Lactobacillus acidophilus are Gram-positive bacteria distributed in diverse environments, and as a component of the normal microbiota of gastrointestinal and urogenital tract, they are relevant for ...human beings. Classified as lactic acid bacteria, due to the production of lactic acid, Lactobacillus can also produce antimicrobial peptides (AMPs), which is a compound synthesized by all forms of life aiming for protecting themselves from threats and to increase their competitivity to survive in a specific environment. AMPs are molecules capable of inhibiting the growth of microorganisms and, due to the indiscriminate use of conventional antibiotics and the emergence of multi-resistant bacteria, they have become an alternative, not only for treating multi-resistant infections, but also for the identification of probiotic products and food conservation. Considering the rampant rise of bacterial resistance to classical antimicrobials, the present study aimed to isolate and characterize AMPs from L. acidophilus extracts. Lactobacillus acid extract was pre-fractionated on disposable cartridges, followed by a high-performance liquid chromatography (HPLC). The collected fractions were evaluated in a liquid growth inhibition assay allowing to identify eight fractions with antimicrobial activity, and one of them showed antimicrobial activity against Candida albicans and, for this reason, was further characterized by mass spectrometry (MS). A peptide with a molecular mass of 1788.01 Da, showing the primary sequence NEPTHLLKAFSKAGFQ, as determined by MS, was named as Doderlin. Interestingly, antimicrobial molecules isolated from L. acidophilus have already been described previously, but few reports describe AMPs effective against C. albicans as the one reported here. We show here that this newly discovered molecule has a biological property with potential to be used in pharmaceutical and food companies, in the fight against contamination and/or for treating infections caused by microorganisms, respectively.
Doderlin is a newly discovered molecule with a biological property with potential to be applied in pharmaceutical and food companies, in the fight against contamination and/or for treating infections caused by microorganisms, respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•We evaluated AFM1 adsorption by LAB and S. cerevisiaein cheese during 30 days storage.•Lactic acid bacteria decrease 94% of AFM1in cheese at day 10.•S.cerevisiaedecrease 100% of ...AFM1in cheese at day 20.•Lactic acid bacteria and S.cerevisiaedecrease 100% of AFM1in cheese at day 10.•Heat-killed cells of LAB and S.cerevisiaemay be used to reduce AFM1 exposure by cheese.
The purpose of this study was to evaluate the ability of heat-killed cells (121 °C, 10 min) from two strains of lactic acid bacteria (LAB) (Lactobacillus rhamnosus and Lactococcus lactis) and one strain of yeast (Saccharomyces cerevisiae), alone or in combination, to reduce the levels of aflatoxin M1 (AFM1) in Frescal cheese during 30 days of storage. The experimental design was totally randomized, in a 2 × 2 × 2 factorial arrangement, corresponding to two levels of LAB (0 and L. rhamnosus at 1010 cells/kg + L. lactis at 1010 cells/kg), two levels of S. cerevisiae in milk (0 and 1010 yeast cells/kg) and two AFM1 levels (0 and 0.5 µg/kg) added to the cheese curd, totaling 8 treatments with three replicates per treatment. AFM1 levels in Frescal cheese were evaluated by using a high-performance liquid chromatography. Cheese fat and protein contents were not affected (P > 0.05) by any of the treatments, and only pH decreased (P < 0.05) in all treatments from days 2 to 30 of storage (usual shelf life of this type of cheese). AFM1 levels detected in contaminated cheeses decreased on day 2 of storage, varying from 0.09 µg/kg (cheese with addition of bacterial cells) to 0.29 µg/kg (no addition of LAB or yeast cells), this may have occurred due to loss of AFM1 in the Frescal cheese whey. The concentrations of detected AFM1 decreased (P < 0.05) in all treatments from days 2 to 10 of storage, and the maximum percentage reduction of the detectable levels (100%) was achieved after 10 and 20 days of storage in cheeses containing LAB and yeast cells, or prepared with yeast cells alone, respectively. The addition of heat-killed LAB (cells of L. rhamnosus and L. lactis) and Saccharomyces cerevisiae alone or in combination, has a potential ability for adsorbing the AFM1 in Frescal cheese during 30 days of storage.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Grana Padano (GP) is the most appreciated and marketed cheese with Protected Designation of Origin in the world. The use of raw milk, the addition of undefined cultures (defined as 'sieroinnesto ...naturale'), the peculiar manufacturing proces, and the long ripening make the cheese microbiota play a decisive role in defining the quality and the organoleptic properties of the product. The knowledge on the microbial diversity associated with GP has been the subject, in recent years, of several studies aimed at understanding its composition and characteristics in order, on the one hand, to improve its technological performances and, on the other hand, to indirectly enhance the nutritional quality of the product. This review aims to briefly illustrate the main available knowledge on the composition and properties of the GP microbiota, inferred from dozens of studies carried out by both classical microbiology techniques and metagenomic analysis. The paper will essentially, but not exclusively, be focused on the lactic acid bacteria (LAB) derived from starter (SLAB) and the non-starter bacteria, both lactic (NSLAB) and non-lactic, of milk origin.
Due to a large adaptability to different cultivation conditions and limited input compared to other cereals, sorghum is considered an emerging crop. Its antioxidant properties, high fiber content and ...low glycemic index also make it a valuable addition to a healthy diet, nevertheless, the presence of antinutritional factors and the lack of gluten, hamper its use as food ingredient. This study investigated the impact of sourdough fermentation on sorghum nutritional quality. Lactic acid bacteria dominating sorghum flour and sourdough were identified by culture-dependent analysis revealing Lactiplantibacillus plantarum as the dominant species found in the mature sourdough, whereas Weissella cibaria and Weissella paramesenteroides were the species isolated the most after the first refreshment. Among yeasts, Saccharomyces cerevisiae was the most prevalent. Lactic acid bacteria pro-technological and functional performances as starter were evaluated in sorghum type-II sourdoughs through an integrated characterization combining chromatographic and NMR spectroscopic techniques. The metabolic profile of the strains mainly grouped together W. cibaria strains and W. paramesenteroides AI7 which distinguished for the intense proteolysis but also for the presence of compounds particularly interesting from a physiological perspective (allantoin, glutathione, γ-aminobutyric acid and 2-hydroxy-3-methylbutyric acid), whose concentration increased during fermentation in a species or strain specific matter.
•Lactic acid bacteria and yeasts were isolated from sorghum flour and sourdough.•Lactiplantibacillus plantarum was dominant in the mature sourdough.•LAB pro-technological and functional performances were evaluated.•Metabolome was investigated through chromatographic and NMR techniques.•W. cibaria and W. paramesenteroides strains caused an intense proteolysis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study aimed to analyze the dynamics of biomass growth, lactic acid production, and glucose consumption for three microorganisms; Weissella cibaria IBUN 090–03684, Lactobacillus pantarum IBUN ...090–03774, and Lactobacillus pantarum IBUN 04139 by using an extended logistic model. The microorganisms were cultivated in a 1 L bioreactor with pH control by using MRS medium at 37 ∘C for 24 h at 100 rpm. Weissella cibaria IBUN 090–03684 exhibited the highest product yield (1.26 gg−1), followed by Lactobacillus plantarum IBUN 04139 (0.96 gg−1), and Lactobacillus plantarum IBUN 090–03774 (0.90 gg−1), respectively. The results indicate that Weissella cibaria IBUN 090–03684 holds significant potential for large-scale lactic acid production. Furthermore, the reported modeling strategy fits well with experimental data for the three microorganisms evaluated.
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•The logistics function is a good option for estimating kinetic parameters.•W. cibaria IBUN 090–03684 is a good option for large scale lactic acid production.•Lb. plantarum IBUN 04139 has the highest lactic acid production rate.•PLA from microbial lactic acid production can replace the plastic packaging.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Resistance to antibiotics is escalating and threatening humans and animals worldwide. Different countries have legislated or promoted the ban of antibiotics as growth promoters in livestock and ...aquaculture to reduce this phenomenon. Therefore, to improve animal growth and reproduction performance and to control multiple bacterial infections, there is a potential to use probiotics as non-antibiotic growth promoters. Lactic acid bacteria (LAB) offer various advantages as potential probiotics and can be considered as alternatives to antibiotics during food-animal production. LAB are safe microorganisms with abilities to produce different inhibitory compounds such as bacteriocins, organic acids as lactic acid, hydrogen peroxide, diacetyl, and carbon dioxide. LAB can inhibit harmful microorganisms with their arsenal, or through competitive exclusion mechanism based on competition for binding sites and nutrients. LAB endowed with specific enzymatic functions (amylase, protease…) can improve nutrients acquisition as well as animal immune system stimulation. This review aimed at underlining the benefits and inputs from LAB as potential alternatives to antibiotics in poultry, pigs, ruminants, and aquaculture production.
Use of probiotic biofilms can be an alternative approach for reducing the formation of pathogenic biofilms in food industries. The aims of this study were (i) to evaluate the probiotic properties of ...bacteriocinogenic (Lactococcus lactis VB69, L. lactis VB94, Lactobacillus sakei MBSa1, and Lactobacillus curvatus MBSa3) and non-bacteriocinogenic (L. lactis 368, Lactobacillus helveticus 354, Lactobacillus casei 40, and Weissela viridescens 113) lactic acid bacteria (LAB) isolated from Brazilian's foods and (ii) to develop protective biofilms with these strains and test them for exclusion of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium. LAB were tested for survival in acid and bile salt conditions, surface properties, biosurfactant production, β-galactosidase and gelatinase activity, antibiotic resistance and presence of virulence genes. Most strains survived exposure to pH 2 and 4% bile salts. The highest percentages of auto-aggregation were obtained after 24 h of incubation. Sixty-seven percentage auto-aggregation value was observed in W. viridescens 113 and Lactobacillus curvatus MBSa3 exhibited the highest co-aggregation (69% with Listeria monocytogenes and 74.6% with E. coli O157:H7), while the lowest co-aggregation was exhibited by W. viridescens 113 (53.4% with Listeria monocytogenes and 38% with E. coli O157:H7). Tests for hemolytic activity, bacterial cell adherence with xylene, and drop collapse confirmed the biosurfactant-producing ability of most strains. Only one strain (L. lactis 368) produced β-galactosidase. All strains were negative for virulence genes cob, ccf, cylLL, cylLs, cyllM, cylB, cylA and efaAfs and gelatinase production. The antibiotic susceptibility tests indicated that the MIC for ciprofloxacin, clindamycin, gentamicin, kanamycin, and streptomycin did not exceed the epidemiological cut-off suggested by the European Food Safety Authority. Some strains were resistant to one or more antibiotics and resistance to antibiotics was species and strain dependent. In the protective biofilm assays, strains L. lactis 368 (bac-), Lactobacillus curvatus MBSa3 (bac+), and Lactobacillus sakei MBSa1 (bac+) resulted in more than six log reductions in the pathogens counts when compared to the controls. This effect could not be attributed to bacteriocin production. These results suggest that these potential probiotic strains can be used as alternatives for control of biofilm formation by pathogenic bacteria in the food industry, without conferring a risk to the consumers.
Lactic Acid Bacteria (LAB) regulate and maintain the stability of healthy microbial flora, inhibit the adhesion of pathogenic bacteria and promote the colonization of beneficial micro‐organisms. The ...drug resistance and pathogenicity of Salmonella enteritis SE47 isolated from retail eggs were investigated. Meanwhile, Enterococcus faecalis L76 and Lactobacillus salivarius LAB35 were isolated from intestine of chicken. With SE47 as indicator bacteria, the diameters of L76 and LAB35 inhibition zones were 12 mm and 8·5 mm, respectively, by agar inhibition circle method, which indicated that both of them had inhibitory effect on Salmonella, and L76 had better antibacterial effect; two chicken‐derived lactic acid bacteria isolates and Salmonella SE47 were incubated with Caco‐2. The adhesion index of L76 was 17·5%, which was much higher than that of LAB35 (10·21%) and SE47 (4·89%), this experiment shows that the higher the bacteriostatic effect of potential probiotics, the stronger the adhesion ability; then Caco‐2 cells were incubated with different bacteria, and the survival of Caco‐2 cells was observed by flow cytometry. Compared with Salmonella SE47, the results showed that lactic acid bacteria isolates could effectively protect Caco‐2 cells; finally, after different bacteria incubated Caco‐2 cells, according to the cytokine detection kit, the RNA of Caco‐2 cells was extracted and transcribed into cDNA, then detected by fluorescence quantitative PCR, the results showed that L76 could protect Caco‐2 cells from the invasion of Salmonella SE47, with less cell membrane rupture and lower expression of MIF and TNF genes. Therefore, the lactic acid bacteria isolates can effectively inhibit the adhesion of Salmonella and protect the integrity of intestinal barrier.
Significance and Impact of the Study: We evaluated the effect of Lactobacillus from chicken on Salmonella. The results showed that both Enterococcus faecalis L76 and Lactobacillus salivarius LAB35 could effectively inhibit Salmonella SE47, and the inhibitory effect of L76 was better than LAB35. Chicken derived lactic acid bacteria can effectively protect the integrity of cell membrane from Salmonella invasion by adhering to cells. Lactobacillus can effectively antagonize the immune regulation of Salmonella in vitro. It was found that L76 had better immunomodulatory effect than LAB35.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Kimchi, a traditional Korean food made by the fermentation of vegetables, has become popular globally because of its organoleptic, beneficial, and nutritional properties. Spontaneous kimchi ...fermentation in unsterilized raw materials leads to the growth of various lactic acid bacteria (LAB), which results in variations in the taste and sensory qualities of kimchi products and difficulties in the standardized industrial production of kimchi. Raw materials, kimchi varieties, ingredients, and fermentation conditions have significant effects on the microbial communities and fermentative characteristics of kimchi during fermentation. Heterofermentative LAB belonging to the genera Leuconostoc, Lactobacillus, and Weissella are likely to be key players in kimchi fermentation and have been subjected to genomic and functional studies to gain a better understanding of the fermentation process and beneficial effects of kimchi. The use of starter cultures has been considered for the industrial production of high quality, standardized kimchi. Here, we review the composition and biochemistry of kimchi microflora communities, functional and genomic studies of kimchi LAB, and perspectives for industrial kimchi production.
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CEKLJ, DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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