics. Furthermore, the protease activity increased by adding nipple fruit to skim milk. According to the results, nipple fruit may improve the characteristics of L. casei in cultured dairy by-products.

Tofu Whey-Based Media for Probiotic Lactiplantibacillus plantarum D4 as a Halal Starter Culture

In recent years, the development of probiotic-based fermented products with halal status has been a concern. The use of growth medium has relied on de Man Rogosa and Sharpe (MRS) as a relatively expensive standard medium, and its halal status is still uncertain. Extensive research has been carried out to investigate the development of low-cost halal alternative media for the cultivation of probiotic lactic acid bacteria (LAB). This study aimed to develop a probiotic halal and low-cost culture medium using a tofu whey-based medium. This study used three tofu whey-based media – A (tofu whey 100%), B (tofu whey 94.5%, molasses 3%, skim milk 2.5%), C (tofu whey 92.5%, molasses 3%, cheese whey 2.5%, tomato extract 2%), and MRS broth as a standard medium. Bacterial populations, total sugars utilized, total lactic acids produced, low pH (2.0) tolerance, and high bile salt concentration (oxgall 1.5%) were assayed. The highest bacterial population after 48 h of incubation was shown by medium B compared to medium MRS (12.34 ± 0.87 and 11.48 ± 0.3 log CFU/mL). Total sugars utilized by 48.28 ± 2.89, 38.89 ± 6.94, 39.14 ± 4.24, and 76.00 ± 1.41 %; on the other hand, total lactic acids produced by 0.16 ± 0.12, 0.03 ± 0.04, 0.31 ± 0.03, and 2.25 ± 1.48 % in A, B, C, and MRS, respectively. Probiotic tolerance at low pH and the presence of bile salts of Lactiplantibacillus plantarum D4 consistently showed a high survival rate in medium B compared to MRS. Based on these results, the components and proportions used in medium B were suitable for the growth of L. plantarum D4 as a halal probiotic starter candidate.

Isolation and Characterization of Lactic Acid Bacteria from Rice Washing Water Waste

Rice washing water is still considered as household waste because its benefits for plants are not widely known. Rice washing water is obtained from water that is washed many times before cooking which is rich in carbohydrate content in the form of starch and glucose and vitamins. Lactic acid bacteria (LAB) require sugar or carbohydrates from rice washing water which is used as food to support metabolic activity and microbial cell proliferation. LAB is also included in a large group of microorganisms that physiologically produce lactic acid as the main metabolic product. LAB are classified as good bacteria so they are widely used as food processing products, especially those related to human digestion. The use of lactic acid bacteria in the agricultural sector is still very minimal, especially as a biodecomposer, even though LAB has the ability to produce cellulase enzymes which are very important in the breakdown of lignin in organic matter. This study aims to determine the presence of lactic acid bacteria in rice washing water fermentation. Isolation of lactic acid bacteria using pour plate method with MRSA (de Man Rogosa Sharpe Agar) media. Lactic acid bacteria isolates obtained were then characterized morphologically, physically, and biochemically. The results of isolation and characterization obtained four isolates with the codes AL-01, AL-02, AL-03, and AL-04. Four LAB isolates showed gram-positive, catalase-positive, non-motile, non-H2S, and IAA-positive results.

Lactiplantibacillus plantarum postbiotic protects against Salmonella infection in broilers via modulating NLRP3 inflammasome and gut microbiota

Salmonella infection is a major concern in poultry production which poses potential risks to food safety. Our previous study confirmed that Lactiplantibacillus plantarum (LP) postbiotic exhibited a strong antibacterial capacity on Salmonella in vitro. This study aimed to investigate the beneficial effects and underlying mechanism of LP postbiotic on Salmonella-challenged broilers. A total of 240 one-day-old male yellow-feathered broilers were pretreated with 0.8% deMan Rogosa Sharpe (MRS) medium or 0.8% LP postbiotic (LP cell-free culture supernatant, LPC) in drinking water for 28 d, and then challenged with 1×109 CFU Salmonella enterica serovar Enteritidis (SE). Birds were sacrificed 3 d postinfection. Results showed that LPC maintained the growth performance by increasing body weight (BW), average daily gain (ADG), and average daily feed intake (ADFI) in broilers under SE challenge. LPC significantly attenuated SE-induced intestinal mucosal damage. Specifically, it decreased the intestinal injury score, increased villus length and villus/crypt, regulated the expression of intestinal injury-related genes (Villin, matrix metallopeptidase 3 [MMP3], intestinal fatty acid-binding protein [I-FABP]), and enhanced tight junctions (zona occludens-1 [ZO-1] and Claudin-1). SE infection caused a dramatic inflammatory response, as indicated by the up-regulated concentrations of interleukin (IL)-1β, IL-6, TNF-α, and the downregulation of IL-10, while LPC pretreatment markedly reversed this trend. We then found that LPC inhibited the activation of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome by decreasing the gene expression of Caspase-1, IL-lβ, and IL-18. Furthermore, LPC suppressed NLRP3 inflammasome activation by inhibiting nuclear factor-kappa B (NF-κB) signaling pathway (the reduced levels of toll-like receptor 4 [TLR4], myeloid differentiation factor 88 [MyD88], and NF-κB). Finally, our results showed that LPC regulated gut microbiota by enhancing the percentage of Ligilactobacillus and decreasing Alistipes and Barnesiella. In summary, we found that LP postbiotic was effective to protect broilers against Salmonella infection, possibly through suppressing NLRP3 inflammasome and optimizing gut microbiota. Our study provides the potential of postbiotics on prevention of Salmonella infection in poultry.

Efficient Screening and Enhanced Exopolysaccharide Production by Functional Lactic Acid Bacteria (LAB) in Lactose Supplemented Media

Exopolysaccharides (EPS) produced by lactic acid bacteria (LAB) can be considered as natural biological thickeners that have attracted considerable attention in the food industry. This study aimed to evaluate and select potentially EPS-producing strains LAB and to assess the influence of carbon source and aeration on EPS production. Nine LAB strains were assessed as potential EPS producers, and Rahnella aquatilis ATCC 55046 was employed as the positive control strain for EPS. The compaction test and the observation of viscous colonies in a solid medium did not yield sufficient evidence for the presence of EPS. The assessment of capsules through staining provided evidence of EPS presence only for Rahnella aquatilis ATCC 55046. The EPS yield was subsequently assessed in De-Man Rogosa and Sharpe (MRS) broth medium supplemented with 2% (w/w) fructose (MRS-f) or lactose (MRS-l), as well as in whey (Whey) and whey supplemented with 2% (w/w) lactose (Whey-l). The EPS production in the various culture media under study ranged from 194 to 1,187 mg of EPS/g of polymer dry mass (PDM). These results suggest that the culture medium and carbon sources had an impact on the EPS production of the different strains. Bifidobacterium animalisBb12 achieved the highest EPS production in MRS-f. In the case of MRS-l, the control strain recorded the highest EPS value, along with Lactobacillus acidophilus LAC-1. Regarding Whey, Lentilactobacillus Kefir NCFB 2753 exhibited the highest EPS production, while in Whey-l, Lacticaseibacillus paracasei LCS-1 emerged as the top performer in terms of EPS production. This suggests that certain strains exhibit potential for use in the production of novel fermented EPS products, whether dairy or non-dairy.

Gut Microbiome Derived Lactic Acid Bacteria (GM-d-LAB) from Dwarf Goats (Capra aegagrus hircus) Inhibit the Resident Multiple Antibiotics Resistance Bacterial pathogens

Background: The global health threat posed by antimicrobial resistance (AMR) has created an urgent need for developing alternative treatment methods. Probiotics, especially Lactic Acid Bacteria (LAB), are gaining interest in this context, as they demonstrate health-enhancing effects and potent antimicrobial activities. The intestines of goats could be a potential origin for developing new probiotics applications in animal feed and human health. Hence this study was carried out to determine the antibiotic resistance profiles of LAB and pathogens within the intestines of Nigerian dwarf goats (Capra aegagrus hircus), the antimicrobial activity of LAB against resident MDR pathogens, and subsequent identification of bioactive LAB isolated from goat faeces in Nigeria as potential probiotics in animal feed and human health.
 Method: Selective isolation of the LAB was carried out using de Mann Rogosa Sharpe (MRS) agar while enteric pathogens were isolated on MacConkey agar. Preliminary identification was carried out based on Gram reaction, and morphological, colonial, and biochemical characteristics of each isolate. Antibiotic susceptibility profiles of all isolates were determined using the Kirby-Bauer disc diffusion method. The agar overlay method was used to test the most resistant LAB isolates for antimicrobial activity against enteric pathogens. Selected LAB isolates were identified by 16SrRNA sequencing. 
 Results: The antibiotics susceptibility profile showed that a majority (77%) of LAB isolates and minimal (҇≤10%) of enteric pathogens demonstrated resistance to at least three classes of antibiotics, indicating a pattern of multi-drug resistance. Over half (62%) of these LAB isolates displayed significant antimicrobial activity against at least five of the resident-resistant pathogens, illustrating their potential role in controlling these pathogens. The sequencing results identified the most active LAB isolates, revealing a mix of strains including Pediococcus lolli (46%), Pediococcus pentosaceus (23%), Weissella confusa (8%), Enterococcus faecium (8%), Enterococcus hirae (8%), and Lactobacillus sanfranciscensis (8%).
 Conclusion: The discovery of a diverse range of LAB strains in goat intestines with significant antimicrobial activity against resident enteric pathogens is valuable. This finding suggests the potential use of these bacteria as natural alternatives to traditional antibiotics, especially in the context of growing AMR in animal husbandry.

Invitro and Invivo Analysis of Human Milk Lactic Acid Bacteria Isolates for Their Anti-hypercholesterolemia Actions.

The aim of this study was to evaluate the cholesterol lowering ability of Lactic Acid Bacteria (LAB) isolated from human breast milk under in vitro and in vivo conditions. Six LAB isolates namely Lacticaseibacillus casei 1A, Lactobacillus gasseri 5A, Enterococcus faecium 2C, Limosilactobacillus fermentum 3D, Pediococcus acidilactici 1C, and Lactiplantibacillus plantarum 7A, were examined for their bile resistance, bile salt hydrolase activity, cholesterol assimilation and viability in cholesterol rich; DeMan Rogosa and Sharpe broth, simulated gastric, small and upper intestinal conditions. During in vivo experiments, two putative LAB isolates were orally gavage to BALB/c mice, fed with normal basal and cholesterol rich (HCD) diets, daily for a period of 4 weeks. Blood serum analysis including total serum cholesterol, triglycerides, high-density and low-density lipoprotein (LDL) cholesterol levels and total fecal LAB counts of the animals were determined. The isolates in study showed bile resistance and bile salt hydrolysis activity, while significant differences (P < 0.05) were seen in their cholesterol assimilation ability. L. gasseri 5A (195.67%) and L. plantarum 7A (193.78%) displayed highest cholesterol removal percentages, respectively. Animals in HCD, fed with L. gasseri 5A and L. plantarum 7A showed decreased levels of total cholesterol and LDL, compared to the control groups. In HCD group liver weight was increased, while fecal LAB counts were decreased. No changes were observed in behavior or body weight in all experimental groups. In conclusion, L. gasseri 5A and L. plantarum 7A isolated from human breast milk demonstrates significant hypocholesterolaemic actions in vitro and in vivo and might be considered a promising candidates for preventing hypercholesterolemia in man and animals.