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Sample records for aerobic bacteria lactic

  1. Aerobic respiration metabolism in lactic acid bacteria and uses in biotechnology.

    PubMed

    Pedersen, Martin B; Gaudu, Philippe; Lechardeur, Delphine; Petit, Marie-Agnès; Gruss, Alexandra

    2012-01-01

    The lactic acid bacteria (LAB) are essential for food fermentations and their impact on gut physiology and health is under active exploration. In addition to their well-studied fermentation metabolism, many species belonging to this heterogeneous group are genetically equipped for respiration metabolism. In LAB, respiration is activated by exogenous heme, and for some species, heme and menaquinone. Respiration metabolism increases growth yield and improves fitness. In this review, we aim to present the basics of respiration metabolism in LAB, its genetic requirements, and the dramatic physiological changes it engenders. We address the question of how LAB acquired the genetic equipment for respiration. We present at length how respiration can be used advantageously in an industrial setting, both in the context of food-related technologies and in novel potential applications.

  2. Effect of applying lactic acid bacteria and propionic acid on fermentation quality and aerobic stability of oats-common vetch mixed silage on the Tibetan plateau.

    PubMed

    Zhang, Jie; Guo, Gang; Chen, Lei; Li, Junfeng; Yuan, Xianjun; Yu, Chengqun; Shimojo, Masataka; Shao, Tao

    2015-06-01

    The objective of this study was to evaluate effects of lactic acid bacteria and propionic acid on the fermentation quality and aerobic stability of oats-common vetch mixed silage by using a small-scale fermentation system on the Tibetan plateau. (i) An inoculant (Lactobacillus plantarum) (L) or (ii) propionic acid (P) or (iii) inoculant + propionic acid (PL) were used as additives. After fermenting for 60 days, silos were opened and the aerobic stability was tested for the following 15 days. The results showed that all silages were well preserved with low pH and NH3 -N, and high lactic acid content and V-scores. L and PL silages showed higher (P < 0.05) lactic acid and crude protein content than the control silage. P silage inhibited lactic acid production. Under aerobic conditions, L silage had similar yeast counts as the control silage (> 10(5) cfu/g fresh matter (FM)); however, it numerically reduced aerobic stability for 6 h. P and PL silages showed fewer yeasts (< 10(5) cfu/g FM) (P < 0.05) and markedly improved the aerobic stability (> 360 h). The result suggested that PL is the best additive as it could not only improved fermentation quality, but also aerobic stability of oats-common vetch mixed silage on the Tibetan plateau.

  3. Effect of a preparation containing lactic fermentation bacteria on the hygienic status and aerobic stability of silages.

    PubMed

    Selwet, M

    2008-01-01

    The objective of this study was to determine the influence of biological silage additive (Bonsilage) on the hygiene quality and nutritive value of maize and grass-legume silages. The experiments were conducted on FAO 240 maize (Zea mays L.) and a mixture of italian ryegrass (Lolium multiflorum L.), 50% with alfalfa (Medicago media Pers.), 50%. Group 1 was a control and comprised silage without any additives, group 2 was ensiled with the addition of 4 cm3 kg(-1) biological silage additive. After 60 days of silage process individual silages were subjected to microbiological composition, and chemical analyses of silages were also determined. Similar analyses were repeated at day 7 following exposure to oxygen. The applied biological silage additive was found to reduce (P<0.05) numbers of Clostridium, Enterobacteriaceae, yeasts and mold fungi cells, and increase (P<0.05) the number of LAB (lactic acid bacteria) in comparison with the control in both silages. Chemical analysis of the maize silage showed that the biological additive caused an increase (P<0.05) in DM (dry matter), CP (crude protein), WSC (water soluble carbohydrates), LA (lactic acid), AA (acetic acid), ethanol, and a decrease (P<0.05) in the concentration of BA (butyric acid), N-NH3 and pH value in comparison with the control. Chemical analysis of silage samples from the grass-legume mixture showed that the additive caused an increase (P<0.05) in the content of DM, CP, WSC, LA and AA in comparison with the control. Samples of silage with the addition of an inoculant were characterized by a lower (P<0.05) content of BA, N-NH3, ethanol and pH value. The biological additive impoved the aerobic stability of silages in the aerobic phase.

  4. Aerobic Anoxygenic Phototrophic Bacteria

    PubMed Central

    Yurkov, Vladimir V.; Beatty, J. Thomas

    1998-01-01

    The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic phototrophic bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the α-1, α-3, and α-4 subclasses of the class Proteobacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic phototrophic bacteria. The closest phylogenetic relatives of aerobic phototrophic bacteria include facultatively anaerobic purple nonsulfur phototrophic bacteria. Since these two bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes. PMID:9729607

  5. Lactic Acid Bacteria in Total Mixed Ration Silage Containing Soybean Curd Residue: Their Isolation, Identification and Ability to Inhibit Aerobic Deterioration

    PubMed Central

    Li, Y.; Wang, F.; Nishino, N.

    2016-01-01

    We investigated the effects of the predominant lactic acid bacteria (LAB) on the fermentation characteristics and aerobic stability of total mixed ration (TMR) silage containing soybean curd residue (SC-TMR silage). The SC-TMR materials were ensiled in laboratory silos for 14 or 56 days. LAB predominant in SC-TMR silage were identified (Exp. 1). Lactobacillus fermentum (L. fermentum) and Streptococcus bovis (S. bovis) were found in the untreated materials, Leuconostoc pseudomesenteroides (L. pseudomesenteroides) in 14-day silage and Lactobacillus plantarum (L. plantarum) in all silages. Pediococcus acidilactici (P. acidilactici), Lactobacillus paracasei (L. paracasei), and Lactobacillus brevis (L. brevis) formed more than 90% of the isolates in 56-day silage. Italian ryegrass and whole crop maize were inoculated with P. acidilactici and L. brevis isolates and the fermentation and aerobic stability determined (Exp. 2). Inoculation with P. acidilactici and L. brevis alone or combined improved the fermentation products in ryegrass silage and markedly enhanced its aerobic stability. In maize silage, P. acidilactici and L. brevis inoculation caused no changes and suppressed deterioration when combined with increases in acetic acid content. The results indicate that P. acidilactici and L. brevis may produce a synergistic effect to inhibit SC-TMR silage deterioration. Further studies are needed to identify the inhibitory substances, which may be useful for developing potential antifungal agents. PMID:26949952

  6. Biopreservation by lactic acid bacteria.

    PubMed

    Stiles, M E

    1996-10-01

    Biopreservation refers to extended storage life and enhanced safety of foods using the natural microflora and (or) their antibacterial products. Lactic acid bacteria have a major potential for use in biopreservation because they are safe to consume and during storage they naturally dominate the microflora of many foods. In milk, brined vegetables, many cereal products and meats with added carbohydrate, the growth of lactic acid bacteria produces a new food product. In raw meats and fish that are chill stored under vacuum or in an environment with elevated carbon dioxide concentration, the lactic acid bacteria become the dominant population and preserve the meat with a "hidden' fermentation. The same applies to processed meats provided that the lactic acid bacteria survive the heat treatment or they are inoculated onto the product after heat treatment. This paper reviews the current status and potential for controlled biopreservation of foods.

  7. Adequacy of Petrifilm™ Aerobic Count plates supplemented with de Man, Rogosa & Sharpe broth and chlorophenol red for enumeration of lactic acid bacteria in salami.

    PubMed

    de Castilho, Natália Parma Augusto; Okamura, Vivian Tiemi; Camargo, Anderson Carlos; Pieri, Fábio Alessandro; Nero, Luís Augusto

    2015-12-01

    The present study aimed to assess the performance of alternative protocols to enumerate lactic acid bacteria (LAB) in salami. Fourteen cultures and two mixed starter cultures were plated using six protocols: 1) Petrifilm™ Aerobic Count (AC) with MRS broth and chlorophenol red (CR), incubated under aerobiosis or 2) under anaerobiosis, 3) MRS agar with CR, 4) MRS agar with bromocresol purple, 5) MRS agar at pH5.7, and 6) All Purpose Tween agar. Samples of salami were obtained and the LAB microbiota was enumerated by plating according protocols 1, 2, 3 and 5. Regression analysis showed a significant correlation between the tested protocols, based on culture counts (p<0.05). Similar results were observed for salami, and no significant differences of mean LAB counts between selected protocols (ANOVA, p>0.05). Colonies were confirmed as LAB, indicating proper selectivity of the protocols. The results showed the adequacy of Petrifilm™ AC supplemented with CR for the enumeration of LAB in salami.

  8. Meta-analysis of effects of inoculation with homofermentative and facultative heterofermentative lactic acid bacteria on silage fermentation, aerobic stability, and the performance of dairy cows.

    PubMed

    Oliveira, André S; Weinberg, Zwi G; Ogunade, Ibukun M; Cervantes, Andres A P; Arriola, Kathy G; Jiang, Yun; Kim, Donghyeon; Li, Xujiao; Gonçalves, Mariana C M; Vyas, Diwakar; Adesogan, Adegbola T

    2017-03-22

    Forages are usually inoculated with homofermentative and facultative heterofermentative lactic acid bacteria (LAB) to enhance lactic acid fermentation of forages, but effects of such inoculants on silage quality and the performance of dairy cows are unclear. Therefore, we conducted a meta-analysis to examine the effects of LAB inoculation on silage quality and preservation and the performance of dairy cows. A second objective was to examine the factors affecting the response to silage inoculation with LAB. The studies that met the selection criteria included 130 articles that examined the effects of LAB inoculation on silage quality and 31 articles that investigated dairy cow performance responses. The magnitude of the effect (effect size) was evaluated using raw mean differences (RMD) between inoculated and uninoculated treatments. Heterogeneity was explored by meta-regression and subgroup analysis using forage type, LAB species, LAB application rate, and silo scale (laboratory or farm-scale) as covariates for the silage quality response and forage type, LAB species, diet type [total mixed ration (TMR) or non-TMR], and the level of milk yield of the control cows as covariates for the performance responses. Inoculation with LAB (≥10(5) cfu/g as fed) markedly increased silage fermentation and dry matter recovery in temperate and tropical grasses, alfalfa, and other legumes. However, inoculation did not improve the fermentation of corn, sorghum, or sugarcane silages. Inoculation with LAB reduced clostridia and mold growth, butyric acid production, and ammonia-nitrogen in all silages, but it had no effect on aerobic stability. Silage inoculation (≥10(5) cfu/g as fed) increased milk yield and the response had low heterogeneity. However, inoculation had no effect on diet digestibility and feed efficiency. Inoculation with LAB improved the fermentation of grass and legume silages and the performance of dairy cows but did not affect the fermentation of corn, sorghum

  9. Dry matter and nutritional losses during aerobic deterioration of corn and sorghum silages as influenced by different lactic acid bacteria inocula.

    PubMed

    Tabacco, E; Righi, F; Quarantelli, A; Borreani, G

    2011-03-01

    The economic damage that results from aerobic deterioration of silage is a significant problem for farm profitability and feed quality. This paper quantifies the dry matter (DM) and nutritional losses that occur during the exposure of corn and sorghum silages to air over 14 d and assesses the possibility of enhancing the aerobic stability of silages through inoculation with lactic acid bacteria (LAB). The trial was carried out in Northern Italy on corn (50% milk line) and grain sorghum (early dough stage) silages. The crops were ensiled in 30-L jars, without a LAB inoculant (C), with a Lactobacillus plantarum inoculum (LP), and with a Lactobacillus buchneri inoculum (LB; theoretical rate of 1 × 10(6) cfu/g of fresh forage). The pre-ensiled material, the silage at silo opening, and the aerobically exposed silage were analyzed for DM content, fermentative profiles, yeast and mold count, starch, crude protein, ash, fiber components, 24-h and 48-h DM digestibility and neutral detergent fiber (NDF) degradability. The yield and nutrient analysis data of the corn and sorghum silages were used as input for Milk2006 to estimate the total digestible nutrients, net energy of lactation, and milk production per Mg of DM. The DM fermentation and respiration losses were also calculated. The inocula influenced the in vitro NDF digestibility at 24h, the net energy for lactation (NE(L)), and the predicted milk yield per megagram of DM, whereas the length of time of air exposure influenced DM digestibility at 24 and 48 h, the NE(L), and the predicted milk yield per megagram of DM in the corn silages. The inocula only influenced the milk yield per megagram of DM and the air exposure affected the DM digestibility at 24h, the NE(L), and the milk yield per megagram of DM in the sorghum silages. The milk yield, after 14 d of air exposure, decreased to 1,442, 1,418, and 1,277 kg/Mg of DM for C, LB, and LP corn silages, respectively, compared with an average value of 1,568 kg of silage at

  10. Genetics of Lactic Acid Bacteria

    NASA Astrophysics Data System (ADS)

    Zagorec, Monique; Anba-Mondoloni, Jamila; Coq, Anne-Marie Crutz-Le; Champomier-Vergès, Marie-Christine

    Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer addition of starters, often performed by back-slopping, without knowing precisely the microbial species involved. It is only since about 50 years that well defined bacterial cultures have been used as starters for the fermentation of dry sausages. Nowadays, the indigenous micro-biota of fermented meat products is well identified, and the literature is rich of reports on the identification of lactic acid bacteria (LAB) present in many traditional fermented products from various geographical origin, obtained without the addition of commercial starters (See Talon, Leroy, & Lebert, 2007, and references therein).

  11. [Teichoic acids from lactic acid bacteria].

    PubMed

    Livins'ka, O P; Harmasheva, I L; Kovalenko, N K

    2012-01-01

    The current view of the structural diversity of teichoic acids and their involvement in the biological activity of lactobacilli has been reviewed. The mechanisms of effects of probiotic lactic acid bacteria, in particular adhesive and immunostimulating functions have been described. The prospects of the use of structure data of teichoic acid in the assessment of intraspecific diversity of lactic acid bacteria have been also reflected.

  12. Comparative genomics of the lactic acid bacteria

    SciTech Connect

    Makarova, K.; Slesarev, A.; Wolf, Y.; Sorokin, A.; Mirkin, B.; Koonin, E.; Pavlov, A.; Pavlova, N.; Karamychev, V.; Polouchine, N.; Shakhova, V.; Grigoriev, I.; Lou, Y.; Rokhsar, D.; Lucas, S.; Huang, K.; Goodstein, D. M.; Hawkins, T.; Plengvidhya, V.; Welker, D.; Hughes, J.; Goh, Y.; Benson, A.; Baldwin, K.; Lee, J. -H.; Diaz-Muniz, I.; Dosti, B.; Smeianov, V; Wechter, W.; Barabote, R.; Lorca, G.; Altermann, E.; Barrangou, R.; Ganesan, B.; Xie, Y.; Rawsthorne, H.; Tamir, D.; Parker, C.; Breidt, F.; Broadbent, J.; Hutkins, R.; O'Sullivan, D.; Steele, J.; Unlu, G.; Saier, M.; Klaenhammer, T.; Richardson, P.; Kozyavkin, S.; Weimer, B.; Mills, D.

    2006-06-01

    Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.

  13. Why engineering lactic acid bacteria for biobutanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Gram-positive Lactic acid bacteria (LAB) are considered attractive biocatalysts for biomass to biofuels for several reasons. They have GRAS (Generally Recognized As Safe) status that are acceptable in food, feed, and medical applications. LAB are fermentative: selected strains are capable of f...

  14. Precision genome engineering in lactic acid bacteria.

    PubMed

    van Pijkeren, Jan Peter; Britton, Robert A

    2014-08-29

    Innovative new genome engineering technologies for manipulating chromosomes have appeared in the last decade. One of these technologies, recombination mediated genetic engineering (recombineering) allows for precision DNA engineering of chromosomes and plasmids in Escherichia coli. Single-stranded DNA recombineering (SSDR) allows for the generation of subtle mutations without the need for selection and without leaving behind any foreign DNA. In this review we discuss the application of SSDR technology in lactic acid bacteria, with an emphasis on key factors that were critical to move this technology from E. coli into Lactobacillus reuteri and Lactococcus lactis. We also provide a blueprint for how to proceed if one is attempting to establish SSDR technology in a lactic acid bacterium. The emergence of CRISPR-Cas technology in genome engineering and its potential application to enhancing SSDR in lactic acid bacteria is discussed. The ability to perform precision genome engineering in medically and industrially important lactic acid bacteria will allow for the genetic improvement of strains without compromising safety.

  15. Precision genome engineering in lactic acid bacteria

    PubMed Central

    2014-01-01

    Innovative new genome engineering technologies for manipulating chromosomes have appeared in the last decade. One of these technologies, recombination mediated genetic engineering (recombineering) allows for precision DNA engineering of chromosomes and plasmids in Escherichia coli. Single-stranded DNA recombineering (SSDR) allows for the generation of subtle mutations without the need for selection and without leaving behind any foreign DNA. In this review we discuss the application of SSDR technology in lactic acid bacteria, with an emphasis on key factors that were critical to move this technology from E. coli into Lactobacillus reuteri and Lactococcus lactis. We also provide a blueprint for how to proceed if one is attempting to establish SSDR technology in a lactic acid bacterium. The emergence of CRISPR-Cas technology in genome engineering and its potential application to enhancing SSDR in lactic acid bacteria is discussed. The ability to perform precision genome engineering in medically and industrially important lactic acid bacteria will allow for the genetic improvement of strains without compromising safety. PMID:25185700

  16. [Bacteriocins produced by lactic acid bacteria].

    PubMed

    Bilková, Andrea; Sepova, Hana Kinová; Bilka, Frantisek; Balázová, Andrea

    2011-04-01

    Lactic acid bacteria comprise several genera of gram-positive bacteria that are known for the production of structurally different antimicrobial substances. Among them, bacteriocins are nowadays in the centre of scientific interest. Bacteriocins, proteinaceous antimicrobial substances, are produced ribosomally and have usually a narrow spectrum of bacterial growth inhibition. According to their structure and the target of their activity, they are divided into four classes, although there are some suggestions for a renewed classification. The most interesting and usable class are lantibiotics. They comprise the most widely commercially used and well examined bacteriocin, nisin. The non-pathogenic character of lactic acid bacteria is advantageous for using their bacteriocins in food preservation as well as in feed supplements or in veterinary medicine.

  17. Lactic acid bacteria as probiotics.

    PubMed

    Ljungh, Asa; Wadström, Torkel

    2006-09-01

    A number of Lactobacillus species, Bifidobacterium sp, Saccharomyces boulardii, and some other microbes have been proposed as and are used as probiotic strains, i.e. live microorganisms as food supplement in order to benefit health. The health claims range from rather vague as regulation of bowel activity and increasing of well-being to more specific, such as exerting antagonistic effect on the gastroenteric pathogens Clostridium difficile, Campylobacter jejuni, Helicobacter pylori and rotavirus, neutralising food mutagens produced in colon, shifting the immune response towards a Th2 response, and thereby alleviating allergic reactions, and lowering serum cholesterol (Tannock, 2002). Unfortunately, most publications are case reports, uncontrolled studies in humans, or reports of animal or in vitro studies. Whether or not the probiotic strains employed shall be of human origin is a matter of debate but this is not a matter of concern, as long as the strains can be shown to survive the transport in the human gastrointestinal (GI) tract and to colonise the human large intestine. This includes survival in the stressful environment of the stomach - acidic pH and bile - with induction of new genes encoding a number of stress proteins. Since the availability of antioxidants decreases rostrally in the GI tract production of antioxidants by colonic bacteria provides a beneficial effect in scavenging free radicals. LAB strains commonly produce antimicrobial substance(s) with activity against the homologous strain, but LAB strains also often produce microbicidal substances with effect against gastric and intestinal pathogens and other microbes, or compete for cell surface and mucin binding sites. This could be the mechanism behind reports that some probiotic strains inhibit or decrease translocation of bacteria from the gut to the liver. A protective effect against cancer development can be ascribed to binding of mutagens by intestinal bacteria, reduction of the enzymes beta

  18. Beneficial effects of lactic acid bacteria on human beings.

    PubMed

    Masood, Muhammad Irfan; Qadir, Muhammad Imran; Shirazi, Jafir Hussain; Khan, Ikram Ullah

    2011-02-01

    Lactic acid bacteria are a diverse group of bacteria that produce lactic acid as their major fermented product. Most of them are normal flora of human being and animals and produce myriad beneficial effects for human beings include, alleviation of lactose intolerance, diarrhea, peptic ulcer, stimulation of immune system, antiallergic effects, antifungal actions, preservation of food, and prevention of colon cancer. This review highlights the potential species of Lactic acid bacteria responsible for producing these effects. It has been concluded that lactic acid bacteria are highly beneficial microorganisms for human beings and are present abundantly in dairy products so their use should be promoted for good human health.

  19. The effect of lactic acid bacteria on cocoa bean fermentation.

    PubMed

    Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

    2015-07-16

    Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of cocoa pulp by microorganisms is crucial for developing chocolate flavor precursors. Yeasts conduct an alcoholic fermentation within the bean pulp that is essential for the production of good quality beans, giving typical chocolate characters. However, the roles of bacteria such as lactic acid bacteria and acetic acid bacteria in contributing to the quality of cocoa bean and chocolate are not fully understood. Using controlled laboratory fermentations, this study investigated the contribution of lactic acid bacteria to cocoa bean fermentation. Cocoa beans were fermented under conditions where the growth of lactic acid bacteria was restricted by the use of nisin and lysozyme. The resultant microbial ecology, chemistry and chocolate quality of beans from these fermentations were compared with those of indigenous (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii, Kluyveromyces marxianus and Saccharomyces cerevisiae, the lactic acid bacteria Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in control fermentations. In fermentations with the presence of nisin and lysozyme, the same species of yeasts and acetic acid bacteria grew but the growth of lactic acid bacteria was prevented or restricted. These beans underwent characteristic alcoholic fermentation where the utilization of sugars and the production of ethanol, organic acids and volatile compounds in the bean pulp and nibs were similar for beans fermented in the presence of lactic acid bacteria. Lactic acid was produced during both fermentations but more so when lactic acid bacteria grew. Beans fermented in the presence or absence of lactic acid bacteria were fully fermented, had similar shell weights and gave acceptable chocolates with no differences

  20. Occurrence and role of lactic acid bacteria in seafood products.

    PubMed

    Françoise, Leroi

    2010-09-01

    Lactic acid bacteria (LAB) in fish flesh has long been disregarded because the high post-mortem pH, the low percentage of sugars, the high content of low molecular weight nitrogenous molecules and the low temperature of temperate waters favor the rapid growth of pH-sensitive psychrotolerant marine Gram-negative bacteria like Pseudomonas, Shewanella and Photobacterium. In seafood packed in both vacuum (VP) and modified atmosphere (MAP) packaging commonly CO(2) enriched, the growth of the Gram-negative aerobic bacteria group (predominantly pseudomonads) is effectively inhibited and the number reached by LAB during storage is higher than that achieved in air but always several log units lower than the trimethylamine oxide (TMA-O) reducing and CO(2)-resistant organisms (Shewanella putrefaciens and Photobacterium phosphoreum). Accordingly, LAB are not of much concern in seafood neither aerobically stored nor VP and MAP. However, they may acquire great relevance in lightly preserved fish products (LPFP), including those VP or MAP. Fresh fish presents a very high water activity (aw) value (0.99). However, aw is reduced to about 0.96 when salt (typically 6% WP) is added to the product. As a result, aerobic Gram-negative bacteria are inhibited, which allows the growth of other organisms more resistant to reduced aw, i.e. LAB, and then they may acquire a central role in the microbial events occurring in the product. Changes in consumers' habits have led to an increase of convenient LPFP with a relative long shelf-life (at least 3 weeks) which, on the other hand, may constitute a serious problem from a safety perspective since Listeria monocytogenes and sometimes Clostridium botulinum (mainly type E) may able to grow. In any case the LAB function in marine products is complex, depending on species, strains, interaction with other bacteria and the food matrix. They may have no particular effect or they may be responsible for spoilage and, in certain cases, they may even exert

  1. Characterization and application of lactic acid bacteria for tropical silage preparation.

    PubMed

    Pholsen, Suradej; Khota, Waroon; Pang, Huili; Higgs, David; Cai, Yimin

    2016-10-01

    Strains TH 14, TH 21 and TH 64 were isolated from tropical silages, namely corn stover, sugar cane top and rice straw, respectively, prepared in Thailand. These strains were selected by low pH growth range and high lactic acid-producing ability, similar to some commercial inoculants. Based on the analysis of 16S ribosomal RNA gene sequence and DNA-DNA relatedness, strain TH 14 was identified as Lactobacillus casei, and strains TH 21 and TH 64 were identified as L. plantarum. Strains TH 14, TH 21, TH 64 and two commercial inoculants, CH (L. plantarum) and SN (L. rhamnosus), were used as additives to fresh and wilted purple Guinea and sorghum silages prepared using a small-scale fermentation method. The number of epiphytic lactic acid bacteria (LAB) in the forages before ensilage was relatively low but the numbers of coliform and aerobic bacteria were higher. Sorghum silages at 30 days of fermentation were all well preserved with low pH (3.56) and high lactic acid production (72.86 g/kg dry matter). Purple Guinea silage inoculated with LAB exhibited reduced count levels of aerobic and coliform bacteria, lower pH, butyric acid and ammonia nitrogen and increased lactic acid concentration, compared with the control. Strain TH 14 more effectively improved lactic acid production compared with inoculants and other strains. © 2016 Japanese Society of Animal Science.

  2. Towards lactic acid bacteria-based biorefineries.

    PubMed

    Mazzoli, Roberto; Bosco, Francesca; Mizrahi, Itzhak; Bayer, Edward A; Pessione, Enrica

    2014-11-15

    Lactic acid bacteria (LAB) have long been used in industrial applications mainly as starters for food fermentation or as biocontrol agents or as probiotics. However, LAB possess several characteristics that render them among the most promising candidates for use in future biorefineries in converting plant-derived biomass-either from dedicated crops or from municipal/industrial solid wastes-into biofuels and high value-added products. Lactic acid, their main fermentation product, is an attractive building block extensively used by the chemical industry, owing to the potential for production of polylactides as biodegradable and biocompatible plastic alternative to polymers derived from petrochemicals. LA is but one of many high-value compounds which can be produced by LAB fermentation, which also include biofuels such as ethanol and butanol, biodegradable plastic polymers, exopolysaccharides, antimicrobial agents, health-promoting substances and nutraceuticals. Furthermore, several LAB strains have ascertained probiotic properties, and their biomass can be considered a high-value product. The present contribution aims to provide an extensive overview of the main industrial applications of LAB and future perspectives concerning their utilization in biorefineries. Strategies will be described in detail for developing LAB strains with broader substrate metabolic capacity for fermentation of cheaper biomass.

  3. Food phenolics and lactic acid bacteria.

    PubMed

    Rodríguez, Héctor; Curiel, José Antonio; Landete, José María; de las Rivas, Blanca; López de Felipe, Félix; Gómez-Cordovés, Carmen; Mancheño, José Miguel; Muñoz, Rosario

    2009-06-30

    Phenolic compounds are important constituents of food products of plant origin. These compounds are directly related to sensory characteristics of foods such as flavour, astringency, and colour. In addition, the presence of phenolic compounds on the diet is beneficial to health due to their chemopreventive activities against carcinogenesis and mutagenesis, mainly due to their antioxidant activities. Lactic acid bacteria (LAB) are autochthonous microbiota of raw vegetables. To get desirable properties on fermented plant-derived food products, LAB has to be adapted to the characteristics of the plant raw materials where phenolic compounds are abundant. Lactobacillus plantarum is the commercial starter most frequently used in the fermentation of food products of plant origin. However, scarce information is still available on the influence of phenolic compounds on the growth and viability of L. plantarum and other LAB species. Moreover, metabolic pathways of biosynthesis or degradation of phenolic compounds in LAB have not been completely described. Results obtained in L. plantarum showed that L. plantarum was able to degrade some food phenolic compounds giving compounds influencing food aroma as well as compounds presenting increased antioxidant activity. Recently, several L. plantarum proteins involved in the metabolism of phenolic compounds have been genetically and biochemically characterized. The aim of this review is to give a complete and updated overview of the current knowledge among LAB and food phenolics interaction, which could facilitate the possible application of selected bacteria or their enzymes in the elaboration of food products with improved characteristics.

  4. Stress responses in lactic acid bacteria.

    PubMed

    van de Guchte, Maarten; Serror, Pascale; Chervaux, Christian; Smokvina, Tamara; Ehrlich, Stanislav D; Maguin, Emmanuelle

    2002-08-01

    Lactic acid bacteria (LAB) constitute a heterogeneous group of bacteria that are traditionally used to produce fermented foods. The industrialization of food bio-transformations increased the economical importance of LAB, as they play a crucial role in the development of the organoleptique and hygienic quality of fermented products. Therefore, the reliability of starter strains in terms of quality and functional properties (important for the development of aroma and texture), but also in terms of growth performance and robustness has become essential. These strains should resist to adverse conditions encountered in industrial processes, for example during starter handling and storage (freeze-drying, freezing or spray-drying). The development of new applications such as life vaccines and probiotic foods reinforces the need for robust LAB since they may have to survive in the digestive tract, resist the intestinal flora, maybe colonize the digestive or uro-genital mucosa and express specific functions under conditions that are unfavorable to growth (for example, during stationary phase or storage). Also in nature, the ability to quickly respond to stress is essential for survival and it is now well established that LAB, like other bacteria, evolved defense mechanisms against stress that allow them to withstand harsh conditions and sudden environmental changes. While genes implicated in stress responses are numerous, in LAB the levels of characterization of their actual role and regulation differ widely between species. The functional conservation of several stress proteins (for example, HS proteins, Csp, etc) and of some of their regulators (for example, HrcA, CtsR) renders even more striking the differences that exist between LAB and the classical model micro-organisms. Among the differences observed between LAB species and B. subtilis, one of the most striking is the absence of a sigma B orthologue in L. lactis ssp. lactis as well as in at least two streptococci

  5. Lactic acid bacteria production from whey.

    PubMed

    Mondragón-Parada, María Elena; Nájera-Martínez, Minerva; Juárez-Ramírez, Cleotilde; Galíndez-Mayer, Juvencio; Ruiz-Ordaz, Nora; Cristiani-Urbina, Eliseo

    2006-09-01

    The main purpose of this work was to isolate and characterize lactic acid bacteria (LAB) strains to be used for biomass production using a whey-based medium supplemented with an ammonium salt and with very low levels of yeast extract (0.25 g/L). Five strains of LAB were isolated from naturally soured milk after enrichment in whey-based medium. One bacterial isolate, designated MNM2, exhibited a remarkable capability to utilize whey lactose and give a high biomass yield on lactose. This strain was identified as Lactobacillus casei by its 16S rDNA sequence. A kinetic study of cell growth, lactose consumption, and titratable acidity production of this bacterial strain was performed in a bioreactor. The biomass yield on lactose, the percentage of lactose consumption, and the maximum increase in cell mass obtained in the bioreactor were 0.165 g of biomass/g of lactose, 100%, and 2.0 g/L, respectively, which were 1.44, 1.11, and 2.35 times higher than those found in flask cultures. The results suggest that it is possible to produce LAB biomass from a whey-based medium supplemented with minimal amounts of yeast extract.

  6. Gut mucosal immunostimulation by lactic acid bacteria.

    PubMed

    Vitiñi, E; Alvarez, S; Medina, M; Medici, M; de Budeguer, M V; Perdigón, G

    2000-12-01

    The beneficial properties of lactic acid bacteria (LAB) on human health have been frequently demonstrated. The interaction of LAB with the lymphoid cells associated to the gut to activate the mucosal immune system and the mechanisms by which they can exert an adjuvant effect is still unclear, as well as if this property is common for all the LAB. We studied the influence of the oral administration of different geneous of LAB such as Lactobacillus casei, L. acidophilus, L. rhamnosus, L. delbrueckii subsp. bulgaricus, L. plantarum, Lactococcus lactis and Streptococcus thermophilus. We determined if the LAB assayed were able to stimulate the specific, the non-specific immune response (inflammatory response), or both. We demonstrated that all the bacteria assayed were able to increase the number of IgA producing cells associated to the lamina propria of small intestine. This effect was dose dependent. The increase in IgA+ producing cells was not always correlated with an increase in the CD4+ T cell number, indicating that some LAB assayed only induced clonal expansion of B cells triggered to produce IgA. Most of them, induced an increase in the number of cells involved in the inflammatory immune response. CD8+ T cell were diminished or not affected, with exception of L. plantarum that induced an increase at low dose. This fact would mean that LAB are unable to induce cytotoxicity mechanisms. We demonstrated the importance in the selection of LAB to be used as gut mucosal adjuvant. The different behaviours observed among them on the gut mucosal immune response, specially those that induce inflammatory immune response, show that not all the LAB can be used as oral adjuvant and that the beneficial effect of them can not generalized to genous or specie. The immunoadjuvant capacity would be a property of the strain assayed.

  7. Biology of Moderately Halophilic Aerobic Bacteria

    PubMed Central

    Ventosa, Antonio; Nieto, Joaquín J.; Oren, Aharon

    1998-01-01

    The moderately halophilic heterotrophic aerobic bacteria form a diverse group of microorganisms. The property of halophilism is widespread within the bacterial domain. Bacterial halophiles are abundant in environments such as salt lakes, saline soils, and salted food products. Most species keep their intracellular ionic concentrations at low levels while synthesizing or accumulating organic solutes to provide osmotic equilibrium of the cytoplasm with the surrounding medium. Complex mechanisms of adjustment of the intracellular environments and the properties of the cytoplasmic membrane enable rapid adaptation to changes in the salt concentration of the environment. Approaches to the study of genetic processes have recently been developed for several moderate halophiles, opening the way toward an understanding of haloadaptation at the molecular level. The new information obtained is also expected to contribute to the development of novel biotechnological uses for these organisms. PMID:9618450

  8. Importance of lactic acid bacteria in Asian fermented foods

    PubMed Central

    2011-01-01

    Lactic acid bacteria play important roles in various fermented foods in Asia. Besides being the main component in kimchi and other fermented foods, they are used to preserve edible food materials through fermentation of other raw-materials such as rice wine/beer, rice cakes, and fish by producing organic acids to control putrefactive microorganisms and pathogens. These bacteria also provide a selective environment favoring fermentative microorganisms and produce desirable flavors in various fermented foods. This paper discusses the role of lactic acid bacteria in various non-dairy fermented food products in Asia and their nutritional and physiological functions in the Asian diet. PMID:21995342

  9. Production of Value-added Products by Lactic Acid Bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactic acid bacteria (LAB) are a group of facultative anaerobic, catalase negative, nonmotile and nonsporeforming–Gram positive bacteria. Most LAB utilize high energy C sources including monomer sugars to produce energy to maintain cellular structure and function. This anaerobic fermentation proce...

  10. Functional genomics of lactic acid bacteria: from food to health

    PubMed Central

    2014-01-01

    Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria and their environmental interactions. Moreover, functional genomics approaches have been used to understand the response of lactic acid bacteria to their environment. The results have been instrumental in understanding the adaptation of lactic acid bacteria in artisanal and industrial food fermentations as well as their interactions with the human host. Collectively, this has led to a detailed analysis of genes involved in colonization, persistence, interaction and signaling towards to the human host and its health. Finally, massive parallel genome re-sequencing has provided new opportunities in applied genomics, specifically in the characterization of novel non-GMO strains that have potential to be used in the food industry. Here, we provide an overview of the state of the art of these functional genomics approaches and their impact in understanding, applying and designing lactic acid bacteria for food and health. PMID:25186768

  11. Functional genomics of lactic acid bacteria: from food to health.

    PubMed

    Douillard, François P; de Vos, Willem M

    2014-08-29

    Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria and their environmental interactions. Moreover, functional genomics approaches have been used to understand the response of lactic acid bacteria to their environment. The results have been instrumental in understanding the adaptation of lactic acid bacteria in artisanal and industrial food fermentations as well as their interactions with the human host. Collectively, this has led to a detailed analysis of genes involved in colonization, persistence, interaction and signaling towards to the human host and its health. Finally, massive parallel genome re-sequencing has provided new opportunities in applied genomics, specifically in the characterization of novel non-GMO strains that have potential to be used in the food industry. Here, we provide an overview of the state of the art of these functional genomics approaches and their impact in understanding, applying and designing lactic acid bacteria for food and health.

  12. Identification of vancomycin-resistant lactic bacteria isolated from humans.

    PubMed Central

    Mackey, T; Lejeune, V; Janssens, M; Wauters, G

    1993-01-01

    By using cell morphology, arginine dihydrolase, and gas production in de Man, Sharp, Rogosa broth, 122 isolates of vancomycin-resistant lactic bacteria from humans were assigned to five profiles, allowing us to distinguish Pediococcus, homofermentative and heterofermentative Lactobacillus, and Leuconostoc species. The absence of L-(+)-lactic acid, as detected spectrophotometrically, was confirmatory for Leuconostoc species. API 50 CHL panels were useful for the identification of Lactobacillus species. PMID:8408575

  13. Fermentation characteristics and lactic Acid bacteria succession of total mixed ration silages formulated with peach pomace.

    PubMed

    Hu, Xiaodong; Hao, Wei; Wang, Huili; Ning, Tingting; Zheng, Mingli; Xu, Chuncheng

    2015-04-01

    The objective of this study was to assess the use of peach pomace in total mixed ration (TMR) silages and clarify the differences in aerobic stability between TMR and TMR silages caused by lactic acid bacteria (LAB). The TMR were prepared using peach pomace, alfalfa hay or Leymus chinensis hay, maize meal, soybean meal, cotton meal, limestone, a vitamin-mineral supplement, and salt in a ratio of 6.0:34.0:44.4:7.0:5.0:2.5:1.0:0.1 on a dry matter (DM) basis. Fermentation quality, microbial composition, and the predominant LAB were examined during ensiling and aerobic deterioration. The results indicated that the TMR silages with peach pomace were well fermented, with low pH and high lactic acid concentrations. The aerobic stability of TMR silages were significantly higher than that of TMR. Compared with TMR silages with alfalfa hay, TMR silage with Leymus chinensis hay was much more prone to deterioration. Although the dominant LAB were not identical in TMR, the same dominant species, Lactobacillus buchneri and Pediococcus acidilactici, were found in both types of TMR silages after 56 d of ensiling, and they may play an important role in the aerobic stability of TMR silages.

  14. Fermentation Characteristics and Lactic Acid Bacteria Succession of Total Mixed Ration Silages Formulated with Peach Pomace

    PubMed Central

    Hu, Xiaodong; Hao, Wei; Wang, Huili; Ning, Tingting; Zheng, Mingli; Xu, Chuncheng

    2015-01-01

    The objective of this study was to assess the use of peach pomace in total mixed ration (TMR) silages and clarify the differences in aerobic stability between TMR and TMR silages caused by lactic acid bacteria (LAB). The TMR were prepared using peach pomace, alfalfa hay or Leymus chinensis hay, maize meal, soybean meal, cotton meal, limestone, a vitamin-mineral supplement, and salt in a ratio of 6.0:34.0:44.4:7.0:5.0:2.5:1.0:0.1 on a dry matter (DM) basis. Fermentation quality, microbial composition, and the predominant LAB were examined during ensiling and aerobic deterioration. The results indicated that the TMR silages with peach pomace were well fermented, with low pH and high lactic acid concentrations. The aerobic stability of TMR silages were significantly higher than that of TMR. Compared with TMR silages with alfalfa hay, TMR silage with Leymus chinensis hay was much more prone to deterioration. Although the dominant LAB were not identical in TMR, the same dominant species, Lactobacillus buchneri and Pediococcus acidilactici, were found in both types of TMR silages after 56 d of ensiling, and they may play an important role in the aerobic stability of TMR silages. PMID:25656205

  15. Isolation of lactic acid-forming bacteria from biogas plants.

    PubMed

    Bohn, Jelena; Yüksel-Dadak, Aytül; Dröge, Stefan; König, Helmut

    2017-02-20

    Direct molecular approaches provide hints that lactic acid bacteria play an important role in the degradation process of organic material to methanogenetic substrates in biogas plants. However, their diversity in biogas fermenter samples has not been analyzed in detail yet. For that reason, five different biogas fermenters, which were fed mainly with maize silage and manure from cattle or pigs, were examined for the occurrence of lactic acid-forming bacteria. A total of 197 lactic acid-forming bacterial strains were isolated, which we assigned to 21 species, belonging to the genera Bacillus, Clostridium, Lactobacillus, Pediococcus, Streptococcus and Pseudoramibacter-related. A qualitative multiplex system and a real-time quantitative PCR could be developed for most isolates, realized by the selection of specific primers. Their role in biogas plants was discussed on the basis of the quantitative results and on physiological data of the isolates.

  16. Effects of lactic acid bacteria contamination on lignocellulosic ethanol fermentation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Slower fermentation rates, mixed sugar compositions, and lower sugar concentrations may make lignocellulosic fermentations more susceptible to contamination by lactic acid bacteria (LAB), which is a common and costly problem to the corn-based fuel ethanol industry. To examine the effects of LAB con...

  17. Systems solutions by lactic acid bacteria: from paradigms to practice

    PubMed Central

    2011-01-01

    Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which serve as scientific paradigms. Moreover, functional and comparative metagenomic studies are taking off and provide a wealth of insight in the activity of lactic acid bacteria used in a variety of applications, ranging from starters in complex fermentations to their marketing as probiotics. In this new era of high throughput analysis, biology has become big science. Hence, there is a need to systematically store the generated information, apply this in an intelligent way, and provide modalities for constructing self-learning systems that can be used for future improvements. This review addresses these systems solutions with a state of the art overview of the present paradigms that relate to the use of lactic acid bacteria in industrial applications. Moreover, an outlook is presented of the future developments that include the transition into practice as well as the use of lactic acid bacteria in synthetic biology and other next generation applications. PMID:21995776

  18. Selection of tropical lactic acid bacteria for enhancing the quality of maize silage.

    PubMed

    Santos, A O; Ávila, C L S; Schwan, R F

    2013-01-01

    The objective of this study was to select lactic acid bacteria (LAB) strains isolated from silage and assess their effect on the quality of maize silage. The LAB strains were inoculated into aqueous extract obtained from maize to evaluate their production of metabolites and pH reduction. The ability to inhibit the pathogenic and silage-spoilage microorganisms' growth was evaluated. Nine LAB strains that showed the best results were assessed in polyvinyl chloride experimental silos. The inoculation of the LAB strains influenced the concentration of lactic and acetic acids and the diversity of Listeria. The inoculation of silages with Lactobacillus buchneri (UFLA SLM11 and UFLA SLM103 strains) resulted in silages with greater LAB populations and improvements after aerobic exposure. The UFLA SLM11 and SLM103 strains identified as L. buchneri showed to be promising in the treatment of maize silage.

  19. The aerobic activity of metronidazole against anaerobic bacteria.

    PubMed

    Dione, Niokhor; Khelaifia, Saber; Lagier, Jean-Christophe; Raoult, Didier

    2015-05-01

    Recently, the aerobic growth of strictly anaerobic bacteria was demonstrated using antioxidants. Metronidazole is frequently used to treat infections caused by anaerobic bacteria; however, to date its antibacterial activity was only tested in anaerobic conditions. Here we aerobically tested using antioxidants the in vitro activities of metronidazole, gentamicin, doxycycline and imipenem against 10 common anaerobic and aerobic bacteria. In vitro susceptibility testing was performed by the disk diffusion method, and minimum inhibitory concentrations (MICs) were determined by Etest. Aerobic culture of the bacteria was performed at 37°C using Schaedler agar medium supplemented with 1mg/mL ascorbic acid and 0.1mg/mL glutathione; the pH was adjusted to 7.2 by 10M KOH. Growth of anaerobic bacteria cultured aerobically using antioxidants was inhibited by metronidazole after 72h of incubation at 37°C, with a mean inhibition diameter of 37.76mm and an MIC of 1μg/mL; however, strains remained non-sensitive to gentamicin. No growth inhibition of aerobic bacteria was observed after 24h of incubation at 37°C with metronidazole; however, inhibition was observed with doxycycline and imipenem used as controls. These results indicate that bacterial sensitivity to metronidazole is not related to the oxygen tension but is a result of the sensitivity of the micro-organism. In future, both culture and antibiotic susceptibility testing of strictly anaerobic bacteria will be performed in an aerobic atmosphere using antioxidants in clinical microbiology laboratories.

  20. The effect of bacteria, enzymes and inulin on fermentation and aerobic stability of corn silage

    PubMed Central

    Peymanfar, S; Kermanshahi, RK

    2012-01-01

    Background and Objectives Ensiling is a conservation method for forage crops. It is based on the fact that anaerobe lactic acid bacteria (LAB) convert watersoluble carbohydrates into organic acids. Therefore, pH decreases and the forage is preserved. The aim of this study was to isolate special kinds of lactic acid bacteria from silage and to study the effect of bacteria, inulin and enzymes as silage additives on the fermentation and aerobic stability of the silage. Materials and Methods The heterofermentative LAB were isolated from corn silages in Broujerd, Iran and biochemically characterized. Acid tolerance was studied by exposure to acidic PBS and growth in bile salt was measured by the spectrophotometric method. Results The results of molecular analysis using 16SrDNA sequences showed that the isolates belonged to Lactobacillus and Enterococcus genera. To enhance stability in acidic environment and against bile salts, microencapsulation with Alginate and Chitosan was used. The Lactobacillus plantarum strains were used as control. The inoculants (1 × 107 cfu/g) alone or in combination with inulin or in combination with enzymes were added to chopped forages and ensiled in 1.5-L anaerobic jars. Conclusion Combination of the isolates Lactobacillus and Enterococcus with inulin and enzymes can improve the aerobic stability of corn silage. PMID:23205249

  1. Lactic acid bacteria as a cell factory for riboflavin production

    PubMed Central

    Thakur, Kiran; De, Sachinandan

    2015-01-01

    Summary Consumers are increasingly becoming aware of their health and nutritional requirements, and in this context, vitamins produced in situ by microbes may suit their needs and expectations. B groups vitamins are essential components of cellular metabolism and among them riboflavin is one of the vital vitamins required by bacteria, plants, animals and humans. Here, we focus on the importance of microbial production of riboflavin over chemical synthesis. In addition, genetic abilities for riboflavin biosynthesis by lactic acid bacteria are discussed. Genetically modified strains by employing genetic engineering and chemical analogues have been developed to enhance riboflavin production. The present review attempts to collect the currently available information on riboflavin production by microbes in general, while placing greater emphasis on food grade lactic acid bacteria and human gut commensals. For designing riboflavin‐enriched functional foods, proper selection and exploitation of riboflavin‐producing lactic acid bacteria is essential. Moreover, eliminating the in situ vitamin fortification step will decrease the cost of food production. PMID:26686515

  2. Degradation of organic acids by dairy lactic acid bacteria.

    PubMed

    Hegazi, F Z; Abo-Elnaga, I G

    1980-01-01

    One hundred and twelve different strains of lactic acid bacteria, belonging to the genera Leuconostoc, Streptococcus, and Lactobacillus, were examined for the ability to degrade 10 organic acids by detecting gas production, using the conventional Durham tube method. All the strains did not break down succinate, glutarate, 2-oxo-glutarate, and mucate. Malate, citrate, pyruvate, fumarate, tartrate, and gluconate were variably attacked. Streptococcus cremoiris AM2, ML8, and SK11 required glucose to produce gas from citrate, whereas Leuconostoc citrovorum and Streptococcus faecalis did not. Streptococcus cremoris differed from the other streptococci in not producing gas from gluconate. From all lactic acid bacteria examined, only Lactobacillus plantarum formed gas from tartarate. Determination of acetoin and diacetyl proved to be a more reliable evidence for assessing the degradation of pyruvate, compared with detection of gas production. Homofermentative lactobacilli and Leuconostoc citrovorum produced acetoin and diacetyl from pyruvate, whereas beta-bacteria did not, a character that would be of taxonomic value. Streptobacteria degraded pyruvate in the presence of glucose with lactate as the major product together with a mean acetate of 4.1%, ethanol 7.9%, acetoin 1.7%, and diacetyl 2.6% yield on a molar basis after 60 days at 30 degrees C. L. brevis produced acetate and lactate. Formation of diacetyl from pyruvate by lactic acid bacteria may play an important role in flavour development in fermenting dairy products, especially in cheese, where lactic acid bacteria usually predominate, and pyruvate is probably excreted in the breaking down of lactose and in the oxidative deamination of alanine by the accompanying microflora.

  3. Bacteriocins of lactic acid bacteria: extending the family.

    PubMed

    Alvarez-Sieiro, Patricia; Montalbán-López, Manuel; Mu, Dongdong; Kuipers, Oscar P

    2016-04-01

    Lactic acid bacteria (LAB) constitute a heterogeneous group of microorganisms that produce lactic acid as the major product during the fermentation process. LAB are Gram-positive bacteria with great biotechnological potential in the food industry. They can produce bacteriocins, which are proteinaceous antimicrobial molecules with a diverse genetic origin, posttranslationally modified or not, that can help the producer organism to outcompete other bacterial species. In this review, we focus on the various types of bacteriocins that can be found in LAB and the organization and regulation of the gene clusters responsible for their production and biosynthesis, and consider the food applications of the prototype bacteriocins from LAB. Furthermore, we propose a revised classification of bacteriocins that can accommodate the increasing number of classes reported over the last years.

  4. [Regulating acid stress resistance of lactic acid bacteria--a review].

    PubMed

    Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2014-07-04

    As cell factories, lactic acid bacteria are widely used in food, agriculture, pharmaceutical and other industries. Acid stress is one the important survival challenges encountered by lactic acid bacteria both in fermentation process and in the gastrointestinal tract. Recently, the development of systems biology and metabolic engineering brings unprecedented opportunity for further elucidating the acid tolerance mechanisms and improving the acid stress resistance of lactic acid bacteria. This review addresses physiological mechanisms of lactic acid bacteria during acid stress. Moreover, strategies to improve the acid stress resistance of lactic acid were proposed.

  5. In vaginal fluid, bacteria associated with bacterial vaginosis can be suppressed with lactic acid but not hydrogen peroxide

    PubMed Central

    2011-01-01

    Background Hydrogen peroxide (H2O2) produced by vaginal lactobacilli is generally believed to protect against bacteria associated with bacterial vaginosis (BV), and strains of lactobacilli that can produce H2O2 are being developed as vaginal probiotics. However, evidence that led to this belief was based in part on non-physiological conditions, antioxidant-free aerobic conditions selected to maximize both production and microbicidal activity of H2O2. Here we used conditions more like those in vivo to compare the effects of physiologically plausible concentrations of H2O2 and lactic acid on a broad range of BV-associated bacteria and vaginal lactobacilli. Methods Anaerobic cultures of seventeen species of BV-associated bacteria and four species of vaginal lactobacilli were exposed to H2O2, lactic acid, or acetic acid at pH 7.0 and pH 4.5. After two hours, the remaining viable bacteria were enumerated by growth on agar media plates. The effect of vaginal fluid (VF) on the microbicidal activities of H2O2 and lactic acid was also measured. Results Physiological concentrations of H2O2 (< 100 μM) failed to inactivate any of the BV-associated bacteria tested, even in the presence of human myeloperoxidase (MPO) that increases the microbicidal activity of H2O2. At 10 mM, H2O2 inactivated all four species of vaginal lactobacilli but only one of seventeen species of BV-associated bacteria. Moreover, the addition of just 1% vaginal fluid (VF) blocked the microbicidal activity of 1 M H2O2. In contrast, lactic acid at physiological concentrations (55-111 mM) and pH (4.5) inactivated all the BV-associated bacteria tested, and had no detectable effect on the vaginal lactobacilli. Also, the addition of 10% VF did not block the microbicidal activity of lactic acid. Conclusions Under optimal, anaerobic growth conditions, physiological concentrations of lactic acid inactivated BV-associated bacteria without affecting vaginal lactobacilli, whereas physiological concentrations of H2O2

  6. Citric acid metabolism in hetero- and homofermentative lactic acid bacteria.

    PubMed Central

    Drinan, D F; Robin, S; Cogan, T M

    1976-01-01

    The effect of citrate on production of diacetyl and acetoin by four strains each of heterofermentative and homofermentative lactic acid bacteria capable of utilizing citrate was studied. Acetoin was quantitatively the more important compound. The heterofermentative bacteria produced no acetoin or diacetyl in the absence of citrate, and two strains produced traces of acetoin in its presence. Citrate stimulated the growth rate of the heterofermentative lactobacilli. Acidification of all heterofermentative cultures with citric acid resulted in acetoin production. Destruction of accumulated acetoin appeared to coincide with the disappearance of citrate. All homofermentative bacteria produced more acetoin and diacetyl in the presence of citrate than in its absence. Citrate utilization was begun immediately by the streptococci but was delayed until at least the middle of the exponential phase in the case of the lactobacilli. PMID:5054

  7. Potential of lactic acid bacteria in aflatoxin risk mitigation.

    PubMed

    Ahlberg, Sara H; Joutsjoki, Vesa; Korhonen, Hannu J

    2015-08-17

    Aflatoxins (AF) are ubiquitous mycotoxins contaminating food and feed. Consumption of contaminated food and feed can cause a severe health risk to humans and animals. A novel biological method could reduce the health risks of aflatoxins through inhibiting mold growth and binding aflatoxins. Lactic acid bacteria (LAB) are commonly used in fermented food production. LAB are known to inhibit mold growth and, to some extent, to bind aflatoxins in different matrices. Reduced mold growth and aflatoxin production may be caused by competition for nutrients between bacterial cells and fungi. Most likely, binding of aflatoxins depends on environmental conditions and is strain-specific. Killed bacteria cells possess consistently better binding abilities for aflatoxin B1 (AFB1) than viable cells. Lactobacilli especially are relatively well studied and provide noticeable possibilities in binding of aflatoxin B1 and M1 in food. It seems that binding is reversible and that bound aflatoxins are released later on (Haskard et al., 2001; Peltonen et al., 2001). This literature review suggests that novel biological methods, such as lactic acid bacteria, show potential in mitigating toxic effects of aflatoxins in food and feed.

  8. Flow Cytometric Assessment of Viability of Lactic Acid Bacteria

    PubMed Central

    Bunthof, Christine J.; Bloemen, Karen; Breeuwer, Pieter; Rombouts, Frank M.; Abee, Tjakko

    2001-01-01

    The viability of lactic acid bacteria is crucial for their applications as dairy starters and as probiotics. We investigated the usefulness of flow cytometry (FCM) for viability assessment of lactic acid bacteria. The esterase substrate carboxyfluorescein diacetate (cFDA) and the dye exclusion DNA binding probes propidium iodide (PI) and TOTO-1 were tested for live/dead discrimination using a Lactococcus, a Streptococcus, three Lactobacillus, two Leuconostoc, an Enterococcus, and a Pediococcus species. Plate count experiments were performed to validate the results of the FCM assays. The results showed that cFDA was an accurate stain for live cells; in exponential-phase cultures almost all cells were labeled, while 70°C heat-killed cultures were left unstained. PI did not give clear live/dead discrimination for some of the species. TOTO-1, on the other hand, gave clear discrimination between live and dead cells. The combination of cFDA and TOTO-1 gave the best results. Well-separated subpopulations of live and dead cells could be detected with FCM. Cell sorting of the subpopulations and subsequent plating on agar medium provided direct evidence that cFDA labels the culturable subpopulation and that TOTO-1 labels the nonculturable subpopulation. Applied to cultures exposed to deconjugated bile salts or to acid, cFDA and TOTO-1 proved to be accurate indicators of culturability. Our experiments with lactic acid bacteria demonstrated that the combination of cFDA and TOTO-1 makes an excellent live/dead assay with versatile applications. PMID:11319119

  9. Development of Mucosal Vaccines Based on Lactic Acid Bacteria

    NASA Astrophysics Data System (ADS)

    Bermúdez-Humarán, Luis G.; Innocentin, Silvia; Lefèvre, Francois; Chatel, Jean-Marc; Langella, Philippe

    Today, sufficient data are available to support the use of lactic acid bacteria (LAB), notably lactococci and lactobacilli, as delivery vehicles for the development of new mucosal vaccines. These non-pathogenic Gram-positive bacteria have been safely consumed by humans for centuries in fermented foods. They thus constitute an attractive alternative to the attenuated pathogens (most popular live vectors actually studied) which could recover their pathogenic potential and are thus not totally safe for use in humans. This chapter reviews the current research and advances in the use of LAB as live delivery vectors of proteins of interest for the development of new safe mucosal vaccines. The use of LAB as DNA vaccine vehicles to deliver DNA directly to antigen-presenting cells of the immune system is also discussed.

  10. Current taxonomy of phages infecting lactic acid bacteria

    PubMed Central

    Mahony, Jennifer; van Sinderen, Douwe

    2013-01-01

    Phages infecting lactic acid bacteria have been the focus of significant research attention over the past three decades. Through the isolation and characterization of hundreds of phage isolates, it has been possible to classify phages of the dairy starter and adjunct bacteria Lactococus lactis, Streptococcus thermophilus, Leuconostoc spp., and Lactobacillus spp. Among these, phages of L. lactis have been most thoroughly scrutinized and serve as an excellent model system to address issues that arise when attempting taxonomic classification of phages infecting other LAB species. Here, we present an overview of the current taxonomy of phages infecting LAB genera of industrial significance, the methods employed in these taxonomic efforts and how these may be employed for the taxonomy of phages of currently underrepresented and emerging phage species. PMID:24478767

  11. Screening and characterization of novel bacteriocins from lactic acid bacteria.

    PubMed

    Zendo, Takeshi

    2013-01-01

    Bacteriocins produced by lactic acid bacteria (LAB) are expected to be safe antimicrobial agents. While the best studied LAB bacteriocin, nisin A, is widely utilized as a food preservative, various novel ones are required to control undesirable bacteria more effectively. To discover novel bacteriocins at the early step of the screening process, we developed a rapid screening system that evaluates bacteriocins produced by newly isolated LAB based on their antibacterial spectra and molecular masses. By means of this system, various novel bacteriocins were identified, including a nisin variant, nisin Q, a two-peptide bacteriocin, lactococcin Q, a leaderless bacteriocin, lacticin Q, and a circular bacteriocin, lactocyclicin Q. Moreover, some LAB isolates were found to produce multiple bacteriocins. They were characterized as to their structures, mechanisms of action, and biosynthetic mechanisms. Novel LAB bacteriocins and their biosynthetic mechanisms are expected for applications such as food preservation and peptide engineering.

  12. Naturally Occurring Lactic Acid Bacteria Isolated from Tomato Pomace Silage

    PubMed Central

    Wu, Jing-jing; Du, Rui-ping; Gao, Min; Sui, Yao-qiang; Xiu, Lei; Wang, Xiao

    2014-01-01

    Silage making has become a significant method of forage conservation worldwide. To determine how tomato pomace (TP) may be used effectively as animal feed, it was ensilaged for 90 days and microbiology counts, fermentation characteristics and chemical composition of tomato pomace silage (TPS) were evaluated at the 30th, 60th, and 90th days, respectively. In addition, 103 lactic acid bacteria were isolated from TPS. Based on the phenotypic and chemotaxonomic characteristics, 16S rDNA sequence and carbohydrate fermentation tests, the isolates were identified as 17 species namely: Lactobacillus coryniformis subsp. torquens (0.97%), Lactobacillus pontis (0.97%), Lactobacillus hilgardii (0.97%), Lactobacillus pantheris (0.97%), Lactobacillus amylovorus (1.9%), Lactobacillus panis (1.9%), Lactobacillus vaginalis (1.9%), Lactobacillus rapi (1.9%), Lactobacillus buchneri (2.9%), Lactobacillus parafarraginis (2.9%), Lactobacillus helveticus (3.9%), Lactobacillus camelliae (3.9%), Lactobacillus fermentum (5.8%), Lactobacillus manihotivorans (6.8%), Lactobacillus plantarum (10.7%), Lactobacillus harbinensis (16.5%) and Lactobacillus paracasei subsp. paracasei (35.0%). This study has shown that TP can be well preserved for 90 days by ensilaging and that TPS is not only rich in essential nutrients, but that physiological and biochemical properties of the isolates could provide a platform for future design of lactic acid bacteria (LAB) inoculants aimed at improving the fermentation quality of silage. PMID:25049999

  13. Biodegradation of Asphalt Cement-20 by Aerobic Bacteria

    PubMed Central

    Pendrys, John P.

    1989-01-01

    Seven gram-negative, aerobic bacteria were isolated from a mixed culture enriched for asphalt-degrading bacteria. The predominant genera of these isolates were Pseudomonas, Acinetobacter, Alcaligenes, Flavimonas, and Flavobacterium. The mixed culture preferentially degraded the saturate and naphthene aromatic fractions of asphalt cement-20. A residue remained on the surface which was resistant to biodegradation and protected the underlying asphalt from biodegradation. The most potent asphalt-degrading bacterium, Acinetobacter calcoaceticus NAV2, excretes an emulsifier which is capable of emulsifying the saturate and naphthene aromatic fractions of asphalt cement-20. This emulsifier is not denatured by phenol. PMID:16347928

  14. Genomic reconstruction of transcriptional regulatory networks in lactic acid bacteria

    PubMed Central

    2013-01-01

    Background Genome scale annotation of regulatory interactions and reconstruction of regulatory networks are the crucial problems in bacterial genomics. The Lactobacillales order of bacteria collates various microorganisms having a large economic impact, including both human and animal pathogens and strains used in the food industry. Nonetheless, no systematic genome-wide analysis of transcriptional regulation has been previously made for this taxonomic group. Results A comparative genomics approach was used for reconstruction of transcriptional regulatory networks in 30 selected genomes of lactic acid bacteria. The inferred networks comprise regulons for 102 orthologous transcription factors (TFs), including 47 novel regulons for previously uncharacterized TFs. Numerous differences between regulatory networks of the Streptococcaceae and Lactobacillaceae groups were described on several levels. The two groups are characterized by substantially different sets of TFs encoded in their genomes. Content of the inferred regulons and structure of their cognate TF binding motifs differ for many orthologous TFs between the two groups. Multiple cases of non-orthologous displacements of TFs that control specific metabolic pathways were reported. Conclusions The reconstructed regulatory networks substantially expand the existing knowledge of transcriptional regulation in lactic acid bacteria. In each of 30 studied genomes the obtained regulatory network contains on average 36 TFs and 250 target genes that are mostly involved in carbohydrate metabolism, stress response, metal homeostasis and amino acids biosynthesis. The inferred networks can be used for genetic experiments, functional annotations of genes, metabolic reconstruction and evolutionary analysis. All reconstructed regulons are captured within the Streptococcaceae and Lactobacillaceae collections in the RegPrecise database (http://regprecise.lbl.gov). PMID:23398941

  15. Protection of probiotic bacteria in a synbiotic matrix following aerobic storage at 4 °C.

    PubMed

    Chaluvadi, S; Hotchkiss, A T; Call, J E; Luchansky, J B; Phillips, J G; Liu, Ls; Yam, K L

    2012-09-01

    The survival of single strains of Bifidobacterium breve, Bifidobacterium longum, Lactobacillus acidophilus, and Lactobacillus reuteri was investigated in synbiotics that included 10 mg/ml of fructo-oligosaccharides, inulin and pectic-oligosaccharides in an alginate matrix under refrigerated (4 °C) aerobic storage conditions. When the matrices were cross-linked with calcium (45 mM), 102-103 cfu/ml of L. acidophilus and L. reuteri, and 0-103 cfu/ml of B. breve and B. longum survived refrigerated aerobic storage for 28 days. Following refrigerated storage, acetic (3-9 mM), butyric (0-2 mM), propionic (5-16 mM) and lactic acids (1-48 mM) were produced during the growth of probiotics in BHI broth at 37 °C, suggesting their metabolic activity after storage was stressed. When calcium cross-linking was not used in synbiotics, the matrix remained more gel-like after inoculation when compared to the calcium cross-linked matrix. At least 107 cfu/ml of probiotic bacteria survived after 21 days of storage within these gel-like alginate matrices. Significantly higher levels of B. breve, L. acidophilus and L. reuteri were obtained from the synbiotic matrices supplemented with fructo-oligosaccharides, inulin and pectic-oligosaccharides compared to alginate alone. B. longum survival was the same (~7 logs) in all gel-like synbiotic matrices. These results show that synbiotics protected probiotic bacteria and extended their shelf-life under refrigerated aerobic conditions. Synbiotics represent a viable delivery vehicle for health-promoting bacteria.

  16. Identification of lactic acid bacteria isolated from corn stovers.

    PubMed

    Pang, Huili; Zhang, Meng; Qin, Guangyong; Tan, Zhongfang; Li, Zongwei; Wang, Yanping; Cai, Yimin

    2011-10-01

    One hundred and twenty-six strains were isolated from corn stover in Henan Province, China, of which 105 isolates were considered to be lactic acid bacteria (LAB) according to Gram-positive, catalase-negative and mainly metabolic lactic acid product. Analysis of the 16S ribosomal DNA sequence of 21 representative strains was used to confirm the presence of the predominant groups and to determine the phylogenetic affiliation of isolates. The sequences from the various LAB isolates showed high degrees of similarity to those of the GenBank type strains between 99.4% and 100%. The prevalent LAB, predominantly Lactobacillus (85.6%), consisted of L. plantarum (33.3%), L. pentosus (28.6%) and L. brevis (23.7%). Other LAB species as Leuconostoc lactis (4.8%), Weissella cibaria (4.8%) and Enterococcus mundtii (4.8%) also presented in corn stover. The present study is the first to fully document corn stover-associated LAB involved in the silage fermentation. The identification results revealed LAB composition inhabiting corn stover and enabling the future design of appropriate inoculants aimed at improving the fermentation quality of silage.

  17. Growth of nitrite-oxidizing bacteria by aerobic hydrogen oxidation.

    PubMed

    Koch, Hanna; Galushko, Alexander; Albertsen, Mads; Schintlmeister, Arno; Gruber-Dorninger, Christiane; Lücker, Sebastian; Pelletier, Eric; Le Paslier, Denis; Spieck, Eva; Richter, Andreas; Nielsen, Per H; Wagner, Michael; Daims, Holger

    2014-08-29

    The bacterial oxidation of nitrite to nitrate is a key process of the biogeochemical nitrogen cycle. Nitrite-oxidizing bacteria are considered a highly specialized functional group, which depends on the supply of nitrite from other microorganisms and whose distribution strictly correlates with nitrification in the environment and in wastewater treatment plants. On the basis of genomics, physiological experiments, and single-cell analyses, we show that Nitrospira moscoviensis, which represents a widely distributed lineage of nitrite-oxidizing bacteria, has the genetic inventory to utilize hydrogen (H2) as an alternative energy source for aerobic respiration and grows on H2 without nitrite. CO2 fixation occurred with H2 as the sole electron donor. Our results demonstrate a chemolithoautotrophic lifestyle of nitrite-oxidizing bacteria outside the nitrogen cycle, suggesting greater ecological flexibility than previously assumed.

  18. Progress in engineering acid stress resistance of lactic acid bacteria.

    PubMed

    Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2014-02-01

    Lactic acid bacteria (LAB) are widely used for the production of a variety of fermented foods, and are considered as probiotic due to their health-promoting effect. However, LAB encounter various environmental stresses both in industrial fermentation and application, among which acid stress is one of the most important survival challenges. Improving the acid stress resistance may contribute to the application and function of probiotic action to the host. Recently, the advent of genomics, functional genomics and high-throughput technologies have allowed for the understanding of acid tolerance mechanisms at a systems level, and many method to improve acid tolerance have been developed. This review describes the current progress in engineering acid stress resistance of LAB. Special emphasis is placed on engineering cellular microenvironment (engineering amino acid metabolism, introduction of exogenous biosynthetic capacity, and overproduction of stress response proteins) and maintaining cell membrane functionality. Moreover, strategies to improve acid tolerance and the related physiological mechanisms are also discussed.

  19. Lactic acid bacteria as adjuvants for sublingual allergy vaccines.

    PubMed

    Van Overtvelt, Laurence; Moussu, Helene; Horiot, Stéphane; Samson, Sandrine; Lombardi, Vincent; Mascarell, Laurent; van de Moer, Ariane; Bourdet-Sicard, Raphaëlle; Moingeon, Philippe

    2010-04-09

    We compared immunomodulatory properties of 11 strains of lactic acid bacteria as well as their capacity to enhance sublingual immunotherapy efficacy in a murine asthma model. Two types of bacterial strains were identified, including: (i) potent inducers of IL-12p70 and IL-10 in dendritic cells, supporting IFN-gamma and IL-10 production in CD4+ T cells such as Lactobacillus helveticus; (ii) pure Th1 inducers such as L. casei. Sublingual administration in ovalbumin-sensitized mice of L. helveticus, but not L. casei, reduced airways hyperresponsiveness, bronchial inflammation and proliferation of specific T cells in cervical lymph nodes. Thus, probiotics acting as a Th1/possibly Treg, but not Th1 adjuvant, potentiate tolerance induction via the sublingual route.

  20. Variations in prebiotic oligosaccharide fermentation by intestinal lactic acid bacteria.

    PubMed

    Endo, Akihito; Nakamura, Saki; Konishi, Kenta; Nakagawa, Junichi; Tochio, Takumi

    2016-01-01

    Prebiotic oligosaccharides confer health benefits on the host by modulating the gut microbiota. Intestinal lactic acid bacteria (LAB) are potential targets of prebiotics; however, the metabolism of oligosaccharides by LAB has not been fully characterized. Here, we studied the metabolism of eight oligosaccharides by 19 strains of intestinal LAB. Among the eight oligosaccharides used, 1-kestose, lactosucrose and galactooligosaccharides (GOSs) led to the greatest increases in the numbers of the strains tested. However, mono- and disaccharides accounted for more than half of the GOSs used, and several strains only metabolized the mono- and di-saccharides in GOSs. End product profiles indicated that the amounts of lactate produced were generally consistent with the bacterial growth recorded. Oligosaccharide profiling revealed the interesting metabolic manner in Lactobacillus paracasei strains, which metabolized all oligosaccharides, but left sucrose when cultured with fructooligosaccharides. The present study clearly indicated that the prebiotic potential of each oligosaccharide differs.

  1. Antiviral potential of lactic acid bacteria and their bacteriocins.

    PubMed

    Al Kassaa, I; Hober, D; Hamze, M; Chihib, N E; Drider, D

    2014-12-01

    Emerging resistance to antiviral agents is a growing public health concern worldwide as it was reported for respiratory, sexually transmitted and enteric viruses. Therefore, there is a growing demand for new, unconventional antiviral agents which may serve as an alternative to the currently used drugs. Meanwhile, published literature continues shedding the light on the potency of lactic acid bacteria (LAB) and their bacteriocins as antiviral agents. Health-promoting LAB probiotics may exert their antiviral activity by (1) direct probiotic-virus interaction; (2) production of antiviral inhibitory metabolites; and/or (3) via stimulation of the immune system. The aim of this review was to highlight the antiviral activity of LAB and substances they produce with antiviral activity.

  2. Determination of peroxy radical-scavenging of lactic acid bacteria.

    PubMed

    Stecchini, M L; Del Torre, M; Munari, M

    2001-02-28

    Responses of lactic acid bacteria (LAB) to peroxy radicals generated via thermal (40 degrees C) decomposition of the diazocompound 2,2,-azo-bis (2-amidinopropane) dihydrochloride (ABAP), were studied. In general, LAB displayed survival curves with shoulders and tails indicative of 'multihit' killing by exposure to peroxy radicals. One strain, Lactococcus lactis subsp. lactis DIP15, producing a slope of 0.0105 in the kinetic analysis when exposed to 4 mM ABAP, exhibited a measurable antioxidant capacity. The other LAB failed to show any significant antioxidant capacity. The antioxidant capacity of strain DIP15 remained constant after cells have been heat-treated, suggesting that compounds bearing free radical scavenging capacity are rather stable.

  3. Probiotic lactic acid bacteria detoxify N-nitrosodimethylamine.

    PubMed

    Nowak, Adriana; Kuberski, Sławomir; Libudzisz, Zdzisława

    2014-01-01

    Humans can be exposed to N-nitroso compounds (NOCs) due to many environmental sources, as well as endogenous formation. The main nitrosamine found in food products and also synthesised in vivo by intestinal microbiota is N-nitrosodimethylamine (NDMA). It can cause cancer of the stomach, kidney and colon. The effect of four probiotic Lactobacillus strains on NDMA was studied under different culture conditions (24 h in MRS, 168 h in modified MRS N, and 168 h in phosphate buffer). HPLC and GC-TEA methods were used for NDMA determination in supernatants. The influence of lactic acid bacteria on NDMA genotoxicity was investigated by means of the comet assay. Additionally, the effect of NDMA (2-100 µg ml⁻¹) on the growth and survival of the probiotic strains was studied. The results indicate that the bacteria decreased NDMA concentration by up to 50%, depending on the culture conditions, time of incubation, NDMA concentration, pH and bacterial strain. Lb. brevis 0945 lowered the concentration and genotoxicity of NDMA most effectively by up to 50%. This could be due to either adsorption or metabolism. The growth and survival of the bacteria was not affected by any of the tested NDMA concentrations.

  4. Genome level analysis of bacteriocins of lactic acid bacteria.

    PubMed

    Singh, Neetigyata Pratap; Tiwari, Abhay; Bansal, Ankiti; Thakur, Shruti; Sharma, Garima; Gabrani, Reema

    2015-06-01

    Bacteriocins are antimicrobial peptides which are ribosomally synthesized by mainly all bacterial species. LABs (lactic acid bacteria) are a diverse group of bacteria that include around 20 genera of various species. Though LABs have a tremendous potential for production of anti-microbial peptides, this group of bacteria is still underexplored for bacteriocins. To study the diversity among bacteriocin encoding clusters and the putative bacteriocin precursors, genome mining was performed on 20 different species of LAB not reported to be bacteriocin producers. The phylogenetic tree of gyrB, rpoB, and 16S rRNA were constructed using MEGA6 software to analyze the diversity among strains. Putative bacteriocins operons identified were found to be diverse and were further characterized on the basis of physiochemical properties and the secondary structure. The presence of at least two cysteine residues in most of the observed putative bacteriocins leads to disulphide bond formation and provide stability. Our data suggests that LABs are prolific source of low molecular weight non modified peptides.

  5. Cell wall structure and function in lactic acid bacteria

    PubMed Central

    2014-01-01

    The cell wall of Gram-positive bacteria is a complex assemblage of glycopolymers and proteins. It consists of a thick peptidoglycan sacculus that surrounds the cytoplasmic membrane and that is decorated with teichoic acids, polysaccharides, and proteins. It plays a major role in bacterial physiology since it maintains cell shape and integrity during growth and division; in addition, it acts as the interface between the bacterium and its environment. Lactic acid bacteria (LAB) are traditionally and widely used to ferment food, and they are also the subject of more and more research because of their potential health-related benefits. It is now recognized that understanding the composition, structure, and properties of LAB cell walls is a crucial part of developing technological and health applications using these bacteria. In this review, we examine the different components of the Gram-positive cell wall: peptidoglycan, teichoic acids, polysaccharides, and proteins. We present recent findings regarding the structure and function of these complex compounds, results that have emerged thanks to the tandem development of structural analysis and whole genome sequencing. Although general structures and biosynthesis pathways are conserved among Gram-positive bacteria, studies have revealed that LAB cell walls demonstrate unique properties; these studies have yielded some notable, fundamental, and novel findings. Given the potential of this research to contribute to future applied strategies, in our discussion of the role played by cell wall components in LAB physiology, we pay special attention to the mechanisms controlling bacterial autolysis, bacterial sensitivity to bacteriophages and the mechanisms underlying interactions between probiotic bacteria and their hosts. PMID:25186919

  6. Who will win the race in childrens' oral cavities? Streptococcus mutans or beneficial lactic acid bacteria?

    PubMed

    Güngör, Ö E; Kırzıoğlu, Z; Dinçer, E; Kıvanç, M

    2013-09-01

    Adhesion to oral soft and hard tissue is crucial for bacterial colonisation in the mouth. The aim of this work was to select strains of oral lactic acid bacteria that could be used as probiotics for oral health. To this end, the adhesive properties of some lactic acid bacteria were investigated. Seventeen lactic acid bacteria including two Streptococcus mutans strains were isolated from the oral cavity of healthy children, while other strains were isolated from fermented meat products. The bacterial strains were applied to teeth surfaces covered with saliva or without saliva. A significant diversity in adhesion capacity to teeth surfaces among the lactic acid bacteria was observed. Lactic acid bacteria isolated from the oral cavity adhered the best to teeth surfaces covered with saliva, whereas lactic acid bacteria isolated from fermented meat samples adhered the best to tooth surface without saliva. All strains of lactic acid bacteria were able to reduce the number of S. mutans cells, in particular on saliva-coated tooth surface. Therefore, they might have potential as probiotics for the oral cavity.

  7. Adhesion Properties of Lactic Acid Bacteria on Intestinal Mucin

    PubMed Central

    Nishiyama, Keita; Sugiyama, Makoto; Mukai, Takao

    2016-01-01

    Lactic acid bacteria (LAB) are Gram-positive bacteria that are natural inhabitants of the gastrointestinal (GI) tracts of mammals, including humans. Since Mechnikov first proposed that yogurt could prevent intestinal putrefaction and aging, the beneficial effects of LAB have been widely demonstrated. The region between the duodenum and the terminal of the ileum is the primary region colonized by LAB, particularly the Lactobacillus species, and this region is covered by a mucus layer composed mainly of mucin-type glycoproteins. The mucus layer plays a role in protecting the intestinal epithelial cells against damage, but is also considered to be critical for the adhesion of Lactobacillus in the GI tract. Consequently, the adhesion exhibited by lactobacilli on mucin has attracted attention as one of the critical factors contributing to the persistent beneficial effects of Lactobacillus in a constantly changing intestinal environment. Thus, understanding the interactions between Lactobacillus and mucin is crucial for elucidating the survival strategies of LAB in the GI tract. This review highlights the properties of the interactions between Lactobacillus and mucin, while concomitantly considering the structure of the GI tract from a histochemical perspective. PMID:27681930

  8. Perspectives of engineering lactic acid bacteria for biotechnological polyol production.

    PubMed

    Monedero, Vicente; Pérez-Martínez, Gaspar; Yebra, María J

    2010-04-01

    Polyols are sugar alcohols largely used as sweeteners and they are claimed to have several health-promoting effects (low-caloric, low-glycemic, low-insulinemic, anticariogenic, and prebiotic). While at present chemical synthesis is the only strategy able to assure the polyol market demand, the biotechnological production of polyols has been implemented in yeasts, fungi, and bacteria. Lactic acid bacteria (LAB) are a group of microorganisms particularly suited for polyol production as they display a fermentative metabolism associated with an important redox modulation and a limited biosynthetic capacity. In addition, LAB participate in food fermentation processes, where in situ production of polyols during fermentation may be useful in the development of novel functional foods. Here, we review the polyol production by LAB, focusing on metabolic engineering strategies aimed to redirect sugar fermentation pathways towards the synthesis of biotechnologically important sugar alcohols such as sorbitol, mannitol, and xylitol. Furthermore, possible approaches are presented for engineering new fermentation routes in LAB for production of arabitol, ribitol, and erythritol.

  9. Aerobic sulfur-oxidizing bacteria: Environmental selection and diversification

    NASA Technical Reports Server (NTRS)

    Caldwell, D.

    1985-01-01

    Sulfur-oxidizing bacteria oxidize reduced inorganic compounds to sulfuric acid. Lithotrophic sulfur oxidizer use the energy obtained from oxidation for microbial growth. Heterotrophic sulfur oxidizers obtain energy from the oxidation of organic compounds. In sulfur-oxidizing mixotrophs energy are derived either from the oxidation of inorganic or organic compounds. Sulfur-oxidizing bacteria are usually located within the sulfide/oxygen interfaces of springs, sediments, soil microenvironments, and the hypolimnion. Colonization of the interface is necessary since sulfide auto-oxidizes and because both oxygen and sulfide are needed for growth. The environmental stresses associated with the colonization of these interfaces resulted in the evolution of morphologically diverse and unique aerobic sulfur oxidizers.

  10. Glycerol metabolism and bitterness producing lactic acid bacteria in cidermaking.

    PubMed

    Garai-Ibabe, G; Ibarburu, I; Berregi, I; Claisse, O; Lonvaud-Funel, A; Irastorza, A; Dueñas, M T

    2008-02-10

    Several lactic acid bacteria were isolated from bitter tasting ciders in which glycerol was partially removed. The degradation of glycerol via glycerol dehydratase pathway was found in 22 out of 67 isolates. The confirmation of glycerol degradation by this pathway was twofold: showing their glycerol dehydratase activity and detecting the presence of the corresponding gene by a PCR method. 1,3-propanediol (1,3-PDL) and 3-hydroxypropionic acid (3-HP) were the metabolic end-products of glycerol utilization, and the accumulation of the acrolein precursor 3-hydroxypropionaldehyde (3-HPA) was also detected in most of them. The strain identification by PCR-DGGE rpoB showed that Lactobacillus collinoides was the predominant species and only 2 belonged to Lactobacillus diolivorans. Environmental conditions conducting to 3-HPA accumulation in cidermaking were studied by varying the fructose concentration, pH and incubation temperature in L. collinoides 17. This strain failed to grow with glycerol as sole carbon source and the addition of fructose enhanced both growth and glycerol degradation. Regarding end-products of glycerol metabolism, 1,3-PDL was always the main end-product in all environmental conditions assayed, the only exception being the culture with 5.55 mM fructose, where equimolar amounts of 1,3-PDL and 3-HP were found. The 3-HPA was transitorily accumulated in the culture medium under almost all culture conditions, the degradation rate being notably slower at 15 degrees C. However, no disappearance of 3-HPA was found at pH 3.6, a usual value in cider making. After sugar exhaustion, L. collinoides 17 oxidated lactic acid and/or mannitol to obtain energy and these oxidations were accompanied by the removal of the toxic 3-HPA increasing the 1,3-PDL, 3-HP and acetic acid contents.

  11. Antibiotic resistance of lactic acid bacteria isolated from Chinese yogurts.

    PubMed

    Zhou, N; Zhang, J X; Fan, M T; Wang, J; Guo, G; Wei, X Y

    2012-09-01

    The aim of this study was to evaluate the susceptibility of 43 strains of lactic acid bacteria, isolated from Chinese yogurts made in different geographical areas, to 11 antibiotics (ampicillin, penicillin G, roxithromycin, chloramphenicol, tetracycline, chlortetracycline, lincomycin, kanamycin, streptomycin, neomycin, and gentamycin). The 43 isolates (18 Lactobacillus bulgaricus and 25 Streptococcus thermophilus) were identified at species level and were typed by random amplified polymorphic DNA analysis. Thirty-five genotypically different strains were detected and their antimicrobial resistance to 11 antibiotics was determined using the agar dilution method. Widespread resistance to ampicillin, chloramphenicol, chlortetracycline, tetracyclines, lincomycin, streptomycin, neomycin, and gentamycin was found among the 35 strains tested. All of the Strep. thermophilus strains tested were susceptible to penicillin G and roxithromycin, whereas 23.5 and 64.7% of Lb. bulgaricus strains, respectively, were resistant. All of the Strep. thermophilus and Lb. bulgaricus strains were found to be resistant to kanamycin. The presence of the corresponding resistance genes in the resistant isolates was investigated through PCR, with the following genes detected: tet(M) in 1 Lb. bulgaricus and 2 Strep. thermophilus isolates, ant(6) in 2 Lb. bulgaricus and 2 Strep. thermophilus isolates, and aph(3')-IIIa in 5 Lb. bulgaricus and 2 Strep. thermophilus isolates. The main threat associated with these bacteria is that they may transfer resistance genes to pathogenic bacteria, which has been a major cause of concern to human and animal health. To our knowledge, the aph(3')-IIIa and ant(6) genes were found in Lb. bulgaricus and Strep. thermophilus for the first time. Further investigations are required to analyze whether the genes identified in Lb. bulgaricus and Strep. thermophilus isolates might be horizontally transferred to other species.

  12. Interactions between Cooccurring Lactic Acid Bacteria in Honey Bee Hives.

    PubMed

    Rokop, Z P; Horton, M A; Newton, I L G

    2015-10-01

    In contrast to the honey bee gut, which is colonized by a few characteristic bacterial clades, the hive of the honey bee is home to a diverse array of microbes, including many lactic acid bacteria (LAB). In this study, we used culture, combined with sequencing, to sample the LAB communities found across hive environments. Specifically, we sought to use network analysis to identify microbial hubs sharing nearly identical operational taxonomic units, evidence which may indicate cooccurrence of bacteria between environments. In the process, we identified interactions between noncore bacterial members (Fructobacillus and Lactobacillaceae) and honey bee-specific "core" members. Both Fructobacillus and Lactobacillaceae colonize brood cells, bee bread, and nectar and may serve the role of pioneering species, establishing an environment conducive to the inoculation by honey bee core bacteria. Coculture assays showed that these noncore bacterial members promote the growth of honey bee-specific bacterial species. Specifically, Fructobacillus by-products in spent medium supported the growth of the Firm-5 honey bee-specific clade in vitro. Metabolic characterization of Fructobacillus using carbohydrate utilization assays revealed that this strain is capable of utilizing the simple sugars fructose and glucose, as well as the complex plant carbohydrate lignin. We tested Fructobacillus for antibiotic sensitivity and found that this bacterium, which may be important for establishment of the microbiome, is sensitive to the commonly used antibiotic tetracycline. Our results point to the possible significance of "noncore" and environmental microbial community members in the modulation of honey bee microbiome dynamics and suggest that tetracycline use by beekeepers should be limited.

  13. Aerobic salivary bacteria in wild and captive Komodo dragons.

    PubMed

    Montgomery, Joel M; Gillespie, Don; Sastrawan, Putra; Fredeking, Terry M; Stewart, George L

    2002-07-01

    During the months of November 1996, August 1997, and March 1998, saliva and plasma samples were collected for isolation of aerobic bacteria from 26 wild and 13 captive Komodo dragons (Varanus komodoensis). Twenty-eight Gram-negative and 29 Gram-positive species of bacteria were isolated from the saliva of the 39 Komodo dragons. A greater number of wild than captive dragons were positive for both Gram-negative and Gram-positive bacteria. The average number of bacterial species within the saliva of wild dragons was 46% greater than for captive dragons. While Escherichia coli was the most common bacterium isolated from the saliva of wild dragons, this species was not present in captive dragons. The most common bacteria isolated from the saliva of captive dragons were Staphylococcus capitis and Staphylococcus capitis and Staphylococcus caseolyticus, neither of which were found in wild dragons. High mortality was seen among mice injected with saliva from wild dragons and the only bacterium isolated from the blood of dying mice was Pasteurella multocida. A competitive inhibition enzyme-linked immunosorbent assay revealed the presence of anti-Pasteurella antibody in the plasma of Komodo dragons. Four species of bacteria isolated from dragon saliva showed resistance to one or more of 16 antimicrobics tested. The wide variety of bacteria demonstrated in the saliva of the Komodo dragon in this study, at least one species of which was highly lethal in mice and 54 species of which are known pathogens, support the observation that wounds inflicted by this animal are often associated with sepsis and subsequent bacteremia in prey animals.

  14. Bacillus spp. produce antibacterial activities against lactic acid bacteria that contaminate fuel ethanol plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactic acid bacteria (LAB) frequently contaminate commercial fuel ethanol fermentations, reducing yields and decreasing profitability of biofuel production. Microorganisms from environmental sources in different geographic regions of Thailand were tested for antibacterial activity against LAB. Fou...

  15. Metabolic strategies of beer spoilage lactic acid bacteria in beer.

    PubMed

    Geissler, Andreas J; Behr, Jürgen; von Kamp, Kristina; Vogel, Rudi F

    2016-01-04

    Beer contains only limited amounts of readily fermentable carbohydrates and amino acids. Beer spoilage lactic acid bacteria (LAB) have to come up with metabolic strategies in order to deal with selective nutrient content, high energy demand of hop tolerance mechanisms and a low pH. The metabolism of 26 LAB strains of 6 species and varying spoilage potentialwas investigated in order to define and compare their metabolic capabilities using multivariate statistics and outline possible metabolic strategies. Metabolic capabilities of beer spoilage LAB regarding carbohydrate and amino acids did not correlate with spoilage potential, but with fermentation type (heterofermentative/homofermentative) and species. A shift to mixed acid fermentation by homofermentative (hof) Pediococcus claussenii and Lactobacillus backii was observed as a specific feature of their growth in beer. For heterofermentative (hef) LAB a mostly versatile carbohydrate metabolism could be demonstrated, supplementing the known relevance of organic acids for their growth in beer. For hef LAB a distinct amino acid metabolism, resulting in biogenic amine production, was observed, presumably contributing to energy supply and pH homeostasis.

  16. Molecular screening of wine lactic acid bacteria degrading hydroxycinnamic acids.

    PubMed

    de las Rivas, Blanca; Rodríguez, Héctor; Curiel, José Antonio; Landete, José María; Muñoz, Rosario

    2009-01-28

    The potential to produce volatile phenols from hydroxycinnamic acids was investigated for lactic acid bacteria (LAB) isolated from Spanish grape must and wine. A PCR assay was developed for the detection of LAB that potentially produce volatile phenols. Synthetic degenerate oligonucleotides for the specific detection of the pdc gene encoding a phenolic acid decarboxylase were designed. The pdc PCR assay amplifies a 321 bp DNA fragment from phenolic acid decarboxylase. The pdc PCR method was applied to 85 strains belonging to the 6 main wine LAB species. Lactobacillus plantarum, Lactobacillus brevis, and Pediococcus pentosaceus strains produce a positive response in the pdc PCR assay, whereas Oenococcus oeni, Lactobacillus hilgardii, and Leuconostoc mesenteroides strains did not produce the expected PCR product. The production of vinyl and ethyl derivatives from hydroxycinnamic acids in culture media was determined by high-performance liquid chromatography. A relationship was found between pdc PCR amplification and volatile phenol production, so that the LAB strains that gave a positive pdc PCR response produce volatile phenols, whereas strains that did not produce a PCR amplicon did not produce volatile phenols. The proposed method could be useful for a preliminary identification of LAB strains able to produce volatile phenols in wine.

  17. Isolation and characterisation of lactic acid bacteria from donkey milk.

    PubMed

    Soto Del Rio, Maria de Los Dolores; Andrighetto, Christian; Dalmasso, Alessandra; Lombardi, Angiolella; Civera, Tiziana; Bottero, Maria Teresa

    2016-08-01

    During the last years the interest in donkey milk has increased significantly mainly because of its compelling functional elements. Even if the composition and nutritional properties of donkey milk are known, its microbiota is less studied. This Research Communication aimed to provide a comprehensive characterisation of the lactic acid bacteria in raw donkey milk. RAPD-PCR assay combined with 16S rDNA sequencing analysis were used to describe the microbial diversity of several donkey farms in the North West part of Italy. The more frequently detected species were: Lactobacillus paracasei, Lactococcus lactis and Carnobacterium maltaromaticum. Less abundant genera were Leuconostoc, Enterococcus and Streptococcus. The yeast Kluyveromyces marxianus was also isolated. The bacterial and biotype distribution notably diverged among the farms. Several of the found species, not previously detected in donkey milk, could have an important probiotic activity and biotechnological potential. This study represents an important insight to the ample diversity of the microorganisms present in the highly selective ecosystem of raw donkey milk.

  18. Lactic acid bacteria in dried vegetables and spices.

    PubMed

    Säde, Elina; Lassila, Elisa; Björkroth, Johanna

    2016-02-01

    Spices and dried vegetable seasonings are potential sources of bacterial contamination for foods. However, little is known about lactic acid bacteria (LAB) in spices and dried vegetables, even though certain LAB may cause food spoilage. In this study, we enumerated LAB in 104 spices and dried vegetables products aimed for the food manufacturing industry. The products were obtained from a spice wholesaler operating in Finland, and were sampled during a one-year period. We picked isolates (n = 343) for species identification based on numerical analysis of their ribotyping patterns and comparing them with the corresponding patterns of LAB type strains. We found LAB at levels >2 log CFU/g in 68 (65%) of the samples, with the highest counts detected from dried onion products and garlic powder with counts ranging from 4.24 to 6.64 log CFU/g. The LAB identified were predominantly Weissella spp. (61%) and Pediococcus spp. (15%) with Weissella confusa, Weissella cibaria, Weissella paramesenteroides, Pediococcus acidilactici and Pediococcus pentosaceus being the species identified. Other species identified belonged to the genera of Enterococcus spp. (8%), Leuconostoc spp. (6%) and Lactobacillus spp. (2%). Among the LAB identified, Leuconostoc citreum, Leuconostoc mesenteroides and W. confusa have been associated with food spoilage. Our findings suggest that spices and dried vegetables are potential sources of LAB contamination in the food industry.

  19. Fermentation of aqueous plant seed extracts by lactic acid bacteria

    SciTech Connect

    Schafner, D.W.; Beuchat, R.L.

    1986-05-01

    The effects of lactic acid bacterial fermentation on chemical and physical changes in aqueous extracts of cowpea (Vigna unguiculata), peanut (Arachis hypogea), soybean (Glycine max), and sorghum (Sorghum vulgare) were studied. The bacteria investigated were Lactobacillus helveticus, L. delbrueckii, L. casei, L. bulgaricus, L. acidophilus, and Streptococcus thermophilus. Organisms were inoculated individually into all of the seed extracts; L. bulgaricus and S. thermophilus were also evaluated together as inocula for fermenting the legume extracts. During fermentation, bacterial population and changes in titratable acidity, pH, viscosity, and color were measured over a 72 h period at 37 degrees C. Maximum bacterial populations, titratable acidity, pH, and viscosity varied depending upon the type of extract and bacterial strain. The maximum population of each organism was influenced by fermentable carbohydrates, which, in turn, influenced acid production and change in pH. Change in viscosity was correlated with the amount of protein and titratable acidity of products. Color was affected by pasteurization treatment and fermentation as well as the source of extract. In the extracts inoculated simultaneously with L. bulgaricus and S. thermophilus, a synergistic effect resulted in increased bacterial populations, titratable acidity, and viscosity, and decreased pH in all the legume extracts when compared to the extracts fermented with either of these organisms individually. Fermented extracts offer potential as substitutes for cultured dairy products. 24 references.

  20. A gene network engineering platform for lactic acid bacteria.

    PubMed

    Kong, Wentao; Kapuganti, Venkata S; Lu, Ting

    2016-02-29

    Recent developments in synthetic biology have positioned lactic acid bacteria (LAB) as a major class of cellular chassis for applications. To achieve the full potential of LAB, one fundamental prerequisite is the capacity for rapid engineering of complex gene networks, such as natural biosynthetic pathways and multicomponent synthetic circuits, into which cellular functions are encoded. Here, we present a synthetic biology platform for rapid construction and optimization of large-scale gene networks in LAB. The platform involves a copy-controlled shuttle for hosting target networks and two associated strategies that enable efficient genetic editing and phenotypic validation. By using a nisin biosynthesis pathway and its variants as examples, we demonstrated multiplex, continuous editing of small DNA parts, such as ribosome-binding sites, as well as efficient manipulation of large building blocks such as genes and operons. To showcase the platform, we applied it to expand the phenotypic diversity of the nisin pathway by quickly generating a library of 63 pathway variants. We further demonstrated its utility by altering the regulatory topology of the nisin pathway for constitutive bacteriocin biosynthesis. This work demonstrates the feasibility of rapid and advanced engineering of gene networks in LAB, fostering their applications in biomedicine and other areas.

  1. Comparative genomics of phages and prophages in lactic acid bacteria.

    PubMed

    Desiere, Frank; Lucchini, Sacha; Canchaya, Carlos; Ventura, Marco; Brüssow, Harald

    2002-08-01

    Comparative phage genomics has become possible due to the availability of more than 100 complete phage genome sequences and the development of powerful bioinformatics tools. This technology, profiting from classical molecular-biology knowledge, has opened avenues of research for topics, which were difficult to address in the past. Now, it is possible to retrace part of the evolutionary history of phage modules by comparative genomics. The diagnosis of relatedness is hereby not uniquely based on sequence similarity alone, but includes topological considerations of genome organization. Detailed transcription maps have allowed in silico predictions of genome organization to be verified and refined. This comparative knowledge is providing the basis for a new taxonomic classification concept for bacteriophages infecting low G + C-content Gram-positive bacteria based on the genetic organization of the structural gene module. An Sfi21-like and an Sfi11-like genus of Siphoviridae is proposed. The gene maps of many phages show remarkable synteny in their structural genes defining a lambda super-group within Siphoviridae. A hierarchy of relatedness within the lambda super-group suggests elements of vertical evolution in Siphoviridae. Tailed phages are the result of both vertical and horizontal evolution and are thus fascinating objects for the study of molecular evolution. Prophage sequences integrated into the genomes of their bacterial host present theoretical challenges for evolutionary biologists. Prophages represent up to 10% of the genome in some LAB. In pathogenic streptococci prophages confer genes of selective value for the lysogenic cell. The lysogenic conversion genes are located between the lysin gene and the right phage attachment site. Non-attributed genes were found at the same genome position of prophages from lactic streptococci. These genes belong to the few prophage genes transcribed in the lysogen. Prophages from dairy bacteria might therefore also

  2. Characterization of the spoilage lactic acid bacteria in "sliced vacuum-packed cooked ham".

    PubMed

    Kalschne, Daneysa Lahis; Womer, Rute; Mattana, Ademir; Sarmento, Cleonice Mendes Pereira; Colla, Luciane Maria; Colla, Eliane

    2015-03-01

    The lactic acid bacteria are involved with food fermentation and in such cases with food spoilage. Considering the need to reduce the lactic acid bacteria growth in meat products, the aim of this work was to enumerated and investigated the lactic acid bacteria present on sliced vacuum-packed cooked ham stored at 4 °C and 8 °C for 45 days by phenotypic and molecular techniques. The quantification showed that the lactic acid bacteria were present from the first day with mean count of 1.98 log cfu/g for the four batches analyzed. The lactic acid bacteria grew rapidly on the samples, and plate counts around 7.59 log cfu/g and 8.25 log cfu/g were detected after 45 days of storage at 4 °C and 8 °C, respectively; storage temperatures studied showed significant influence on the microorganism in study growth. The predominant lactic acid bacteria associated with the spoilage samples at one day of storage includes Lactobacillus sp., the phenotypic overlap Leuconostoc / Weissella sp. and Enterococcus sp. At 45 days of storage at 4 and 8 °C the mainly specie was Lactobacillus curvatus , following by Lactobacillus sakei and Leuconostoc mesentereoides ; the Enterococcus sp. was not present in the samples.

  3. Characterization of the spoilage lactic acid bacteria in “sliced vacuum-packed cooked ham”

    PubMed Central

    Kalschne, Daneysa Lahis; Womer, Rute; Mattana, Ademir; Sarmento, Cleonice Mendes Pereira; Colla, Luciane Maria; Colla, Eliane

    2015-01-01

    The lactic acid bacteria are involved with food fermentation and in such cases with food spoilage. Considering the need to reduce the lactic acid bacteria growth in meat products, the aim of this work was to enumerated and investigated the lactic acid bacteria present on sliced vacuum-packed cooked ham stored at 4 °C and 8 °C for 45 days by phenotypic and molecular techniques. The quantification showed that the lactic acid bacteria were present from the first day with mean count of 1.98 log cfu/g for the four batches analyzed. The lactic acid bacteria grew rapidly on the samples, and plate counts around 7.59 log cfu/g and 8.25 log cfu/g were detected after 45 days of storage at 4 °C and 8 °C, respectively; storage temperatures studied showed significant influence on the microorganism in study growth. The predominant lactic acid bacteria associated with the spoilage samples at one day of storage includes Lactobacillus sp., the phenotypic overlap Leuconostoc / Weissella sp. and Enterococcus sp. At 45 days of storage at 4 and 8 °C the mainly specie was Lactobacillus curvatus , following by Lactobacillus sakei and Leuconostoc mesentereoides ; the Enterococcus sp. was not present in the samples. PMID:26221105

  4. Lactic acid bacteria: promising supplements for enhancing the biological activities of kombucha.

    PubMed

    Nguyen, Nguyen Khoi; Dong, Ngan Thi Ngoc; Nguyen, Huong Thuy; Le, Phu Hong

    2015-01-01

    Kombucha is sweetened black tea that is fermented by a symbiosis of bacteria and yeast embedded within a cellulose membrane. It is considered a health drink in many countries because it is a rich source of vitamins and may have other health benefits. It has previously been reported that adding lactic acid bacteria (Lactobacillus) strains to kombucha can enhance its biological functions, but in that study only lactic acid bacteria isolated from kefir grains were tested. There are many other natural sources of lactic acid bacteria. In this study, we examined the effects of lactic acid bacteria from various fermented Vietnamese food sources (pickled cabbage, kefir and kombucha) on kombucha's three main biological functions: glucuronic acid production, antibacterial activity and antioxidant ability. Glucuronic acid production was determined by high-performance liquid chromatography-mass spectrometry, antibacterial activity was assessed by the agar-well diffusion method and antioxidant ability was evaluated by determining the 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity. Four strains of food-borne pathogenic bacteria were used in our antibacterial experiments: Listeria monocytogenes ATCC 19111, Escherichia coli ATCC 8739, Salmonella typhimurium ATCC 14028 and Bacillus cereus ATCC 11778. Our findings showed that lactic acid bacteria strains isolated from kefir are superior to those from other sources for improving glucuronic acid production and enhancing the antibacterial and antioxidant activities of kombucha. This study illustrates the potential of Lactobacillus casei and Lactobacillus plantarum isolated from kefir as biosupplements for enhancing the bioactivities of kombucha.

  5. Animal Rennets as Sources of Dairy Lactic Acid Bacteria

    PubMed Central

    Cruciata, Margherita; Sannino, Ciro; Ercolini, Danilo; Scatassa, Maria L.; De Filippis, Francesca; Mancuso, Isabella; La Storia, Antonietta; Moschetti, Giancarlo

    2014-01-01

    The microbial composition of artisan and industrial animal rennet pastes was studied by using both culture-dependent and -independent approaches. Pyrosequencing targeting the 16S rRNA gene allowed to identify 361 operational taxonomic units (OTUs) to the genus/species level. Among lactic acid bacteria (LAB), Streptococcus thermophilus and some lactobacilli, mainly Lactobacillus crispatus and Lactobacillus reuteri, were the most abundant species, with differences among the samples. Twelve groups of microorganisms were targeted by viable plate counts revealing a dominance of mesophilic cocci. All rennets were able to acidify ultrahigh-temperature-processed (UHT) milk as shown by pH and total titratable acidity (TTA). Presumptive LAB isolated at the highest dilutions of acidified milks were phenotypically characterized, grouped, differentiated at the strain level by randomly amplified polymorphic DNA (RAPD)-PCR analysis, and subjected to 16S rRNA gene sequencing. Only 18 strains were clearly identified at the species level, as Enterococcus casseliflavus, Enterococcus faecium, Enterococcus faecalis, Enterococcus lactis, Lactobacillus delbrueckii, and Streptococcus thermophilus, while the other strains, all belonging to the genus Enterococcus, could not be allotted into any previously described species. The phylogenetic analysis showed that these strains might represent different unknown species. All strains were evaluated for their dairy technological performances. All isolates produced diacetyl, and 10 of them produced a rapid pH drop in milk, but only 3 isolates were also autolytic. This work showed that animal rennet pastes can be sources of LAB, mainly enterococci, that might contribute to the microbial diversity associated with dairy productions. PMID:24441167

  6. Animal rennets as sources of dairy lactic acid bacteria.

    PubMed

    Cruciata, Margherita; Sannino, Ciro; Ercolini, Danilo; Scatassa, Maria L; De Filippis, Francesca; Mancuso, Isabella; La Storia, Antonietta; Moschetti, Giancarlo; Settanni, Luca

    2014-04-01

    The microbial composition of artisan and industrial animal rennet pastes was studied by using both culture-dependent and -independent approaches. Pyrosequencing targeting the 16S rRNA gene allowed to identify 361 operational taxonomic units (OTUs) to the genus/species level. Among lactic acid bacteria (LAB), Streptococcus thermophilus and some lactobacilli, mainly Lactobacillus crispatus and Lactobacillus reuteri, were the most abundant species, with differences among the samples. Twelve groups of microorganisms were targeted by viable plate counts revealing a dominance of mesophilic cocci. All rennets were able to acidify ultrahigh-temperature-processed (UHT) milk as shown by pH and total titratable acidity (TTA). Presumptive LAB isolated at the highest dilutions of acidified milks were phenotypically characterized, grouped, differentiated at the strain level by randomly amplified polymorphic DNA (RAPD)-PCR analysis, and subjected to 16S rRNA gene sequencing. Only 18 strains were clearly identified at the species level, as Enterococcus casseliflavus, Enterococcus faecium, Enterococcus faecalis, Enterococcus lactis, Lactobacillus delbrueckii, and Streptococcus thermophilus, while the other strains, all belonging to the genus Enterococcus, could not be allotted into any previously described species. The phylogenetic analysis showed that these strains might represent different unknown species. All strains were evaluated for their dairy technological performances. All isolates produced diacetyl, and 10 of them produced a rapid pH drop in milk, but only 3 isolates were also autolytic. This work showed that animal rennet pastes can be sources of LAB, mainly enterococci, that might contribute to the microbial diversity associated with dairy productions.

  7. Nonstarter lactic acid bacteria volatilomes produced using cheese components.

    PubMed

    Sgarbi, E; Lazzi, C; Tabanelli, G; Gatti, M; Neviani, E; Gardini, F

    2013-07-01

    In long-ripened cheese, flavor formation occurs during ripening. The metabolism of lactic acid bacteria (LAB) leads to the production of different compounds that contribute to the flavor of cheese. The contribution of LAB to the formation of cheese flavor has previously been studied. However, the specific nonstarter LAB (NSLAB) metabolic reactions in ripened cheese that lead to the formation of flavor compounds remain unclear. In ripened cheese, the nutrient sources available include small peptides or amino acids, citrate, lactate, free fatty acids, and starter LAB cell lysis products. Thus, the aim of this study was to evaluate the ability of NSLAB to produce volatile flavor compounds by using an in vitro system that used only the nutrients available in ripened cheese as the energy source. Moreover, the potential contribution of the NSLAB volatilome on total cheese flavor is discussed. For this purpose, the production of volatile compounds on cheese-based medium (CBM) and on starter LAB lysed cell medium (LCM) by 2 Lactobacillus casei and 2 Lactobacillus rhamnosus strains, previously isolated from ripened Parmigiano Reggiano cheese, was investigated. The generated volatile compounds were analyzed with head-space gas chromatography mass spectrometry. Overall, ketones, aldehydes, alcohols, and acids were the most abundant compounds produced. Differences in volatilome production were found between NSLAB grown in LCM and CBM. The catabolic metabolism of amino acids and fatty acids were required for NSLAB growth on LCM. Conversely, pyruvate metabolism was the main catabolic pathway that supported growth of NSLAB in CBM. This study can be considered a first step toward a better understanding of how microbiota involved in the long ripening of cheese may contribute to the development of cheese flavor.

  8. Isolation of lactic acid bacteria with potential protective culture characteristics from fruits

    NASA Astrophysics Data System (ADS)

    Hashim, Nurul Huda; Sani, Norrakiah Abdullah

    2015-09-01

    Lactic acid bacteria are also known as beneficial microorganisms abundantly found in fermented food products. In this study, lactic acid bacteria were isolated from fresh cut fruits obtained from local markets. Throughout the isolation process from 11 samples of fruits, 225 presumptive lactic acid bacteria were isolated on MRS agar medium. After catalase and oxidase tests, 149 resulted to fit the characteristics of lactic acid bacteria. Further identification using Gram staining was conducted to identify the Gram positive bacteria. After this confirmation, the fermentation characteristics of these isolates were identified. It was found that 87 (58.4%) isolates were heterofermentative, while the rest of 62 (41.6%) are homofermentative lactic acid bacteria. Later, all these isolates were investigated for the ability to inhibit growth of Staphylococcus aureus using agar spot assay method. Seven (4.7%) isolates showed strong antagonistic capacity, while 127 (85.2%) and 8 (5.4%) isolates have medium and weak antagonistic capacity, respectively. The other 7 (4.7%) isolates indicated to have no antagonistic effect on S. aureus. Results support the potential of LAB isolated in this study which showed strong antagonistic activity against S. aureus may be manipulated to become protective cultures in food products. While the homofermentative or heterofermentative LAB can be utilized in fermentation of food and non-food products depending on the by-products required during the fermentation.

  9. Probiotic lactic acid bacteria – the fledgling cuckoos of the gut?

    PubMed Central

    Berstad, Arnold; Raa, Jan; Midtvedt, Tore; Valeur, Jørgen

    2016-01-01

    It is tempting to look at bacteria from our human egocentric point of view and label them as either ‘good’ or ‘bad’. However, a microbial society has its own system of government – ‘microcracy’ – and its own rules of play. Lactic acid bacteria are often referred to as representatives of the good ones, and there is little doubt that those belonging to the normal intestinal flora are beneficial for human health. But we should stop thinking of lactic acid bacteria as always being ‘friendly’ – they may instead behave like fledgling cuckoos. PMID:27235098

  10. Capacity of lactic acid bacteria in immunity enhancement and cancer prevention.

    PubMed

    Riaz Rajoka, Muhammad Shahid; Shi, Junling; Zhu, Jing; Shao, Dongyan; Huang, Qingsheng; Yang, Hui; Jin, Mingliang

    2017-01-01

    Lactic acid bacteria are associated with the human gastrointestinal tract. They are important for maintaining the balance of microflora in the human gut. An increasing number of published research reports in recent years have denoted the importance of producing interferon-gamma and IgA for treatment of disease. These agents can enhance the specific and nonspecific immune systems that are dependent on specific bacterial strains. The mechanisms of these effects were revealed in this investigation, where the cell walls of these bacteria were modulated by the cytokine pathways, while the whole bacterial cell mediated the host cell immune system and regulated the production of tumor necrosis factors and interleukins. A supplement of highly active lactic acid bacteria strains provided significant potential to enhance host's immunity, offering prevention from many diseases including some cancers. This review summarizes the current understanding of the function of lactic acid bacteria immunity enhancement and cancer prevention.

  11. Phenotypic and genotypic characterization of lactic acid bacteria isolated from raw goat milk and effect of farming practices on the dominant species of lactic acid bacteria.

    PubMed

    Tormo, Hélène; Ali Haimoud Lekhal, Djamila; Roques, C

    2015-10-01

    Lactic acid bacteria, in particular Lactococcus lactis, play a decisive role in the cheese making process and more particularly in lactic cheeses which are primarily produced on goat dairy farms. The objective of this study was therefore to identify the main lactic acid bacteria found in raw goats' milk from three different regions in France and evaluate if certain farming practices have an effect on the distribution of species of lactic acid bacteria in the various milk samples. Identification at genus or species level was carried out using phenotypic tests and genotypic methods including repetitive element REP-PCR, species-specific PCR and 16S rRNA gene sequencing. The distribution of the main bacterial species in the milk samples varied depending on farms and their characteristics. Out of the 146 strains identified, L. lactis was the dominant species (60% of strains), followed by Enterococcus (38%) of which Enterococcus faecalis and Enterococcus faecium. Within the species L. lactis, L. lactis subsp lactis was detected more frequently than L. lactis subsp cremoris (74% vs. 26%). The predominance of L. lactis subsp cremoris was linked to geographical area studied. It appears that the animals' environment plays a role in the balance between the dominance of L. lactis and enterococci in raw goats' milk. The separation between the milking parlor and the goat shed (vs no separation) and only straw in the bedding (vs straw and hay) seems to promote L. lactis in the milk (vs enterococci).

  12. Spoilage and safety characteristics of ground beef treated with lactic acid bacteria.

    PubMed

    Hoyle, A R; Brooks, J C; Thompson, L D; Palmore, W; Stephens, T P; Brashears, M M

    2009-11-01

    Lactic acid bacteria (LAB) can decrease numbers of Escherichia coli O157:H7 and Salmonella in ground beef during storage. Two dose-titration studies were conducted in ground beef to determine dose levels of LAB needed to inhibit the pathogens. A second study evaluated whether LAB masked changes typically associated with the spoilage of ground beef displayed under refrigerated (0 degrees C) or abusive (10 degrees C) temperatures packaged in both traditional overwrap (TOP) and modified atmosphere packaging (MAP; 80% O(2)-20% CO(2)). Microbial analyses were conducted to determine spoilage endpoints and pathogen reduction. In the dose-titration study, Salmonella was reduced by 3 log cycles at all doses (10(6), 10(7), and 10(8) LAB per g) after 3 days of storage and was eliminated after 5 days of storage. E. coli O157:H7 was reduced by 2 log cycles at all dosages after 3 days of storage and by 3 log cycles after 5 days of storage. In the spoilage studies, as expected, total aerobic plate counts and LAB populations in LAB-inoculated samples were higher than the controls initially, but the counts were similar near the end of the study. While total spoilage bacteria generally increased over time, very few differences existed between treatments stored at 0 degrees C and 10 degrees C in coliforms, Brochothrix thermosphacta, yeasts and molds, and Pseudomonas spp. counts for both the TOP and MAP samples. We conclude that LAB could potentially be added to ground beef in TOP and MAP as a processing intervention for E. coli O157:H7 and Salmonella without masking microbial spoilage characteristics.

  13. Purification Techniques of Bacteriocins from Lactic Acid Bacteria and Other Gram-Positive Bacteria

    NASA Astrophysics Data System (ADS)

    Saavedra, Lucila; Sesma, Fernando

    The search for new antimicrobial peptides produced by lactic acid ­bacteria and other Gram-positive microorganisms has become an interesting field of research in the past decades. The fact that bacteriocins are active against numerous foodborne and human pathogens, are produced by generally regarded as safe (GRAS) microorganisms, and are readily degraded by proteolytic host systems makes them attractive candidates for biotechnological applications. However, before suggesting or choosing a new bacteriocin for future technology developments, it is necessary to elucidate its biochemical structure and its mode of action, which may be carried out once the bacteriocin is purified to homogeneity. This chapter focuses on describing the main strategies used for the purification of numerous bacteriocins.

  14. Isolation of alkaliphilic bacteria for production of high optically pure L-(+)-lactic acid.

    PubMed

    Yokaryo, Hiroto; Tokiwa, Yutaka

    2014-01-01

    Lactic acid bacteria that grow under alkaline conditions (pH 10) were isolated from various sources in Okinawa (Japan). These alkali-tolerant and alkaliphilic bacteria were classified as follows: Microbacterium sp. (1 strain), Enterococcus spp. (9 strains), Alkalibacterium spp. (3 strains), Exiguobacterium spp. (5 strains), Oceanobacillus spp. (3 strains) and Bacillus spp. (7 strains) by 16S rRNA gene sequencing. By fermentation, many strains were able to convert glucose into mainly L-(+)-lactic acid of high optical purity in alkaline broth. This result indicated that valuable L-(+)-lactic acid-producing bacteria could be isolated efficiently by screening under alkaline conditions. Six strains were selected and their ability to produce lactic acid at different initial pH was compared. Enterococcus casseliflavus strain 79w3 gave the highest lactic acid concentration. Lactic acid concentration and productivity were 103 g L(-1) (optical purity of 99.5% as L-isomer) and 2.2 g L(-1) h(-1), respectively when 129 g L(-1) of glucose was used by batch fermentation.

  15. Plasmids from Food Lactic Acid Bacteria: Diversity, Similarity, and New Developments.

    PubMed

    Cui, Yanhua; Hu, Tong; Qu, Xiaojun; Zhang, Lanwei; Ding, Zhongqing; Dong, Aijun

    2015-06-10

    Plasmids are widely distributed in different sources of lactic acid bacteria (LAB) as self-replicating extrachromosomal genetic materials, and have received considerable attention due to their close relationship with many important functions as well as some industrially relevant characteristics of the LAB species. They are interesting with regard to the development of food-grade cloning vectors. This review summarizes new developments in the area of lactic acid bacteria plasmids and aims to provide up to date information that can be used in related future research.

  16. Plasmids from Food Lactic Acid Bacteria: Diversity, Similarity, and New Developments

    PubMed Central

    Cui, Yanhua; Hu, Tong; Qu, Xiaojun; Zhang, Lanwei; Ding, Zhongqing; Dong, Aijun

    2015-01-01

    Plasmids are widely distributed in different sources of lactic acid bacteria (LAB) as self-replicating extrachromosomal genetic materials, and have received considerable attention due to their close relationship with many important functions as well as some industrially relevant characteristics of the LAB species. They are interesting with regard to the development of food-grade cloning vectors. This review summarizes new developments in the area of lactic acid bacteria plasmids and aims to provide up to date information that can be used in related future research. PMID:26068451

  17. Evaluation of the petrifilm aerobic count plate for enumeration of aerobic marine bacteria from seawater and Caulerpa lentillifera.

    PubMed

    Kudaka, Jun; Horii, Toru; Tamanaha, Koji; Itokazu, Kiyomasa; Nakamura, Masaji; Taira, Katsuya; Nidaira, Minoru; Okano, Sho; Kitahara, Akio

    2010-08-01

    The enumeration and evaluation of the activity of marine bacteria are important in the food industry. However, detection of marine bacteria in seawater or seafood has not been easy. The Petrifilm aerobic count plate (ACP) is a ready-to-use alternative to the traditional enumeration media used for bacteria associated with food. The purpose of this study was to evaluate the usefulness of a simple detection and enumeration method utilizing the Petrifilm ACP for enumeration of aerobic marine bacteria from seawater and an edible seaweed, Caulerpa lentillifera. The efficiency of enumeration of total aerobic marine bacteria on Petrifilm ACP was compared with that using the spread plate method on marine agar with 80 seawater and 64 C. lentillifera samples. With sterile seawater as the diluent, a close correlation was observed between the method utilizing Petrifilm ACP and that utilizing the conventional marine agar (r=0.98 for seawater and 0.91 for C. lentillifera). The Petrifilm ACP method was simpler and less time-consuming than the conventional method. These results indicate that Petrifilm ACP is a suitable alternative to conventional marine agar for enumeration of marine microorganisms in seawater and C. lentillifera samples.

  18. The importance of lactic acid bacteria for phytate degradation during cereal dough fermentation.

    PubMed

    Reale, Anna; Konietzny, Ursula; Coppola, Raffaele; Sorrentino, Elena; Greiner, Ralf

    2007-04-18

    Lactic acid fermentation of cereal flours resulted in a 100 (rye), 95-100 (wheat), and 39-47% (oat) reduction in phytate content within 24 h. The extent of phytate degradation was shown to be independent from the lactic acid bacteria strain used for fermentation. However, phytate degradation during cereal dough fermentation was positively correlated with endogenous plant phytase activity (rye, 6750 mU g(-1); wheat, 2930 mU g(-1); and oat, 23 mU g(-1)), and heat inactivation of the endogenous cereal phytases prior to lactic acid fermentation resulted in a complete loss of phytate degradation. Phytate degradation was restored after addition of a purified phytase to the liquid dough. Incubation of the cereal flours in buffered solutions resulted in a pH-dependent phytate degradation. The optimum of phytate degradation was shown to be around pH 5.5. Studies on phytase production of 50 lactic acid bacteria strains, previously isolated from sourdoughs, did not result in a significant production of intra- as well as extracellular phytase activity. Therefore, lactic acid bacteria do not participate directly in phytate degradation but provide favorable conditions for the endogenous cereal phytase activity by lowering the pH value.

  19. Glucansucrases from lactic acid bacteria which produce water-insoluble polysaccharides from sucrose

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dextrans and related glucans produced from sucrose by lactic acid bacteria have been studied for many years and are used in numerous commercial applications and products. Most of these glucans are water-soluble, except for a few notable exceptions from cariogenic Streptococcus spp. and a very small ...

  20. Drivers for the establishment and composition of the sourdough lactic acid bacteria biota.

    PubMed

    Gobbetti, Marco; Minervini, Fabio; Pontonio, Erica; Di Cagno, Raffaella; De Angelis, Maria

    2016-12-19

    The drivers for the establishment and composition of the sourdough microbiota, with particular emphasis on lactic acid bacteria, are reviewed and discussed. More than 60 different species of lactobacilli were identified from sourdoughs, showing the main overlapping between sourdough and human intestine ecosystems. The microbial kinetics during sourdough preparation was described by several studies using various methodological approaches, including culture-dependent and -independent (e.g., high throughput sequencing), and metabolite and meta-transcriptome analyses. Although the abundant microbial diversity harbored by flours, a succession of dominating and sub-dominating populations of lactic acid bacteria suddenly occurred during sourdough propagation, leading to the progressive assembly of the bacterial community. The contribution of all the potential sources (house microbiota, flour, types of flours and additional ingredients) for contaminating lactic acid bacteria was compared with the aim to find overlapping or specific routes that affect the sourdough microbiota. Once established and mature, pros and cons regarding the stability of the sourdough lactic acid bacteria biota were also reviewed, showing contradictory results, which were mainly dependent on the species/strains. Probably, the future research efforts should be dedicated to decrease the sources/drivers of noticeable variation rather than to full standardization of the process for sourdough preparation and use.

  1. Multiple Genome Sequences of Important Beer-Spoiling Lactic Acid Bacteria

    PubMed Central

    Geissler, Andreas J.; Vogel, Rudi F.

    2016-01-01

    Seven strains of important beer-spoiling lactic acid bacteria were sequenced using single-molecule real-time sequencing. Complete genomes were obtained for strains of Lactobacillus paracollinoides, Lactobacillus lindneri, and Pediococcus claussenii. The analysis of these genomes emphasizes the role of plasmids as the genomic foundation of beer-spoiling ability. PMID:27795248

  2. Survival and growth of probiotic lactic acid bacteria in refrigerated pickle products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined 10 lactic acid bacteria that have been previously characterized for commercial use as probiotic cultures, mostly for dairy products, including 1 Pediococcus and 9 Lactobacilli. Our objectives were to develop a rapid procedure for determining the long-term survivability of these cultures ...

  3. Bacteriophages of lactic acid bacteria and their impact on milk fermentations

    PubMed Central

    2011-01-01

    Every biotechnology process that relies on the use of bacteria to make a product or to overproduce a molecule may, at some time, struggle with the presence of virulent phages. For example, phages are the primary cause of fermentation failure in the milk transformation industry. This review focuses on the recent scientific advances in the field of lactic acid bacteria phage research. Three specific topics, namely, the sources of contamination, the detection methods and the control procedures will be discussed. PMID:21995802

  4. Lactic acid bacteria in the quality improvement and depreciation of wine.

    PubMed

    Lonvaud-Funel, A

    1999-01-01

    The winemaking process includes two main steps: lactic acid bacteria are responsible for the malolactic fermentation which follows the alcoholic fermentation by yeasts. Both types of microorganisms are present on grapes and on cellar equipment. Yeasts are better adapted to growth in grape must than lactic acid bacteria, so the alcoholic fermentation starts quickly. In must, up to ten lactic acid bacteria species can be identified. They belong to the Lactobacillus, Pediococcus, Leuconostoc and Oenococcus genera. Throughout alcoholic fermentation, a natural selection occurs and finally the dominant species is O. oeni, due to interactions between yeasts and bacteria and between bacteria themselves. After bacterial growth, when the population is over 10(6) CFU/ml, malolactic transformation is the obvious change in wine composition. However, many other substrates can be metabolized. Some like remaining sugars and citric acid are always assimilated by lactic acid bacteria, thus providing them with energy and carbon. Other substrates such as some amino acids may be used following pathways restricted to strains carrying the adequate enzymes. Some strains can also produce exopolysaccharides. All these transformations greatly influence the sensory and hygienic quality of wine. Malic acid transformation is encouraged because it induces deacidification. Diacetyl produced from citric acid is also helpful to some extent. Sensory analyses show that many other reactions change the aromas and make malolactic fermentation beneficial, but they are as yet unknown. On the contrary, an excess of acetic acid, the synthesis of glucane, biogenic amines and precursors of ethylcarbamate are undesirable. Fortunately, lactic acid bacteria normally multiply in dry wines; moreover some of these activities are not widespread. Moreover, the most striking trait of wine lactic acid bacteria is their capacity to adapt to a hostile environment. The mechanisms for this are not yet completely elucidated

  5. Isolation and characterization of bacteriocinogenic lactic bacteria from M-Tuba and Tepache, two traditional fermented beverages in México.

    PubMed

    de la Fuente-Salcido, Norma M; Castañeda-Ramírez, José Cristobal; García-Almendárez, Blanca E; Bideshi, Dennis K; Salcedo-Hernández, Rubén; Barboza-Corona, José E

    2015-09-01

    Mexican Tuba (M-Tuba) and Tepache are Mexican fermented beverages prepared mainly with pineapple pulp and coconut palm, respectively. At present, reports on the microbiota and nutritional effects of both beverages are lacking. The purpose of this study was to determine whether M-Tuba and Tepache contain cultivable lactic acid bacteria (LAB) capable of producing bacteriocins. Tepache and M-Tuba contain mesophilic aerobic bacteria, LAB, and yeast. Bacillus subtilis, Listeria monocytogenes, Listeria innocua, Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium, and Salmonella spp, were the microorganisms most susceptible to metabolites produced by bacterial isolates. M-Tuba and Tepache contain bacteria that harbor genes coding for nisin and enterocin, but not pediocin. The presence of Lactococcus lactis and E. faecium in M-Tuba and Tepache, was identified by 16S rDNA. These bacteria produced bacteriocins of ∼3.5 kDa and 4.0-4.5 kDa, respectively. Partial purified bacteriocins showed inhibitory effect against Micrococcus luteus, L. monocytogenes, L. innocua, Str. agalactiae, S. aureus, Bacillus cereus, B. subtilis, E. faecalis, and K. pneumoniae. We characterized, for the first time, cultivable microbiota of M-Tuba and Tepache, and specifically, identified candidate lactic bacteria (LAB) present in these beverages that were capable of synthesizing antimicrobial peptides, which collectively could provide food preservative functions.

  6. Isolation and characterization of bacteriocinogenic lactic bacteria from M-Tuba and Tepache, two traditional fermented beverages in México

    PubMed Central

    de la Fuente-Salcido, Norma M; Castañeda-Ramírez, José Cristobal; García-Almendárez, Blanca E; Bideshi, Dennis K; Salcedo-Hernández, Rubén; Barboza-Corona, José E

    2015-01-01

    Mexican Tuba (M-Tuba) and Tepache are Mexican fermented beverages prepared mainly with pineapple pulp and coconut palm, respectively. At present, reports on the microbiota and nutritional effects of both beverages are lacking. The purpose of this study was to determine whether M-Tuba and Tepache contain cultivable lactic acid bacteria (LAB) capable of producing bacteriocins. Tepache and M-Tuba contain mesophilic aerobic bacteria, LAB, and yeast. Bacillus subtilis, Listeria monocytogenes, Listeria innocua, Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium, and Salmonella spp, were the microorganisms most susceptible to metabolites produced by bacterial isolates. M-Tuba and Tepache contain bacteria that harbor genes coding for nisin and enterocin, but not pediocin. The presence of Lactococcus lactis and E. faecium in M-Tuba and Tepache, was identified by 16S rDNA. These bacteria produced bacteriocins of ∼3.5 kDa and 4.0–4.5 kDa, respectively. Partial purified bacteriocins showed inhibitory effect against Micrococcus luteus, L. monocytogenes, L. innocua, Str. agalactiae, S. aureus, Bacillus cereus, B. subtilis, E. faecalis, and K. pneumoniae. We characterized, for the first time, cultivable microbiota of M-Tuba and Tepache, and specifically, identified candidate lactic bacteria (LAB) present in these beverages that were capable of synthesizing antimicrobial peptides, which collectively could provide food preservative functions. PMID:26405529

  7. Lactic acid bacteria in dairy food: surface characterization and interactions with food matrix components.

    PubMed

    Burgain, J; Scher, J; Francius, G; Borges, F; Corgneau, M; Revol-Junelles, A M; Cailliez-Grimal, C; Gaiani, C

    2014-11-01

    This review gives an overview of the importance of interactions occurring in dairy matrices between Lactic Acid Bacteria and milk components. Dairy products are important sources of biological active compounds of particular relevance to human health. These compounds include immunoglobulins, whey proteins and peptides, polar lipids, and lactic acid bacteria including probiotics. A better understanding of interactions between bioactive components and their delivery matrix may successfully improve their transport to their target site of action. Pioneering research on probiotic lactic acid bacteria has mainly focused on their host effects. However, very little is known about their interaction with dairy ingredients. Such knowledge could contribute to designing new and more efficient dairy food, and to better understand relationships between milk constituents. The purpose of this review is first to provide an overview of the current knowledge about the biomolecules produced on bacterial surface and the composition of the dairy matter. In order to understand how bacteria interact with dairy molecules, adhesion mechanisms are subsequently reviewed with a special focus on the environmental conditions affecting bacterial adhesion. Methods dedicated to investigate the bacterial surface and to decipher interactions between bacteria and abiotic dairy components are also detailed. Finally, relevant industrial implications of these interactions are presented and discussed.

  8. Isolation, characterization and evaluation of probiotic lactic acid bacteria for potential use in animal production.

    PubMed

    García-Hernández, Yaneisy; Pérez-Sánchez, Tania; Boucourt, Ramón; Balcázar, José L; Nicoli, Jacques R; Moreira-Silva, João; Rodríguez, Zoraya; Fuertes, Héctor; Nuñez, Odalys; Albelo, Nereyda; Halaihel, Nabil

    2016-10-01

    In livestock production, lactic acid bacteria (LAB) are the most common microorganisms used as probiotics. For such use, these bacteria must be correctly identified and characterized to ensure their safety and efficiency. In the present study, LAB were isolated from broiler excreta, where a fermentation process was used. Nine among sixteen isolates were identified by biochemical and molecular (sequencing of the 16S rRNA gene) methods as Lactobacillus crispatus (n=1), Lactobacillus pentosus (n=1), Weissella cibaria (n=1), Pediococcus pentosaceus (n=2) and Enterococcus hirae (n=4). Subsequently, these bacteria were characterized for their growth capabilities, lactic acid production, acidic pH and bile salts tolerance, cell surface hydrophobicity, antimicrobial susceptibility and antagonistic activity. Lactobacillus pentosus strain LB-31, which showed the best characteristics, was selected for further analysis. This strain was administered to broilers and showed the ability of modulating the immune response and producing beneficial effects on morpho-physiological, productive and health indicators of the animals.

  9. Structural diversity and biological significance of lipoteichoic acid in Gram-positive bacteria: focusing on beneficial probiotic lactic acid bacteria.

    PubMed

    Shiraishi, Tsukasa; Yokota, Shinichi; Fukiya, Satoru; Yokota, Atsushi

    2016-01-01

    Bacterial cell surface molecules are at the forefront of host-bacterium interactions. Teichoic acids are observed only in Gram-positive bacteria, and they are one of the main cell surface components. Teichoic acids play important physiological roles and contribute to the bacterial interaction with their host. In particular, lipoteichoic acid (LTA) anchored to the cell membrane has attracted attention as a host immunomodulator. Chemical and biological characteristics of LTA from various bacteria have been described. However, most of the information concerns pathogenic bacteria, and information on beneficial bacteria, including probiotic lactic acid bacteria, is insufficient. LTA is structurally diverse. Strain-level structural diversity of LTA is suggested to underpin its immunomodulatory activities. Thus, the structural information on LTA in probiotics, in particular strain-associated diversity, is important for understanding its beneficial roles associated with the modulation of immune response. Continued accumulation of structural information is necessary to elucidate the detailed physiological roles and significance of LTA. In this review article, we summarize the current state of knowledge on LTA structure, in particular the structure of LTA from lactic acid bacteria. We also describe the significance of structural diversity and biological roles of LTA.

  10. Structural diversity and biological significance of lipoteichoic acid in Gram-positive bacteria: focusing on beneficial probiotic lactic acid bacteria

    PubMed Central

    SHIRAISHI, Tsukasa; YOKOTA, Shinichi; FUKIYA, Satoru; YOKOTA, Atsushi

    2016-01-01

    Bacterial cell surface molecules are at the forefront of host-bacterium interactions. Teichoic acids are observed only in Gram-positive bacteria, and they are one of the main cell surface components. Teichoic acids play important physiological roles and contribute to the bacterial interaction with their host. In particular, lipoteichoic acid (LTA) anchored to the cell membrane has attracted attention as a host immunomodulator. Chemical and biological characteristics of LTA from various bacteria have been described. However, most of the information concerns pathogenic bacteria, and information on beneficial bacteria, including probiotic lactic acid bacteria, is insufficient. LTA is structurally diverse. Strain-level structural diversity of LTA is suggested to underpin its immunomodulatory activities. Thus, the structural information on LTA in probiotics, in particular strain-associated diversity, is important for understanding its beneficial roles associated with the modulation of immune response. Continued accumulation of structural information is necessary to elucidate the detailed physiological roles and significance of LTA. In this review article, we summarize the current state of knowledge on LTA structure, in particular the structure of LTA from lactic acid bacteria. We also describe the significance of structural diversity and biological roles of LTA. PMID:27867802

  11. Antibiotic Susceptibility Pattern of Aerobic and Anaerobic Bacteria Isolated From Surgical Site Infection of Hospitalized Patients

    PubMed Central

    Akhi, Mohammad Taghi; Ghotaslou, Reza; Beheshtirouy, Samad; Asgharzadeh, Mohammad; Pirzadeh, Tahereh; Asghari, Babak; Alizadeh, Naser; Toloue Ostadgavahi, Ali; Sorayaei Somesaraei, Vida; Memar, Mohammad Yousef

    2015-01-01

    Background: Surgical Site Infections (SSIs) are infections of incision or deep tissue at operation sites. These infections prolong hospitalization, delay wound healing, and increase the overall cost and morbidity. Objectives: This study aimed to investigate anaerobic and aerobic bacteria prevalence in surgical site infections and determinate antibiotic susceptibility pattern in these isolates. Materials and Methods: One hundred SSIs specimens were obtained by needle aspiration from purulent material in depth of infected site. These specimens were cultured and incubated in both aerobic and anaerobic condition. For detection of antibiotic susceptibility pattern in aerobic and anaerobic bacteria, we used disk diffusion, agar dilution, and E-test methods. Results: A total of 194 bacterial strains were isolated from 100 samples of surgical sites. Predominant aerobic and facultative anaerobic bacteria isolated from these specimens were the members of Enterobacteriaceae family (66, 34.03%) followed by Pseudomonas aeruginosa (26, 13.4%), Staphylococcus aureus (24, 12.37%), Acinetobacter spp. (18, 9.28%), Enterococcus spp. (16, 8.24%), coagulase negative Staphylococcus spp. (14, 7.22%) and nonhemolytic streptococci (2, 1.03%). Bacteroides fragilis (26, 13.4%), and Clostridium perfringens (2, 1.03%) were isolated as anaerobic bacteria. The most resistant bacteria among anaerobic isolates were B. fragilis. All Gram-positive isolates were susceptible to vancomycin and linezolid while most of Enterobacteriaceae showed sensitivity to imipenem. Conclusions: Most SSIs specimens were polymicrobial and predominant anaerobic isolate was B. fragilis. Isolated aerobic and anaerobic strains showed high level of resistance to antibiotics. PMID:26421133

  12. Interactions among lactic acid starter and probiotic bacteria used for fermented dairy products.

    PubMed

    Vinderola, C G; Mocchiutti, P; Reinheimer, J A

    2002-04-01

    Interactions among lactic acid starter and probiotic bacteria were investigated to establish adequate combinations of strains to manufacture probiotic dairy products. For this aim, a total of 48 strains of Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactococcus lactis, Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium spp. (eight of each) were used. The detection of bacterial interactions was carried out using the well-diffusion agar assay, and the interactions found were further characterized by growth kinetics. A variety of interactions was demonstrated. Lb. delbrueckii subsp. bulgaricus was found to be able to inhibit S. thermophilus strains. Among probiotic cultures, Lb. acidophilus was the sole species that was inhibited by the others (Lb. casei and Bifidobacterium). In general, probiotic bacteria proved to be more inhibitory towards lactic acid bacteria than vice versa since the latter did not exert any effect on the growth of the former, with some exceptions. The study of interactions by growth kinetics allowed the setting of four different kinds of behaviors between species of lactic acid starter and probiotic bacteria (stimulation, delay, complete inhibition of growth, and no effects among them). The possible interactions among the strains selected to manufacture a probiotic fermented dairy product should be taken into account when choosing the best combination/s to optimize their performance in the process and their survival in the products during cold storage.

  13. Coevolution with bacteria drives the evolution of aerobic fermentation in Lachancea kluyveri

    PubMed Central

    McDonald, Michael J.; Galafassi, Silvia; Compagno, Concetta; Piškur, Jure

    2017-01-01

    The Crabtree positive yeasts, such as Saccharomyces cerevisiae, prefer fermentation to respiration, even under fully aerobic conditions. The selective pressures that drove the evolution of this trait remain controversial because of the low ATP yield of fermentation compared to respiration. Here we propagate experimental populations of the weak-Crabtree yeast Lachancea kluyveri, in competitive co-culture with bacteria. We find that L. kluyveri adapts by producing quantities of ethanol lethal to bacteria and evolves several of the defining characteristics of Crabtree positive yeasts. We use precise quantitative analysis to show that the rate advantage of fermentation over aerobic respiration is insufficient to provide an overall growth advantage. Thus, the rapid consumption of glucose and the utilization of ethanol are essential for the success of the aerobic fermentation strategy. These results corroborate that selection derived from competition with bacteria could have provided the impetus for the evolution of the Crabtree positive trait. PMID:28282411

  14. Abundance and salt tolerance of obligately aerobic, phototrophic bacteria in a marine microbial mat

    NASA Astrophysics Data System (ADS)

    Yurkov, Vladimir V.; Van Gemerden, Hans

    Data have been collected on the abundance of obligately aerobic, bacteriochlorophyll- a-containing bacteria in a marine microbial mat on the West Frisian Island of Texel, The Netherlands. Plate counts on media rich in organic matter revealed average numbers of 3 ∗10 5·cm -3 sediment in the top 10 mm of the mat; the number of purple non-sulphur bacteria was of the same magnitude. Due to the relatively small dimensions of obligately aerobic anoxygenic phototrophic bacteria and purple non-sulphur bacteria, compared to those of purple sulphur bacteria, the contributions of either of the two former groups to the biomass of Bchl- a-containing organisms was approximately 3%. The specific Bchl- a-content of the isolated obligately aerobic phototrophs was very low (0.8 to 1.0 μg·mg -1 protein) compared to that of purple non-sulphur bacteria (16 to 20 μg·mg -1 protein), and purple sulphur bacteria (27 to 30 μg·mg -1). As a consequence, the relative contribution to the total Bchl a concentration of the two former groups (0.1% and 2.1%, respectively) was negligible, compared to that of the purple sulphur bacteria (97.8%). Salinities <50 had little effect on growth rate and yield of isolates; at salinities between 50 and 100 the doubling time increased progressively with a concomitant decrease in yield; no growth occurred at salinities > 140.

  15. Key volatile aroma compounds of lactic acid fermented malt based beverages - impact of lactic acid bacteria strains.

    PubMed

    Nsogning Dongmo, Sorelle; Sacher, Bertram; Kollmannsberger, Hubert; Becker, Thomas

    2017-08-15

    This study aims to define the aroma composition and key aroma compounds of barley malt wort beverages produced from fermentation using six lactic acid bacteria (LAB) strains. Gas chromatography mass spectrometry-olfactometry and flame ionization detection was employed; key aroma compounds were determined by means of aroma extract dilution analysis. Fifty-six detected volatile compounds were similar among beverages. However, significant differences were observed in the concentration of individual compounds. Key aroma compounds (flavor dilution (FD) factors ≥16) were β-damascenone, furaneol, phenylacetic acid, 2-phenylethanol, 4-vinylguaiacol, sotolon, methional, vanillin, acetic acid, nor-furaneol, guaiacol and ethyl 2-methylbutanoate. Furthermore, acetaldehyde had the greatest odor activity value of up to 4266. Sensory analyses revealed large differences in the flavor profile. Beverage from L. plantarum Lp. 758 showed the highest FD factors in key aroma compounds and was correlated to fruity flavors. Therefore, we suggest that suitable LAB strain selection may improve the flavor of malt based beverages.

  16. Identification and Characteristics of Lactic Acid Bacteria Isolated from Sour Dough Sponges.

    PubMed

    Okada, S; Ishikawa, M; Yoshida, I; Uchimura, T; Ohara, N; Kozaki, M

    1992-01-01

    Lactic acid bacteria in four samples of sour dough sponges were studied quantitatively and qualitatively. In each sponge, there were one or two species of the genus Lactobacillus: L. reuteri and L. curvatus in San Francisco sour dough sponge, L. brevis and L. hilgardii in panettone sour dough sponge produced in Italy, L. sanfrancisco from a rye sour dough sponge produced in Germany, and L. casei and L. curvatus from a rye sour dough sponge produced in Switzerland. For all isolates except the L. reuteri strains oleic acid, a component of the Tween 80 added to the medium, was essential for growth. It was of interest that lactobacilli requiring oleic acid were the predominant flora of lactic acid bacteria in the microbial environment of sour dough sponges.

  17. Phenolic Biotransformations during Conversion of Ferulic Acid to Vanillin by Lactic Acid Bacteria

    PubMed Central

    Kaur, Baljinder; Kumar, Balvir

    2013-01-01

    Vanillin is widely used as food additive and as a masking agent in various pharmaceutical formulations. Ferulic acid is an important precursor of vanillin that is available in abundance in cell walls of cereals like wheat, corn, and rice. Phenolic biotransformations can occur during growth of lactic acid bacteria (LAB), and their production can be made feasible using specialized LAB strains that have been reported to produce ferulic acid esterases. The present study aimed at screening a panel of LAB isolates for their ability to release phenolics from agrowaste materials like rice bran and their biotransformation to industrially important compounds such as ferulic acid, 4-ethyl phenol, vanillic acid, vanillin, and vanillyl alcohol. Bacterial isolates were evaluated using ferulic acid esterase, ferulic acid decarboxylase, and vanillin dehydrogenase assays. This work highlights the importance of lactic acid bacteria in phenolic biotransformations for the development of food grade flavours and additives. PMID:24066293

  18. Effects of morphological changes in beer-spoilage lactic acid bacteria on membrane filtration in breweries.

    PubMed

    Asano, Shizuka; Suzuki, Koji; Iijima, Kazumaru; Motoyama, Yasuo; Kuriyama, Hidetoshi; Kitagawa, Yasushi

    2007-10-01

    Membrane filter performance was investigated using beer-spoilage lactic acid bacteria (LAB). As a result, beer-adapted LAB strains showed considerably increased penetration rate through filters, as compared with non-adapted strains. Further statistical analyses demonstrated the significant shifts in cell size distribution towards shorter rods, when Lactobacillus brevis and L. lindneri strains were precultured in beer. These results indicate that diminished cell size is responsible for the deteriorated filter performance and, therefore, beer-adapted lactic acid bacteria are regarded as a serious threat to the production of unpasteurized beers. In addition, the selection of test strains and preculture conditions are suggested to be important for the rigorous and standardized evaluation of membrane filter performance in the brewing industry.

  19. Effect of oxidoreduction potential on aroma biosynthesis by lactic acid bacteria in nonfat yogurt.

    PubMed

    Martin, F; Cachon, R; Pernin, K; De Coninck, J; Gervais, P; Guichard, E; Cayot, N

    2011-02-01

    The aim of this study was to investigate the effect of oxidoreduction potential (Eh) on the biosynthesis of aroma compounds by lactic acid bacteria in non-fat yogurt. The study was done with yogurts fermented by Lactobacillus bulgaricus and Streptococcus thermophilus. The Eh was modified by the application of different gaseous conditions (air, nitrogen, and nitrogen/hydrogen). Acetaldehyde, dimethyl sulfide, diacetyl, and pentane-2,3-dione, as the major endogenous odorant compounds of yogurt, were chosen as tracers for the biosynthesis of aroma compounds by lactic acid bacteria. Oxidative conditions favored the production of acetaldehyde, dimethyl sulfide, and diketones (diacetyl and pentane-2,3-dione). The Eh of the medium influences aroma production in yogurt by modifying the metabolic pathways of Lb. bulgaricus and Strep. thermophilus. The use of Eh as a control parameter during yogurt production could permit the control of aroma formation.

  20. [Volatile oil of Anethum Graveolens L. as an inhibitor of yeast and lactic acid bacteria].

    PubMed

    Shcherbanovsky, L R; Kapelev, I G

    1975-01-01

    The antimicrobial activity of 25 volatile oils from aerial parts and seeds of dill (Anethum graveolens L.) of different geographical origin towards yeast Saccharomyces vini and lactic acid bacteria Lactobacterium buchneri was measured by serial dilutions. Volatile oils from mature seeds and green parts of the plants harvested at late vegetation phases showed the highest activity. The geographical origin of plants influenced insignificantly the antimicrobial activity of volatile oil.

  1. Natural lactic acid bacteria population of tropical grasses and their fermentation factor analysis of silage prepared with cellulase and inoculant.

    PubMed

    Khota, Waroon; Pholsen, Suradej; Higgs, David; Cai, Yimin

    2016-12-01

    Natural lactic acid bacteria (LAB) populations in tropical grasses and their fermentation characteristics on silage prepared with cellulase enzyme and LAB inoculants were studied. A commercial inoculant Lactobacillus plantarum Chikuso 1 (CH), a local selected strain Lactobacillus casei TH14 (TH14), and 2 cellulases, Acremonium cellulase (AC) and Maicelase (MC; Meiji Seika Pharma Co. Ltd., Tokyo, Japan), were used as additives to silage preparation with fresh and wilted (6 h) Guinea grass and Napier grass. Silage was prepared using a laboratory-scale fermentation system. Treatments were CH, TH14, AC at 0.01% fresh matter, AC 0.1%, MC 0.01%, MC 0.1%, CH+AC 0.01%, CH+AC 0.1%, CH+MC 0.01%, CH+MC 0.1%, TH14+AC 0.1%, TH14+AC 0.01%, TH14+MC 0.1%, and TH14+MC 0.01%. Microorganism counts of Guinea grass and Napier grass before ensiling were 10(2) LAB and 10(6) aerobic bacteria; these increased during wilting. Based on morphological and biochemical characteristics, and 16S rRNA gene sequence analysis, natural strains from both grasses were identified as L. plantarum, L. casei, Lactobacillus acidipiscis, Leuconostoc pseudomesenteroides, Leuconostoc garlicum, Weissella confusa, and Lactococcus lactis. Lactobacillus plantarum and L. casei are the dominant species and could grow at lower pH and produce more lactic acid than the other isolates. Crude protein and neutral detergent fiber were 5.8 and 83.7% of dry matter (DM) for Guinea grass, and 7.5 and 77.1% of DM for Napier grass. Guinea grass had a low level of water-soluble carbohydrates (0.39% of DM). Guinea grass silage treated with cellulase had a lower pH and higher lactic acid content than control and LAB treatments. The 0.1% AC and MC treatments had the best result for fermentation quality. All high water-soluble carbohydrate (2.38% DM) Napier grass silages showed good fermentation quality. Compared with control and LAB-inoculated silage, the cellulase-treated silages had significantly higher crude protein content and

  2. Occurrence of Arginine Deiminase Pathway Enzymes in Arginine Catabolism by Wine Lactic Acid Bacteria

    PubMed Central

    Liu, S.; Pritchard, G. G.; Hardman, M. J.; Pilone, G. J.

    1995-01-01

    l-Arginine, an amino acid found in significant quantities in grape juice and wine, is known to be catabolized by some wine lactic acid bacteria. The correlation between the occurrence of arginine deiminase pathway enzymes and the ability to catabolize arginine was examined in this study. The activities of the three arginine deiminase pathway enzymes, arginine deiminase, ornithine transcarbamylase, and carbamate kinase, were measured in cell extracts of 35 strains of wine lactic acid bacteria. These enzymes were present in all heterofermentative lactobacilli and most leuconostocs but were absent in all the homofermentative lactobacilli and pediococci examined. There was a good correlation among arginine degradation, formation of ammonia and citrulline, and the occurrence of arginine deiminase pathway enzymes. Urea was not detected during arginine degradation, suggesting that the catabolism of arginine did not proceed via the arginase-catalyzed reaction, as has been suggested in some earlier studies. Detection of ammonia with Nessler's reagent was shown to be a simple, rapid test to assess the ability of wine lactic acid bacteria to degrade arginine, although in media containing relatively high concentrations (>0.5%) of fructose, ammonia formation is inhibited. PMID:16534912

  3. Antibacterial effects of enniatins J(1) and J(3) on pathogenic and lactic acid bacteria.

    PubMed

    Sebastià, Natividad; Meca, Giuseppe; Soriano, José Miguel; Mañes, Jordi

    2011-10-01

    Enniatins (ENs) are N-methylated cyclohexadepsipeptides, secondary metabolites produced by various species of the genus Fusarium. They are known to act as antifungal, antiyeast and antibacterial and to possess antiinsecticidal and phytotoxic properties. In this study we evaluated for the first time the antibiotic effect of pure fractions of EN J(1) and J(3) on several pathogenic strains and lactic acid bacteria. The ENs J(1) and J(3) were purified from the fermentation extract of Fusarium solani growth on solid medium of wheat kamut, using the technique of the low pressure liquid chromatography (LPLC) followed by a semipreparative liquid chromatography (LC). The purity and the structure of the isolated compound were confirmed by electrospray ionization-mass spectrometry study-linear ion trap (ESI-MS-LIT). The use of both chromatographic techniques have permitted to produce and purify 47mg of the En J(1) and 50mg of the EN J(3) with a mean purity of 98% completely characterized with the technique of the ESI-MS-LIT. Microbial bioassay analyses were carried out by incubation in MRSA and TSA for acid lactic and pathogenic bacteria, respectively during 24h at 37°C. None of the tested strains were inhibited by a 1ng dose of EN J(1) and J(3). These compounds were only not effective against Listeria monocytogenes, Pseudomonas aeruginosa and Salmonella enteric. This study highlight ENs J(1) and J(3) could be potentially effective antibacterial agents against several pathogenic and lactic acid bacteria.

  4. Comparison of dry medium culture plates for mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet products.

    PubMed

    Park, Junghyun; Kim, Myunghee

    2013-12-01

    This study was performed to compare the performance of Sanita-Kun dry medium culture plate with those of traditional culture medium and Petrifilm dry medium culture plate for the enumeration of the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet. Mesophilic aerobic bacteria were comparatively evaluated in milk, ice cream, ham, and codfish fillet using Sanita-Kun aerobic count (SAC), Petrifilm aerobic count (PAC), and traditional plate count agar (PCA) media. According to the results, all methods showed high correlations of 0.989~1.000 and no significant differences were observed for enumerating the mesophilic aerobic bacteria in the tested food products. SAC method was easier to perform and count colonies efficiently as compared to the PCA and PAC methods. Therefore, we concluded that the SAC method offers an acceptable alternative to the PCA and PAC methods for counting the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet products.

  5. Development of radiation sterilized dip slides for enumerating lactic acid bacteria and total count in foodstuffs

    NASA Astrophysics Data System (ADS)

    Eisenberg, E.; Padova, R.; Kirsch, E.; Weissman, Sh.; Hirshfeld, T.; Shenfeld, A.

    APT agar (APT) used for enumeration of lactic acid bacteria and Plate Count agar (PCA) applied for total count were sterilized by gamma radiation using radiation dose of 10-15 kGy. Radiosterilized PCA and APT modified by adding catalase prior to irradiation, or APT with increased content of yeast extract performed, as well as, the heat sterilized commercial media. Growth performance was evaluated on several strains of microorganisms, as well as, by enumeration of bacteria in food products. Radiosterilization of culture media in final packaging, can be applied to produce dip slide kits containing PCA or APT.

  6. Genotypic identification of some lactic acid bacteria by amplified fragment length polymorphism analysis and investigation of their potential usage as starter culture combinations in Beyaz cheese manufacture.

    PubMed

    Karahan, A G; Başyiğit Kiliç, G; Kart, A; Sanlidere Aloğlu, H; Oner, Z; Aydemir, S; Erkuş, O; Harsa, S

    2010-01-01

    In this study, 2 different starter culture combinations were prepared for cheesemaking. Starter culture combinations were formed from 8 strains of lactic acid bacteria. They were identified as Lactococcus lactis ssp. lactis (2 strains), Lactobacillus plantarum (5 strains), and Lactobacillus paraplantarum (1 strain) by amplified fragment length polymorphism analysis. The effects of these combinations on the physicochemical and microbiological properties of Beyaz cheeses were investigated. These cheeses were compared with Beyaz cheeses that were produced with a commercial starter culture containing Lc. lactis ssp. lactis and Lc. lactis ssp. cremoris as control. All cheeses were ripened in brine at 4 degrees C for 90 d. Dry matter, fat in dry matter, titratable acidity, pH, salt in dry matter, total N, water-soluble N, and ripening index were determined. Sodium dodecyl sulfate-PAGE patterns of cheeses showed that alpha(S)-casein and beta-casein degraded slightly during the ripening period. Lactic acid bacteria, total mesophilic aerobic bacteria, yeast, molds, and coliforms were also counted. All analyses were repeated twice during d 7, 30, 60, and 90. The starter culture combinations were found to be significantly different from the control group in pH, salt content, and lactobacilli, lactococci, and total mesophilic aerobic bacteria counts, whereas the cheeses were similar in fat, dry matter content, and coliform, yeast, and mold counts. The sensory analysis of cheeses indicated that textural properties of control cheeses presented somewhat lower scores than those of the test groups. The panelists preferred the tastes of treatment cheeses, whereas cheeses with starter culture combinations and control cheeses had similar scores for appearance and flavor. These results indicated that both starter culture combinations are suitable for Beyaz cheese production.

  7. Heterologous surface display on lactic acid bacteria: non-GMO alternative?

    PubMed

    Zadravec, Petra; Štrukelj, Borut; Berlec, Aleš

    2015-01-01

    Lactic acid bacteria (LAB) are food-grade hosts for surface display with potential applications in food and therapy. Alternative approaches to surface display on LAB would avoid the use of recombinant DNA technology and genetically-modified organism (GMO)-related regulatory requirements. Non-covalent surface display of proteins can be achieved by fusing them to various cell-wall binding domains, of which the Lysine motif domain (LysM) is particularly well studied. Fusion proteins have been isolated from recombinant bacteria or from their growth medium and displayed on unmodified bacteria, enabling heterologous surface display. This was demonstrated on non-viable cells devoid of protein content, termed bacteria-like particles, and on various species of genus Lactobacillus. Of the latter, Lactobacillus salivarius ATCC 11741 was recently shown to be particularly amenable for LysM-mediated display. Possible regulatory implications of heterologous surface display are discussed, particularly those relevant for the European Union.

  8. Heterologous surface display on lactic acid bacteria: non-GMO alternative?

    PubMed Central

    Zadravec, Petra; Štrukelj, Borut; Berlec, Aleš

    2015-01-01

    Lactic acid bacteria (LAB) are food-grade hosts for surface display with potential applications in food and therapy. Alternative approaches to surface display on LAB would avoid the use of recombinant DNA technology and genetically-modified organism (GMO)-related regulatory requirements. Non-covalent surface display of proteins can be achieved by fusing them to various cell-wall binding domains, of which the Lysine motif domain (LysM) is particularly well studied. Fusion proteins have been isolated from recombinant bacteria or from their growth medium and displayed on unmodified bacteria, enabling heterologous surface display. This was demonstrated on non-viable cells devoid of protein content, termed bacteria-like particles, and on various species of genus Lactobacillus. Of the latter, Lactobacillus salivarius ATCC 11741 was recently shown to be particularly amenable for LysM-mediated display. Possible regulatory implications of heterologous surface display are discussed, particularly those relevant for the European Union. PMID:25880164

  9. Culture-independent analysis of lactic acid bacteria diversity associated with mezcal fermentation.

    PubMed

    Narváez-Zapata, J A; Rojas-Herrera, R A; Rodríguez-Luna, I C; Larralde-Corona, C P

    2010-11-01

    Mezcal is an alcoholic beverage obtained from the distillation of fermented juices of cooked Agave spp. plant stalks (agave must), and each region in Mexico with denomination of origin uses defined Agave species to prepare mezcal with unique organoleptic characteristics. During fermentation to produce mezcal in the state of Tamaulipas, not only alcohol-producing yeasts are involved, but also a lactic acid bacterial community that has not been characterized yet. In order to address this lack of knowledge on this traditional Mexican beverage, we performed a DGGE-16S rRNA analysis of the lactic acid bacterial diversity and metabolite accumulation during the fermentation of a typical agave must that is rustically produced in San Carlos County (Tamaulipas, Mexico). The analysis of metabolite production indicated a short but important malolactic fermentation stage not previously described for mezcal. The denaturing gradient gel electrophoresis (DGGE) analysis of the 16S rRNA genes showed a distinctive lactic acid bacterial community composed mainly of Pediococcus parvulus, Lactobacillus brevis, Lactobacillus composti, Lactobacillus parabuchneri, and Lactobacillus plantarum. Some atypical genera such as Weissella and Bacillus were also found in the residual must. Our results suggest that the lactic acid bacteria could strongly be implicated in the organoleptic attributes of this traditional Mexican distilled beverage.

  10. Local domestication of lactic acid bacteria via cassava beer fermentation

    PubMed Central

    Meadow, James F.; Liebert, Melissa A.; Cepon-Robins, Tara J.; Gildner, Theresa E.; Urlacher, Samuel S.; Bohannan, Brendan J.M.; Snodgrass, J. Josh; Sugiyama, Lawrence S.

    2014-01-01

    Cassava beer, or chicha, is typically consumed daily by the indigenous Shuar people of the Ecuadorian Amazon. This traditional beverage made from cassava tuber (Manihot esculenta) is thought to improve nutritional quality and flavor while extending shelf life in a tropical climate. Bacteria responsible for chicha fermentation could be a source of microbes for the human microbiome, but little is known regarding the microbiology of chicha. We investigated bacterial community composition of chicha batches using Illumina high-throughput sequencing. Fermented chicha samples were collected from seven Shuar households in two neighboring villages in the Morona-Santiago region of Ecuador, and the composition of the bacterial communities within each chicha sample was determined by sequencing a region of the 16S ribosomal gene. Members of the genus Lactobacillus dominated all samples. Significantly greater phylogenetic similarity was observed among chicha samples taken within a village than those from different villages. Community composition varied among chicha samples, even those separated by short geographic distances, suggesting that ecological and/or evolutionary processes, including human-mediated factors, may be responsible for creating locally distinct ferments. Our results add to evidence from other fermentation systems suggesting that traditional fermentation may be a form of domestication, providing endemic beneficial inocula for consumers, but additional research is needed to identify the mechanisms and extent of microbial dispersal. PMID:25071997

  11. Effect of phenolic acids on glucose and organic acid metabolism by lactic acid bacteria from wine.

    PubMed

    Campos, Francisco M; Figueiredo, Ana R; Hogg, Tim A; Couto, José A

    2009-06-01

    The influence of phenolic (p-coumaric, caffeic, ferulic, gallic and protocatechuic) acids on glucose and organic acid metabolism by two strains of wine lactic acid bacteria (Oenococcus oeni VF and Lactobacillus hilgardii 5) was investigated. Cultures were grown in modified MRS medium supplemented with different phenolic acids. Cellular growth was monitored and metabolite concentrations were determined by HPLC-RI. Despite the strong inhibitory effect of most tested phenolic acids on the growth of O. oeni VF, the malolactic activity of this strain was not considerably affected by these compounds. While less affected in its growth, the capacity of L. hilgardii 5 to degrade malic acid was clearly diminished. Except for gallic acid, the addition of phenolic acids delayed the metabolism of glucose and citric acid in both strains tested. It was also found that the presence of hydroxycinnamic acids (p-coumaric, caffeic and ferulic) increased the yield of lactic and acetic acid production from glucose by O. oeni VF and not by L. hilgardii 5. The results show that important oenological characteristics of wine lactic acid bacteria, such as the malolactic activity and the production of volatile organic acids, may be differently affected by the presence of phenolic acids, depending on the bacterial species or strain.

  12. Probiotic potential of noni juice fermented with lactic acid bacteria and bifidobacteria.

    PubMed

    Wang, Chung-Yi; Ng, Chang-Chai; Su, Hsuan; Tzeng, Wen-Sheng; Shyu, Yuan-Tay

    2009-01-01

    The present study assesses the feasibility of noni as a raw substrate for the production of probiotic noni juice by lactic acid bacteria (Lactobacilluscasei and Lactobacillus plantarum) and bifidobacteria (Bifidobacteriumlongum). Changes in pH, acidity, sugar content, cell survival and antioxidant properties during fermentation were monitored. All tested strains grew well on noni juice, reaching nearly 10⁹ colony-forming units/ml after 48 h fermentation. L.casei produced less lactic acid than B.longum and L. plantarum. After 4 weeks of cold storage at 4°C, B.longum and L. plantarum survived under low-pH conditions in fermented noni juice. In contrast, L.casei exhibited no cell viability after 3 weeks. Moreover, noni juice fermented with B.longum had a high antioxidant capacity that did not differ significantly (P <0.05) from that of lactic acid bacteria. Finally, we found that B.longum and L. plantarum are optimal probiotics for fermentation with noni juice.

  13. Isolation of thermophilic L-lactic acid producing bacteria showing homo-fermentative manner under high aeration condition.

    PubMed

    Tongpim, Saowanit; Meidong, Ratchanu; Poudel, Pramod; Yoshino, Satoshi; Okugawa, Yuki; Tashiro, Yukihiro; Taniguchi, Masayuki; Sakai, Kenji

    2014-03-01

    By applying non-sterile open fermentation of food waste, various thermotolerant l-lactic acid-producing bacteria were isolated and identified. The predominant bacterial isolates showing higher accumulation of l-lactic acid belong to 3 groups of Bacillus coagulans, according to their 16S rRNA gene sequence similarities. B. coagulans strains M21 and M36 produced high amounts of l-lactic acid of high optical purity and lactic acid selectivity in model kitchen refuse medium and glucose-yeast extract-peptone medium. Other thermotolerant isolates resembling to Bacillus humi, B. ruris, B. subtilis, B. niacini and B. soli were also identified. These bacteria produced low amounts of l-lactic acid of more than 99% optical purity. All isolated strains showed the highest growth rate at temperatures around 55-60°C. They showed unique responses to various oxygen supply conditions. The majority of isolates produced l-lactic acid at a low overall oxygen transfer coefficient (KLa); however, acetic acid was produced instead of l-lactic acid at a high KLa. B. coagulans M21 was the only strain that produced high, consistent, and reproducible amounts of optically pure l-lactic acid (>99% optical purity) under high and low KLa conditions in a homo-fermentative manner.

  14. The aflatoxin B1 isolating potential of two lactic acid bacteria

    PubMed Central

    Hamidi, Adel; Mirnejad, Reza; Yahaghi, Emad; Behnod, Vahid; Mirhosseini, Ali; Amani, Sajad; Sattari, Sara; Darian, Ebrahim Khodaverdi

    2013-01-01

    Objective To determine lactic acid bacteria's capability to enhance the process of binding and isolating aflatoxin B1 and to utilize such lactic acid bacteria as a food supplement or probiotic products for preventing absorption of aflatoxin B1 in human and animal bodies. Methods In the present research, the bacteria were isolated from five different sources. For surveying the capability of the bacteria in isolating aflatoxin B1, ELISA method was implemented, and for identifying the resultant strains through 16S rRNA sequencing method, universal primers were applied. Results Among the strains which were isolated, two strains of Lactobacillus pentosus and Lactobacillus beveris exhibited the capability of absorbing and isolating aflatoxin B1 by respectively absorbing and discharging 17.4% and 34.7% of the aforementioned toxin existing in the experiment solution. Conclusions Strains of Lactobacillus pentosus and Lactobacillus beveris were isolated from human feces and local milk samples, respectively. And both strains has the ability to isolate or bind with aflatoxin B1. PMID:23998015

  15. Phenotypic and genotypic characterization of lactic acid bacteria isolated from Artisanal Italian goat cheese.

    PubMed

    Colombo, E; Franzetti, L; Frusca, M; Scarpellini, M

    2010-04-01

    The lactic acid bacteria community in traditional goat cheese produced in three dairies in Valsesia (Piemonte, Italy) was studied at different steps of the manufacturing process. These cheeses were produced from raw milk without starter bacteria, and no protocol was followed during the manufacturing process. Three hundred thirty-two isolates were characterized and grouped by results of both morphophysiological tests and random amplification of polymorphic DNA plus PCR analysis. Bacteria were identified by partial sequencing of the 16S rRNA gene. Lactococci were the dominant lactic acid bacteria in raw milk. Their initial numbers ranged from 5 to 7 log CFU ml(-1). Their levels increased during manufacturing and decreased during ripening. The growth trend for enterococci was comparable to that of lactococci, although enterococci counts were lower. Lactococcus lactis subsp. cremoris, Lactococcus garviae, and Enterococcus faecalis were the most frequently isolated species during goat cheese manufacturing, whereas the highest numbers of Enterococcus (E. faecium, E. durans, E. gilvus, and E. casseliflavus) were isolated with the greatest frequency from ripened cheese samples. Occasionally, Leuconostoc mesenteroides, Leuconostoc lactis, and Lactobacillus paraplantarum also were isolated.

  16. Phenotypic and Genotypic Characterization of Some Lactic Acid Bacteria Isolated from Bee Pollen: A Preliminary Study

    PubMed Central

    BELHADJ, Hani; HARZALLAH, Daoud; BOUAMRA, Dalila; KHENNOUF, Seddik; Dahamna, Saliha; GHADBANE, Mouloud

    2014-01-01

    In the present work, five hundred and sixty-seven isolates of lactic acid bacteria were recovered from raw bee pollen grains. All isolates were screened for their antagonistic activity against both Gram-positive and Gram-negative pathogenic bacteria. Neutralized supernatants of 54 lactic acid bacteria (LAB) cultures from 216 active isolates inhibited the growth of indicator bacteria. They were phenotypically characterized, based on the fermentation of 39 carbohydrates. Using the simple matching coefficient and unweighted pair group algorithm with arithmetic averages (UPGMA), seven clusters with other two members were defined at the 79% similarity level. The following species were characterized: Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Pediococcus acidilactici, Pediococcus pentosaceus, and unidentified lactobacilli. Phenotypic characteristics of major and minor clusters were also identified. Partial sequencing of the 16S rRNA gene of representative isolates from each cluster was performed, and ten strains were assigned to seven species: Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Lactobacillus ingluviei, Pediococcus pentosaceus, Lactobacillus acidipiscis and Weissella cibaria. The molecular method used failed to determine the exact taxonomic status of BH0900 and AH3133. PMID:24936378

  17. Molecular chaperones in lactic acid bacteria: physiological consequences and biochemical properties.

    PubMed

    Sugimoto, Shinya; Abdullah-Al-Mahin; Sonomoto, Kenji

    2008-10-01

    Recently, lactic acid bacteria (LAB) have attracted much attention because of their potential application to probiotics and industrial applications as starters for dairy products or lactic acid fermentation. Additional emphasis is also being paid to them as commensal bacteria in gastrointestinal tract. Since LAB exhibit a stress response, insight into the relationship between stress proteins such as molecular chaperones and stress tolerance or adaptation is increasing gradually along with current research examining these important bacteria. Similar to other bacteria, one of the major stress-response systems in LAB is the expression of molecular chaperones. The recently completed genome sequencing of various LAB strains, combined with the development of advanced molecular techniques, have enabled us to identify molecular chaperones and to understand their regulation systems in response to various stresses. Furthermore, recent biochemical studies provided novel insight into the molecular mechanisms of LAB chaperone systems. This review highlights the physiological consequences and biochemical properties of molecular chaperones (especially sHsps, Hsp70, and Hsp100) in LAB and their use in biotechnological applications.

  18. Application of Lactic Acid Bacteria (LAB) in freshness keeping of tilapia fillets as sashimi

    NASA Astrophysics Data System (ADS)

    Cao, Rong; Liu, Qi; Chen, Shengjun; Yang, Xianqing; Li, Laihao

    2015-08-01

    Aquatic products are extremely perishable food commodities. Developing methods to keep the freshness of fish represents a major task of the fishery processing industry. Application of Lactic Acid Bacteria (LAB) as food preservative is a novel approach. In the present study, the possibility of using lactic acid bacteria in freshness keeping of tilapia fillets as sashimi was examined. Fish fillets were dipped in Lactobacillus plantarum 1.19 (obtained from China General Microbiological Culture Collection Center) suspension as LAB-treated group. Changes in K-value, APC, sensory properties and microbial flora were analyzed. Results showed that LAB treatment slowed the increase of K-value and APC in the earlier storage, and caused a smooth decrease in sensory score. Gram-negative bacteria dominated during refrigerated storage, with Pseudomonas and Aeromonas being relatively abundant. Lactobacillus plantarum 1.19 had no obvious inhibitory effect against these Gram-negatives. However, Lactobacillus plantarum 1.19 changed the composition of Gram-positive bacteria. No Micrococcus were detected and the proportion of Staphylococcus decreased in the spoiled LAB-treated samples. The period that tilapia fillets could be used as sashimi material extended from 24 h to 48 h after LAB treatment. The potential of using LAB in sashimi processing was confirmed.

  19. Increased d-lactic Acid intestinal bacteria in patients with chronic fatigue syndrome.

    PubMed

    Sheedy, John R; Wettenhall, Richard E H; Scanlon, Denis; Gooley, Paul R; Lewis, Donald P; McGregor, Neil; Stapleton, David I; Butt, Henry L; DE Meirleir, Kenny L

    2009-01-01

    Patients with chronic fatigue syndrome (CFS) are affected by symptoms of cognitive dysfunction and neurological impairment, the cause of which has yet to be elucidated. However, these symptoms are strikingly similar to those of patients presented with D-lactic acidosis. A significant increase of Gram positive facultative anaerobic faecal microorganisms in 108 CFS patients as compared to 177 control subjects (p<0.01) is presented in this report. The viable count of D-lactic acid producing Enterococcus and Streptococcus spp. in the faecal samples from the CFS group (3.5 x 10(7) cfu/L and 9.8 x 10(7) cfu/L respectively) were significantly higher than those for the control group (5.0 x 10(6) cfu/L and 8.9 x 10(4) cfu/L respectively). Analysis of exometabolic profiles of Enterococcus faecalis and Streptococcus sanguinis, representatives of Enterococcus and Streptococcus spp. respectively, by NMR and HPLC showed that these organisms produced significantly more lactic acid (p<0.01) from (13)C-labeled glucose, than the Gram negative Escherichia coli. Further, both E. faecalis and S. sanguinis secrete more D-lactic acid than E. coli. This study suggests a probable link between intestinal colonization of Gram positive facultative anaerobic D-lactic acid bacteria and symptom expressions in a subgroup of patients with CFS. Given the fact that this might explain not only neurocognitive dysfunction in CFS patients but also mitochondrial dysfunction, these findings may have important clinical implications.

  20. Hydrogen evolution by strictly aerobic hydrogen bacteria under anaerobic conditions.

    PubMed

    Kuhn, M; Steinbüchel, A; Schlegel, H G

    1984-08-01

    When strains and mutants of the strictly aerobic hydrogen-oxidizing bacterium Alcaligenes eutrophus are grown heterotrophically on gluconate or fructose and are subsequently exposed to anaerobic conditions in the presence of the organic substrates, molecular hydrogen is evolved. Hydrogen evolution started immediately after the suspension was flushed with nitrogen, reached maximum rates of 70 to 100 mumol of H2 per h per g of protein, and continued with slowly decreasing rates for at least 18 h. The addition of oxygen to an H2-evolving culture, as well as the addition of nitrate to cells (which had formed the dissimilatory nitrate reductase system during the preceding growth), caused immediate cessation of hydrogen evolution. Formate is not the source of H2 evolution. The rates of H2 evolution with formate as the substrate were lower than those with gluconate. The formate hydrogenlyase system was not detectable in intact cells or crude cell extracts. Rather the cytoplasmic, NAD-reducing hydrogenase is involved by catalyzing the release of excessive reducing equivalents under anaerobic conditions in the absence of suitable electron acceptors. This conclusion is based on the following experimental results. H2 is formed only by cells which had synthesized the hydrogenases during growth. Mutants lacking the membrane-bound hydrogenase were still able to evolve H2. Mutants lacking the NAD-reducing or both hydrogenases were unable to evolve H2.

  1. Aerobic biodegradation of propylene glycol by soil bacteria.

    PubMed

    Toscano, Giuseppe; Cavalca, Lucia; Letizia Colarieti, M; Scelza, Rosalia; Scotti, Riccardo; Rao, Maria A; Andreoni, Vincenza; Ciccazzo, Sonia; Greco, Guido

    2013-09-01

    Propylene glycol (PG) is a main component of aircraft deicing fluids and its extensive use in Northern airports is a source of soil and groundwater contamination. Bacterial consortia able to grow on PG as sole carbon and energy source were selected from soil samples taken along the runways of Oslo Airport Gardermoen site (Norway). DGGE analysis of enrichment cultures showed that PG-degrading populations were mainly composed by Pseudomonas species, although Bacteroidetes were found, as well. Nineteen bacterial strains, able to grow on PG as sole carbon and energy source, were isolated and identified as different Pseudomonas species. Maximum specific growth rate of mixed cultures in the absence of nutrient limitation was 0.014 h(-1) at 4 °C. Substrate C:N:P molar ratios calculated on the basis of measured growth yields are in good agreement with the suggested values for biostimulation reported in literature. Therefore, the addition of nutrients is suggested as a suitable technique to sustain PG aerobic degradation at the maximum rate by autochthonous microorganisms of unsaturated soil profile.

  2. Coexistence of Lactic Acid Bacteria and Potential Spoilage Microbiota in a Dairy Processing Environment.

    PubMed

    Stellato, Giuseppina; De Filippis, Francesca; La Storia, Antonietta; Ercolini, Danilo

    2015-11-01

    Microbial contamination in food processing plants can play a fundamental role in food quality and safety. In this study, the microbiota in a dairy plant was studied by both 16S rRNA- and 26S rRNA-based culture-independent high-throughput amplicon sequencing. Environmental samples from surfaces and tools were studied along with the different types of cheese produced in the same plant. The microbiota of environmental swabs was very complex, including more than 200 operational taxonomic units with extremely variable relative abundances (0.01 to 99%) depending on the species and sample. A core microbiota shared by 70% of the samples indicated a coexistence of lactic acid bacteria with a remarkable level of Streptococcus thermophilus and possible spoilage-associated bacteria, including Pseudomonas, Acinetobacter, and Psychrobacter, with a relative abundance above 50%. The most abundant yeasts were Kluyveromyces marxianus, Yamadazyma triangularis, Trichosporon faecale, and Debaryomyces hansenii. Beta-diversity analyses showed a clear separation of environmental and cheese samples based on both yeast and bacterial community structure. In addition, predicted metagenomes also indicated differential distribution of metabolic pathways between the two categories of samples. Cooccurrence and coexclusion pattern analyses indicated that the occurrence of potential spoilers was excluded by lactic acid bacteria. In addition, their persistence in the environment can be helpful to counter the development of potential spoilers that may contaminate the cheeses, with possible negative effects on their microbiological quality.

  3. A glutamic acid-producing lactic acid bacteria isolated from Malaysian fermented foods.

    PubMed

    Zareian, Mohsen; Ebrahimpour, Afshin; Bakar, Fatimah Abu; Mohamed, Abdul Karim Sabo; Forghani, Bita; Ab-Kadir, Mohd Safuan B; Saari, Nazamid

    2012-01-01

    l-glutamaic acid is the principal excitatory neurotransmitter in the brain and an important intermediate in metabolism. In the present study, lactic acid bacteria (218) were isolated from six different fermented foods as potent sources of glutamic acid producers. The presumptive bacteria were tested for their ability to synthesize glutamic acid. Out of the 35 strains showing this capability, strain MNZ was determined as the highest glutamic-acid producer. Identification tests including 16S rRNA gene sequencing and sugar assimilation ability identified the strain MNZ as Lactobacillus plantarum. The characteristics of this microorganism related to its glutamic acid-producing ability, growth rate, glucose consumption and pH profile were studied. Results revealed that glutamic acid was formed inside the cell and excreted into the extracellular medium. Glutamic acid production was found to be growth-associated and glucose significantly enhanced glutamic acid production (1.032 mmol/L) compared to other carbon sources. A concentration of 0.7% ammonium nitrate as a nitrogen source effectively enhanced glutamic acid production. To the best of our knowledge this is the first report of glutamic acid production by lactic acid bacteria. The results of this study can be further applied for developing functional foods enriched in glutamic acid and subsequently γ-amino butyric acid (GABA) as a bioactive compound.

  4. Coexistence of Lactic Acid Bacteria and Potential Spoilage Microbiota in a Dairy Processing Environment

    PubMed Central

    Stellato, Giuseppina; De Filippis, Francesca; La Storia, Antonietta

    2015-01-01

    Microbial contamination in food processing plants can play a fundamental role in food quality and safety. In this study, the microbiota in a dairy plant was studied by both 16S rRNA- and 26S rRNA-based culture-independent high-throughput amplicon sequencing. Environmental samples from surfaces and tools were studied along with the different types of cheese produced in the same plant. The microbiota of environmental swabs was very complex, including more than 200 operational taxonomic units with extremely variable relative abundances (0.01 to 99%) depending on the species and sample. A core microbiota shared by 70% of the samples indicated a coexistence of lactic acid bacteria with a remarkable level of Streptococcus thermophilus and possible spoilage-associated bacteria, including Pseudomonas, Acinetobacter, and Psychrobacter, with a relative abundance above 50%. The most abundant yeasts were Kluyveromyces marxianus, Yamadazyma triangularis, Trichosporon faecale, and Debaryomyces hansenii. Beta-diversity analyses showed a clear separation of environmental and cheese samples based on both yeast and bacterial community structure. In addition, predicted metagenomes also indicated differential distribution of metabolic pathways between the two categories of samples. Cooccurrence and coexclusion pattern analyses indicated that the occurrence of potential spoilers was excluded by lactic acid bacteria. In addition, their persistence in the environment can be helpful to counter the development of potential spoilers that may contaminate the cheeses, with possible negative effects on their microbiological quality. PMID:26341209

  5. Identification and Characterization of Lactic Acid Bacteria in a Commercial Probiotic Culture

    PubMed Central

    MENCONI, Anita; KALLAPURA, Gopala; LATORRE, Juan D.; MORGAN, Marion J.; PUMFORD, Neil R.; HARGIS, Billy M.; TELLEZ, Guillermo

    2014-01-01

    The aim of the present study was to describe the identification and characterization (physiological properties) of two strains of lactic acid bacteria (LAB 18 and 48) present in a commercial probiotic culture, FloraMax®-B11. Isolates were characterized morphologically, and identified biochemically. In addition, the MIDI System ID, the Biolog ID System, and 16S rRNA sequence analyses for identification of LAB 18 and LAB 48 strains were used to compare the identification results. Tolerance and resistance to acidic pH, high osmotic concentration of NaCl, and bile salts were tested in broth medium. In vitro assessment of antimicrobial activity against enteropathogenic bacteria and susceptibility to antibiotics were also tested. The results obtained in this study showed tolerance of LAB 18 and LAB 48 to pH 3.0, 6.5% NaCl and a high bile salt concentration (0.6%). Both strains evaluated showed in vitro antibacterial activity against Salmonella enterica serovar Enteritidis, Escherichia coli (O157:H7), and Campylobacter jejuni. These are important characteristics of lactic acid bacteria that should be evaluated when selecting strains to be used as probiotics. Antimicrobial activity of these effective isolates may contribute to efficacy, possibly by direct antimicrobial activity in vivo. PMID:24936379

  6. Screening of species-specific lactic acid bacteria for veal calves multi-strain probiotic adjuncts.

    PubMed

    Ripamonti, Barbara; Agazzi, Alessandro; Bersani, Carla; De Dea, Paola; Pecorini, Chiara; Pirani, Silvia; Rebucci, Raffaella; Savoini, Giovanni; Stella, Simone; Stenico, Alberta; Tirloni, Erica; Domeneghini, Cinzia

    2011-06-01

    The selection of promising specific species of lactic acid bacteria with potential probiotic characteristics is of particular interest in producing multi species-specific probiotic adjuncts in veal calves rearing. The aim of the present work was to select and evaluate in vitro the functional activity of lactic acid bacteria, Bifidobacterium longum and Bacillus coagulans strains isolated from veal calves in order to assess their potential use as multi species-specific probiotics for veal calves. For this purpose, bacterial strains isolated from faeces collected from 40 healthy 50-day-calves, were identified by RiboPrinter and 16s rRNA gene sequence. The most frequent strains belonged to the species B. longum, Streptococcus bovis, Lactobacillus animalis and Streptococcus macedonicus. Among these, 7 strains were chosen for testing their probiotic characteristics in vitro. Three strains, namely L. animalis SB310, Lactobacillus paracasei subsp. paracasei SB137 and B. coagulans SB117 showed varying individual but promising capabilities to survive in the gastrointestinal tract, to adhere, to produce antimicrobial compounds. These three selected species-specific bacteria demonstrated in vitro, both singularly and mixed, the functional properties needed for their use as potential probiotics in veal calves.

  7. Ethanol Production by Selected Intestinal Microorganisms and Lactic Acid Bacteria Growing under Different Nutritional Conditions

    PubMed Central

    Elshaghabee, Fouad M. F.; Bockelmann, Wilhelm; Meske, Diana; de Vrese, Michael; Walte, Hans-Georg; Schrezenmeir, Juergen; Heller, Knut J.

    2016-01-01

    To gain some specific insight into the roles microorganisms might play in non-alcoholic fatty liver disease (NAFLD), some intestinal and lactic acid bacteria and one yeast (Anaerostipes caccae, Bacteroides thetaiotaomicron, Bifidobacterium longum, Enterococcus fecalis, Escherichia coli, Lactobacillus acidophilus, Lactobacillus fermentum, Lactobacillus plantarum, Weissella confusa, Saccharomyces cerevisiae) were characterized by high performance liquid chromatography for production of ethanol when grown on different carbohydrates: hexoses (glucose and fructose), pentoses (arabinose and ribose), disaccharides (lactose and lactulose), and inulin. Highest amounts of ethanol were produced by S. cerevisiae, L. fermentum, and W. confusa on glucose and by S. cerevisiae and W. confusa on fructose. Due to mannitol-dehydrogenase expressed in L. fermentum, ethanol production on fructose was significantly (P < 0.05) reduced. Pyruvate and citrate, two potential electron acceptors for regeneration of NAD+/NADP+, drastically reduced ethanol production with acetate produced instead in L. fermentum grown on glucose and W. confusa grown on glucose and fructose, respectively. In fecal slurries prepared from feces of four overweight volunteers, ethanol was found to be produced upon addition of fructose. Addition of A. caccae, L. acidophilus, L. fermentum, as well as citrate and pyruvate, respectively, abolished ethanol production. However, addition of W. confusa resulted in significantly (P < 0.05) increased production of ethanol. These results indicate that microorganisms like W. confusa, a hetero-fermentative, mannitol-dehydrogenase negative lactic acid bacterium, may promote NAFLD through ethanol produced from sugar fermentation, while other intestinal bacteria and homo- and hetero-fermentative but mannitol-dehydrogenase positive lactic acid bacteria may not promote NAFLD. Also, our studies indicate that dietary factors interfering with gastrointestinal microbiota and microbial

  8. Testing for aerobic heterotrophic bacteria allows no prediction of contamination with potentially pathogenic bacteria in the output water of dental chair units

    PubMed Central

    Bristela, Margit; Skolka, Astrid; Schmid-Schwap, Martina; Piehslinger, Eva; Indra, Alexander; Wewalka, Günther; Stauffer, Fritz

    2012-01-01

    Background: Currently, to our knowledge, quality of output water of dental chair units is not covered by specific regulations in the European Union, and national recommendations are heterogeneous. In Germany, water used in dental chair units must follow drinking water quality. In the United States of America, testing for aerobic heterotrophic bacteria is recommended. The present study was performed to evaluate whether the counts of aerobic heterotrophic bacteria correlate with the presence of potentially pathogenic bacteria such as Legionella spp. or Pseudomonas aeruginosa. Methods: 71 samples were collected from 26 dental chair units with integrated disinfection device and 31 samples from 15 outlets of the water distribution pipework within the department were examined. Samples were tested for aerobic heterotrophic bacteria at 35°C and 22°C using different culture media and for Legionella spp. and for Pseudomonas aeruginosa. Additionally, strains of Legionella pneumophila serogroup 1 were typed with monoclonal antibodies and representative samples of Legionella pneumophila serogroup 1 were typed by sequence based typing. Results: Our results showed a correlation between different agars for aerobic heterotrophic bacteria but no correlation for the count of aerobic heterotrophic bacteria and the presence of Legionella spp. or Pseudomonas aeruginosa. Conclusion: Testing for aerobic heterotrophic bacteria in output water or water distribution pipework within the departments alone is without any value for predicting whether the water is contaminated with potentially pathogenic bacteria like Legionella spp. or Pseudomonas aeruginosa. PMID:22558046

  9. Tyramine and phenylethylamine production among lactic acid bacteria isolated from wine.

    PubMed

    Landete, José María; Pardo, Isabel; Ferrer, Sergi

    2007-04-20

    The ability of wine lactic acid bacteria to produce tyramine and phenylethylamine was investigated by biochemical and genetic methods. An easy and accurate plate medium was developed to detect tyramine-producer strains, and a specific PCR assay that detects the presence of tdc gene was employed. All strains possessing the tdc gene were shown to produce tyramine and phenylethylamine. Wines containing high quantities of tyramine and phenylethylamine were found to contain Lactobacillus brevis or Lactobacillus hilgardii. The main tyramine producer was L. brevis. The ability to produce tyramine was absent or infrequent in the rest of the analysed wine species.

  10. [The microflora of sourdough. XVIII. The protein degrading capabilities of lactic acid bacteria in sourdough].

    PubMed

    Spicher, G; Nierle, W

    1984-05-01

    Acidification of the dough by the use of sourdough or acidifiers is necessary not only for good baking quality of rye flour but it is also very important for development of the typical sensory characteristics of rye bread. We confirmed that the lactic acid bacteria of sour dough are proteolytic. Proteolytic effects are observed in the increase of the amino acid content during fermentation. A marked increase was found in the content of leucine, alanine, valine, isoleucine, glutamic acid, glutamine, arginine, lysine, methionine, phenylalanine, tyrosine and serine. Lactobacillus plantarum showed a higher proteolytic activity than L. brevis ssp. lindneri or L. fructivorans.

  11. Lactic acid bacteria and their controversial role in fresh meat spoilage.

    PubMed

    Pothakos, Vasileios; Devlieghere, Frank; Villani, Francesco; Björkroth, Johanna; Ercolini, Danilo

    2015-11-01

    Lactic acid bacteria (LAB) constitute a heterogeneous group that has been widely associated with fresh meat and cooked meat products. They represent a controversial cohort of microbial species that either contribute to spoilage through generation of offensive metabolites and the subsequent organoleptic downgrading of meat or serve as bioprotective agents with strains of certain species causing unperceivable or no alterations. Therefore, significant distinction among biotypes is substantiated by studies determining spoilage potential as a strain-specific trait corroborating the need to revisit the concept of spoilage.

  12. Bacteriocin-Producing Lactic Acid Bacteria Isolated from Traditional Fermented Food

    PubMed Central

    Kormin, Salasiah; Rusul, Gulam; Radu, Son; Ling, Foo Hooi

    2001-01-01

    Lactic Acid Bacteria (LAB) isolated from several traditional fermented foods such as “tempeh”, “tempoyak” and “tapai” were screened for the production of bacteriocin. One strain isolated from “tempeh” gives an inhibitory activity against several LAB. The strain was later identified as Lactobacillus plantarum BS2. Study shows that the inhibitory activity was not caused by hydrogen peroxide, organic acids or bacteriophage. The bacteriocin production was maximum after 10 hours of incubation with an activity of 200 AU/ml. The bacteriocin was found to be sensitive towards trypsin, α-chymotrypsin, β-chymotrypsin, α-amylase and lysozyme. PMID:22973159

  13. [Antagonistic properties of lactic acid bacteria isolated from apparently healthy and osteoporotic women].

    PubMed

    Ohirchuk, K S; Poltavs'ka, O A; Kovalenko, N K

    2013-01-01

    Antagonistic activity of 74 cultures of lactic acid bacteria, isolated from healthy and osteoporotic women-patients aged 50-79 years, has been studied. It has been shown that the inhibitory effect of the strain studied was independent of the health of women (control group of women or patients with osteoporosis), but had strain specificity. Seventeen most active strains of lactobacilli, which showed the highest inhibitory activity against B. cereus, P. aeruginosa, P. vulgaris were selected. Only 6 strains of lactobacillus demonstrated specific antagonistic activity against the test-strains.

  14. Prevention by lactic acid bacteria of the oxidation of human LDL.

    PubMed

    Terahara, M; Kurama, S; Takemoto, N

    2001-08-01

    Ether extracts of lactic acid bacteria were analyzed for prevention of the oxidation of erythrocyte membrane and human low-density lipoprotein in vivo. Streptococcus thermophilus 1131 and Lactobacillus delbrueckii subsp. bulgaricus 2038, yogurt starters, were chosen as test-strains, and ether extracts of these cultures were used as samples. Both strain 1131 and strain 2038 produced radical scavengers and inhibited oxidation of erythrocyte membranes and low-density lipoproteins. The antioxidative activity of strain 2038 was higher than that of strain 1131.

  15. Use of autochthonous lactic acid bacteria starters to ferment mango juice for promoting its probiotic roles.

    PubMed

    Liao, Xue-Yi; Guo, Li-Qiong; Ye, Zhi-Wei; Qiu, Ling-Yan; Gu, Feng-Wei; Lin, Jun-Fang

    2016-05-18

    Strains of Leuconostoc mesenteroides, Pediococcus pentosaceus, and Lactobacillus brevis were identified from mango fruits by partial 16S rDNA gene sequence. Based on the ability of producing mannitol and diacetyl, Leuconostoc mesenteroides MPL18 and MPL39 were selected within the lactic acid bacteria isolates, and used as mixed starters to ferment mango juice (MJ). Both the autochthonous strains grew well in fermented mango juice (FMJ) and remained viable at 9.81 log cfu mL(-1) during 30 days of storage at 4°C. The content of total sugar of FMJ was lower than that of MJ, while the concentration of mannitol was higher than that of MJ, and the concentration of diacetyl was 3.29 ± 0.12 mg L(-1). Among detected organic acids including citric acid, gallic acid, lactic acid, and acetic acid, only citric acid and gallic acid were found in MJ, while all detected organic acids were found in FMJ. The concentration of lactic acid of FMJ was the highest (78.62 ± 13.66 mM) among all detected organic acids. The DPPH radical scavenging capacity of FMJ was higher than that of MJ. Total phenolic compounds were better preserved in FMJ. The acidity and sweetness had a noticeable impact on the overall acceptance of the treated sample.

  16. The Bacteriohopanepolyol Inventory of Novel Aerobic Methane Oxidising Bacteria Reveals New Biomarker Signatures of Aerobic Methanotrophy in Marine Systems.

    PubMed

    Rush, Darci; Osborne, Kate A; Birgel, Daniel; Kappler, Andreas; Hirayama, Hisako; Peckmann, Jörn; Poulton, Simon W; Nickel, Julia C; Mangelsdorf, Kai; Kalyuzhnaya, Marina; Sidgwick, Frances R; Talbot, Helen M

    2016-01-01

    Aerobic methane oxidation (AMO) is one of the primary biologic pathways regulating the amount of methane (CH4) released into the environment. AMO acts as a sink of CH4, converting it into carbon dioxide before it reaches the atmosphere. It is of interest for (paleo)climate and carbon cycling studies to identify lipid biomarkers that can be used to trace AMO events, especially at times when the role of methane in the carbon cycle was more pronounced than today. AMO bacteria are known to synthesise bacteriohopanepolyol (BHP) lipids. Preliminary evidence pointed towards 35-aminobacteriohopane-30,31,32,33,34-pentol (aminopentol) being a characteristic biomarker for Type I methanotrophs. Here, the BHP compositions were examined for species of the recently described novel Type I methanotroph bacterial genera Methylomarinum and Methylomarinovum, as well as for a novel species of a Type I Methylomicrobium. Aminopentol was the most abundant BHP only in Methylomarinovum caldicuralii, while Methylomicrobium did not produce aminopentol at all. In addition to the expected regular aminotriol and aminotetrol BHPs, novel structures tentatively identified as methylcarbamate lipids related to C-35 amino-BHPs (MC-BHPs) were found to be synthesised in significant amounts by some AMO cultures. Subsequently, sediments and authigenic carbonates from methane-influenced marine environments were analysed. Most samples also did not contain significant amounts of aminopentol, indicating that aminopentol is not a useful biomarker for marine aerobic methanotophic bacteria. However, the BHP composition of the marine samples do point toward the novel MC-BHPs components being potential new biomarkers for AMO.

  17. The Bacteriohopanepolyol Inventory of Novel Aerobic Methane Oxidising Bacteria Reveals New Biomarker Signatures of Aerobic Methanotrophy in Marine Systems

    PubMed Central

    Birgel, Daniel; Kappler, Andreas; Hirayama, Hisako; Peckmann, Jörn; Poulton, Simon W.; Nickel, Julia C.; Mangelsdorf, Kai; Kalyuzhnaya, Marina; Sidgwick, Frances R.; Talbot, Helen M.

    2016-01-01

    Aerobic methane oxidation (AMO) is one of the primary biologic pathways regulating the amount of methane (CH4) released into the environment. AMO acts as a sink of CH4, converting it into carbon dioxide before it reaches the atmosphere. It is of interest for (paleo)climate and carbon cycling studies to identify lipid biomarkers that can be used to trace AMO events, especially at times when the role of methane in the carbon cycle was more pronounced than today. AMO bacteria are known to synthesise bacteriohopanepolyol (BHP) lipids. Preliminary evidence pointed towards 35-aminobacteriohopane-30,31,32,33,34-pentol (aminopentol) being a characteristic biomarker for Type I methanotrophs. Here, the BHP compositions were examined for species of the recently described novel Type I methanotroph bacterial genera Methylomarinum and Methylomarinovum, as well as for a novel species of a Type I Methylomicrobium. Aminopentol was the most abundant BHP only in Methylomarinovum caldicuralii, while Methylomicrobium did not produce aminopentol at all. In addition to the expected regular aminotriol and aminotetrol BHPs, novel structures tentatively identified as methylcarbamate lipids related to C-35 amino-BHPs (MC-BHPs) were found to be synthesised in significant amounts by some AMO cultures. Subsequently, sediments and authigenic carbonates from methane-influenced marine environments were analysed. Most samples also did not contain significant amounts of aminopentol, indicating that aminopentol is not a useful biomarker for marine aerobic methanotophic bacteria. However, the BHP composition of the marine samples do point toward the novel MC-BHPs components being potential new biomarkers for AMO. PMID:27824887

  18. Quantitative analyses of the bacterial microbiota of rearing environment, tilapia and common carp cultured in earthen ponds and inhibitory activity of its lactic acid bacteria on fish spoilage and pathogenic bacteria.

    PubMed

    Kaktcham, Pierre Marie; Temgoua, Jules-Bocamdé; Ngoufack Zambou, François; Diaz-Ruiz, Gloria; Wacher, Carmen; Pérez-Chabela, María de Lourdes

    2017-02-01

    The present study aimed to evaluate the bacterial load of water, Nile Tilapia and common Carp intestines from earthen ponds, isolate lactic acid bacteria (LAB) and assess their antimicrobial activity against fish spoilage and pathogenic bacteria. Following enumeration and isolation of microorganisms the antimicrobial activity of the LAB isolates was evaluated. Taxonomic identification of selected antagonistic LAB strains was assessed, followed by partial characterisation of their antimicrobial metabolites. Results showed that high counts (>4 log c.f.u ml(-1) or 8 log c.f.u g(-1)) of total aerobic bacteria were recorded in pond waters and fish intestines. The microbiota were also found to be dominated by Salmonella spp., Vibrio spp., Staphylococcus spp. and Escherichia coli. LAB isolates (5.60%) exhibited potent direct and extracellular antimicrobial activity against the host-derived and non host-derived spoilage and pathogenic bacteria. These antagonistic isolates were identified and Lactococcus lactis subsp. lactis was found as the predominant (42.85%) specie. The strains displayed the ability to produce lactic, acetic, butyric, propionic and valeric acids. Bacteriocin-like inhibitory substances with activity against Gram-positive and Gram-negative (Vibrio spp. and Pseudomonas aeruginosa) bacteria were produced by three L. lactis subsp. lactis strains. In this study, the LAB from the microbiota of fish and pond water showed potent antimicrobial activity against fish spoilage or pathogenic bacteria from the same host or ecological niche. The studied Cameroonian aquatic niche is an ideal source of antagonistic LAB that could be appropriate as new fish biopreservatives or disease control agents in aquaculture under tropical conditions in particular or worldwide in general.

  19. Modelling the effect of lactic acid bacteria from starter- and aroma culture on growth of Listeria monocytogenes in cottage cheese.

    PubMed

    Østergaard, Nina Bjerre; Eklöw, Annelie; Dalgaard, Paw

    2014-10-01

    Four mathematical models were developed and validated for simultaneous growth of mesophilic lactic acid bacteria from added cultures and Listeria monocytogenes, during chilled storage of cottage cheese with fresh- or cultured cream dressing. The mathematical models include the effect of temperature, pH, NaCl, lactic- and sorbic acid and the interaction between these environmental factors. Growth models were developed by combining new and existing cardinal parameter values. Subsequently, the reference growth rate parameters (μref at 25°C) were fitted to a total of 52 growth rates from cottage cheese to improve model performance. The inhibiting effect of mesophilic lactic acid bacteria from added cultures on growth of L. monocytogenes was efficiently modelled using the Jameson approach. The new models appropriately predicted the maximum population density of L. monocytogenes in cottage cheese. The developed models were successfully validated by using 25 growth rates for L. monocytogenes, 17 growth rates for lactic acid bacteria and a total of 26 growth curves for simultaneous growth of L. monocytogenes and lactic acid bacteria in cottage cheese. These data were used in combination with bias- and accuracy factors and with the concept of acceptable simulation zone. Evaluation of predicted growth rates of L. monocytogenes in cottage cheese with fresh- or cultured cream dressing resulted in bias-factors (Bf) of 1.07-1.10 with corresponding accuracy factor (Af) values of 1.11 to 1.22. Lactic acid bacteria from added starter culture were on average predicted to grow 16% faster than observed (Bf of 1.16 and Af of 1.32) and growth of the diacetyl producing aroma culture was on average predicted 9% slower than observed (Bf of 0.91 and Af of 1.17). The acceptable simulation zone method showed the new models to successfully predict maximum population density of L. monocytogenes when growing together with lactic acid bacteria in cottage cheese. 11 of 13 simulations of L

  20. Evaluation of Petrifilm method for enumerating aerobic bacteria in Crottin goat cheese.

    PubMed

    de Sousa, G B; Tamagnini, L M; González, R D; Budde, C E

    2005-01-01

    The Petrifilm Aerobic Count Plate (ACP) developed by 3M laboratories, is a ready-to-use culture medium system, useful for the enumeration of aerobic bacteria in food. Petrifilm was compared with a standard method in several different food products with satisfactory results. However, many studies showed that bacterial counts in Petrifilm were significantly lower than those obtained with conventional methods in fermented food. The purpose of this study was to compare the Petrifilm method for enumerating aerobic bacteria with a conventional method (PCA) in Crottin goat's cheese. Thirty samples were used for the colony count. The mean count and standard deviation were 7.18 +/- 1.17 log CFU g(-1) on PCA and 7.11 +/- 1.05 log CFU g(-1) on Petrifilm. Analysis of variance revealed no significant differences between both methods (t = 1.33, P = 0.193). The Pearson correlation coefficient (0.971, P = 0.0001) indicated a strong linear relationship between the Petrifilm and the standard method. The results showed that Petrifilm is suitable and a convenient alternative to this standard method for the enumeration of aerobic flora in goat soft cheese.

  1. [Role of lactic acid bacteria in the spread of antibiotic resistant bacteria among healthy persons].

    PubMed

    Zigangirova, N A; Tokarskaia, E A; Narodnitskiĭ, B S; Gintsburg, A L; Tugel'ian, V A

    2006-01-01

    The wide use of antibiotics in livestock raising has contributed to the selection and accumulation of representatives of commensal microflora, as well as pathogenic bacteria, colonizing livestock and poultry. For this reason the problem of the possible transfer of antibiotic-resistance genes along the chain from bacteria, autochthonous for agricultural animals, to bacteria used for the production of foodstuffs, which are incorporated into normal microflora and may thus participate in the exchange of these genes with bacteria, enteropathogenic for humans, is a highly important task of medical microbiology. The article deals with the review of experimental data, indicative the possibility of the appearance of antibiotic-resistant pathogenic bacteria due to the transfer of antibiotic-resistance genes via alimentary chains.

  2. Aerobic Anoxygenic Phototrophic Bacteria in the Mid-Atlantic Bight and the North Pacific Gyre. Revised

    NASA Technical Reports Server (NTRS)

    Cottrell, Matthew T.; Mannino, Antonio; Kirchman, David L.

    2005-01-01

    The abundance of aerobic anoxygenic phototrophic (AM) bacteria, cyanobacteria and heterotrophs was examined in the Mid-Atlantic Bight and the central North Pacific gyre using infrared fluorescence microscopy coupled with image analysis and flow cytometry. AAP bacteria comprised 5% to 16% of total prokaryotes in the Atlantic but only 5% or less in the Pacific. In the Atlantic, AAP bacterial abundance was as much as 2-fold higher than Prochlorococcus and 10-folder higher than Synechococcus. In contrast, Prochlorococcus outnumbered AAP bacteria 5- to 50-fold in the Pacific. In both oceans, subsurface abundance maxima occurred within the photic zone, and AAP bacteria were least abundant below the 1% light depth. Concentrations of bacteriochlorophyll a (BChl a) were low (approx.1%) compared to chlorophyll a. Although the BChl a content of AAP bacteria per cell was typically 20- to 250-fold lower than the divinyl-chlorophyll a content of Prochlorococcus, in shelf break water the pigment content of AAP bacteria approached that of Prochlorococcus. The abundance of AAP bacteria rivaled some groups of strictly heterotrophic bacteria and was often higher than the abundance of known AAP genera (Erythrobacter and Roseobacter spp.). The distribution of AAP bacteria in the water column, which was similar in the Atlantic and the Pacific, was consistent with phototrophy.

  3. Development of specific fluorescent oligonucleotide probes for in situ identification of wine lactic acid bacteria.

    PubMed

    Blasco, Lucía; Ferrer, Sergi; Pardo, Isabel

    2003-08-08

    A rapid method for the identification of lactic acid bacteria (LAB) from wine has been developed. This method is based on fluorescence in situ hybridisation (FISH), using fluorescent oligonucleotide probes, homologous to 16S rDNA of those species of LAB commonly found in wines. The protocol for the specific detection of these bacteria was established through the hybridisation of 36 reference strains. The specificity of the probes was evaluated by using pure cultures. Probes were used to identify species in different wines, making it evident that direct identification and quantification from natural samples without culturing is also possible. The results show that FISH is a promising technique for the rapid identification of LAB, allowing positive identification in a few hours (4-16 h).

  4. Behavior of Psychrotrophic Lactic Acid Bacteria Isolated from Spoiling Cooked Meat Products

    PubMed Central

    Hamasaki, Yoshikatsu; Ayaki, Mitsuko; Fuchu, Hidetaka; Sugiyama, Masaaki; Morita, Hidetoshi

    2003-01-01

    Three kinds of lactic acid bacteria were isolated from spoiling cooked meat products stored below 10°C. They were identified as Leuconostoc mesenteroides subsp. mesenteroides, Lactococcus lactis subsp. lactis, and Leuconostoc citreum. All three strains grew well in MRS broth at 10°C. In particular, L. mesenteroides subsp. mesenteroides and L. citreum grew even at 4°C, and their doubling times were 23.6 and 51.5 h, respectively. On the other hand, although the bacteria were initially below the detection limit (<10 CFU/g) in model cooked meat products, the bacterial counts increased to 108 CFU/g at 10°C after 7 to 12 days. PMID:12788779

  5. A method for the identification of proteins secreted by lactic acid bacteria grown in complex media.

    PubMed

    Sánchez, Borja; Chaignepain, Sthéphane; Schmitter, Jean-Marie; Urdaci, María C

    2009-06-01

    Lactic acid bacteria (LAB) are known for their special nutritional requirements, being usually cultured in complex media to achieve optimal growth. In this paper, a protocol based on trichloroacetic acid precipitation of peptides and proteins is presented. The method has been tested on four probiotic LAB strains grown in De Man Rogosa Sharpe (MRS) broth, a complex medium that is often used for the culture of such bacteria. This protocol allowed the detection of 19 proteins after sodium dodecyl sulfate-polyacrylamide gel electrophoresis, 10 of them being successfully identified by tandem MS. Thereafter, the 10 were found to be secreted or surface associated by bioinformatic means. In conclusion, this work supplies a method for the identification of proteins secreted by LAB, allowing discrimination between the proteins present in the MRS and those produced by probiotic LAB.

  6. Reporter systems for in vivo tracking of lactic acid bacteria in animal model studies

    PubMed Central

    van Zyl, Winschau F; Deane, Shelly M; Dicks, Leon M T

    2015-01-01

    Bioluminescence (BLI) and fluorescence imaging (FI) allow for non-invasive detection of viable microorganisms from within living tissue and are thus ideally suited for in vivo probiotic studies. Highly sensitive optical imaging techniques detect signals from the excitation of fluorescent proteins, or luciferase-catalyzed oxidation reactions. The excellent relation between microbial numbers and photon emission allow for quantification of tagged bacteria in vivo with extreme accuracy. More information is gained over a shorter period compared to traditional pre-clinical animal studies. The review summarizes the latest advances in in vivo bioluminescence and fluorescence imaging and points out the advantages and limitations of different techniques. The practical application of BLI and FI in the tracking of lactic acid bacteria in animal models is addressed. PMID:26516656

  7. Biotechnological and in situ food production of polyols by lactic acid bacteria.

    PubMed

    Ortiz, Maria Eugenia; Bleckwedel, Juliana; Raya, Raúl R; Mozzi, Fernanda

    2013-06-01

    Polyols such as mannitol, erythritol, sorbitol, and xylitol are naturally found in fruits and vegetables and are produced by certain bacteria, fungi, yeasts, and algae. These sugar alcohols are widely used in food and pharmaceutical industries and in medicine because of their interesting physicochemical properties. In the food industry, polyols are employed as natural sweeteners applicable in light and diabetic food products. In the last decade, biotechnological production of polyols by lactic acid bacteria (LAB) has been investigated as an alternative to their current industrial production. While heterofermentative LAB may naturally produce mannitol and erythritol under certain culture conditions, sorbitol and xylitol have been only synthesized through metabolic engineering processes. This review deals with the spontaneous formation of mannitol and erythritol in fermented foods and their biotechnological production by heterofermentative LAB and briefly presented the metabolic engineering processes applied for polyol formation.

  8. Novel bacteriocins from lactic acid bacteria (LAB): various structures and applications.

    PubMed

    Perez, Rodney H; Zendo, Takeshi; Sonomoto, Kenji

    2014-08-29

    Bacteriocins are heat-stable ribosomally synthesized antimicrobial peptides produced by various bacteria, including food-grade lactic acid bacteria (LAB). These antimicrobial peptides have huge potential as both food preservatives, and as next-generation antibiotics targeting the multiple-drug resistant pathogens. The increasing number of reports of new bacteriocins with unique properties indicates that there is still a lot to learn about this family of peptide antibiotics. In this review, we highlight our system of fast tracking the discovery of novel bacteriocins, belonging to different classes, and isolated from various sources. This system employs molecular mass analysis of supernatant from the candidate strain, coupled with a statistical analysis of their antimicrobial spectra that can even discriminate novel variants of known bacteriocins. This review also discusses current updates regarding the structural characterization, mode of antimicrobial action, and biosynthetic mechanisms of various novel bacteriocins. Future perspectives and potential applications of these novel bacteriocins are also discussed.

  9. Biopreservation of refrigerated and vacuum-packed Dicentrarchus labrax by lactic acid bacteria.

    PubMed

    El Bassi, Leila; Hassouna, Mnasser; Shinzato, Naoya; Matsui, Toru

    2009-08-01

    Two lactic acid bacteria (LAB) were selected from 100 LAB isolated from various sea products to examine their use in Dicentrarchus labrax preservation. The isolates, tentatively named strain nr 3 and 7, were identified as Lactobacillus plantarum and L. pentosus, respectively. They showed antagonistic activity against psychrotroph, pathogenic, and coliform bacteria. The antagonistic activity of strain 3 was suggested to be by bacteriocins since activity was abolished by protease treatment, while that of strain 7 was due to the effect of pH decrease caused by the produced organic acids. Their use prevented total volatile basic nitrogen contents (TVB-N) and trimethylamine (TMA) to some extent, suggesting that inoculation could extend the period of storage.

  10. Novel bacteriocins from lactic acid bacteria (LAB): various structures and applications

    PubMed Central

    2014-01-01

    Bacteriocins are heat-stable ribosomally synthesized antimicrobial peptides produced by various bacteria, including food-grade lactic acid bacteria (LAB). These antimicrobial peptides have huge potential as both food preservatives, and as next-generation antibiotics targeting the multiple-drug resistant pathogens. The increasing number of reports of new bacteriocins with unique properties indicates that there is still a lot to learn about this family of peptide antibiotics. In this review, we highlight our system of fast tracking the discovery of novel bacteriocins, belonging to different classes, and isolated from various sources. This system employs molecular mass analysis of supernatant from the candidate strain, coupled with a statistical analysis of their antimicrobial spectra that can even discriminate novel variants of known bacteriocins. This review also discusses current updates regarding the structural characterization, mode of antimicrobial action, and biosynthetic mechanisms of various novel bacteriocins. Future perspectives and potential applications of these novel bacteriocins are also discussed. PMID:25186038

  11. Natural populations of lactic acid bacteria isolated from vegetable residues and silage fermentation.

    PubMed

    Yang, J; Cao, Y; Cai, Y; Terada, F

    2010-07-01

    Natural populations of lactic acid bacteria (LAB) and silage fermentation of vegetable residues were studied. Fifty-two strains of LAB isolated from cabbage, Chinese cabbage, and lettuce residues were identified and characterized. The LAB strains were gram-positive and catalase-negative bacteria, which were divided into 6 groups (A to F) according to morphological and biochemical characteristics. The strains in group A were rods that did not produce gas from glucose and formed the d and l isomers of lactate. Groups B and C were homofermentative cocci that formed l-lactic acid. Groups D, E, and F were heterofermentative cocci that formed d-lactic acid. Based on 16S rDNA gene sequence analysis, group A to F strains were identified as Lactobacillus plantarum, Lactococcus piscium, Lactococcus lactis, Leuconostoc citreum, Weissella soli and Leuconostoc gelidum, respectively. The prevalent LAB, predominantly homofermentative lactobacilli, consisted of Lactobacillus plantarum (34.6%), Weissella soli (19.2%), Leuconostoc gelidum (15.4%), Leuconostoc citreum (13.5%), Lactococcus lactis (9.6%), and Lactococcus piscium (7.7%). Lactobacillus plantarum was the dominant member of the LAB population in 3 types of vegetable residues. These vegetable residues contained a high level of crude protein (20.2 to 28.4% of dry matter). These silages prepared by using a small-scale fermentation system were well preserved, with low pH and a relatively high content of lactate. This study suggests that the vegetable residues contain abundant LAB species and nutrients, and that they could be well preserved by making silage, which is a potentially good vegetable protein source for livestock diets.

  12. Phenolic acid degradation potential and growth behavior of lactic acid bacteria in sunflower substrates.

    PubMed

    Fritsch, Caroline; Heinrich, Veronika; Vogel, Rudi F; Toelstede, Simone

    2016-08-01

    Sunflower flour provides a high content of protein with a well-balanced amino acid composition and is therefore regarded as an attractive source for protein. The use for human nutrition is hindered by phenolic compounds, mainly chlorogenic acid, which can lead under specific circumstances to undesirable discolorations. In this study, growth behavior and degradation ability of chlorogenic acid of four lactic acid bacteria were explored. Data suggested that significant higher fermentation performances on sunflower flour as compared to sunflower protein concentrate were reached by Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus gasseri and Bifidobacterium animalis subsp. lactis. In fermentation with the latter two strains reduced amounts of chlorogenic acid were observed in sunflower flour (-11.4% and -19.8%, respectively), which were more pronounced in the protein concentrate (-50.7% and -95.6%, respectively). High tolerances against chlorogenic acid and the cleavage product quinic acid with a minimum inhibitory concentration (MIC) of ≥20.48 mg/ml after 48 h were recorded for all strains except Bifidobacterium animalis subsp. lactis, which was more sensitive. The second cleavage compound, caffeic acid revealed a higher antimicrobial potential with MIC values of 0.64-5.12 mg/ml. In this proof of concept study, degradation versus inhibitory effect suggest the existence of basic mechanisms of interaction between phenolic acids in sunflower and lactic acid bacteria and a feasible way to reduce the chlorogenic acid content, which may help to avoid undesired color changes.

  13. Honeybees and beehives are rich sources for fructophilic lactic acid bacteria.

    PubMed

    Endo, Akihito; Salminen, Seppo

    2013-09-01

    Fructophilic lactic acid bacteria (FLAB) are a specific group of lactic acid bacteria (LAB) characterized and described only recently. They prefer fructose as growth substrate and inhabit only fructose-rich niches. Honeybees are high-fructose-consuming insects and important pollinators in nature, but reported to be decreasing in the wild. In the present study, we analyzed FLAB microbiota in honeybees, larvae, fresh honey and bee pollen. A total of 66 strains of LAB were isolated from samples using a selective isolation technique for FLAB. Surprisingly, all strains showed fructophilic characteristics. The 66 strains and ten FLAB strains isolated from flowers in a separate study were genotypically separated into six groups, four of which being identified as Lactobacillus kunkeei and two as Fructobacillus fructosus. One of the L. kunkeei isolates showed antibacterial activity against Melissococcus plutonius, a causative pathogen of European foulbrood, this protection being attributable to production of an antibacterial peptide or protein. Culture-independent analysis suggested that bee products and larvae contained simple Lactobacillus-group microbiota, dominated by L. kunkeei, although adult bees carried a more complex microbiota. The findings clearly demonstrate that honeybees and their products are rich sources of FLAB, and FLAB are potential candidates for future bee probiotics.

  14. Lactic acid bacteria producing B-group vitamins: a great potential for functional cereals products.

    PubMed

    Capozzi, Vittorio; Russo, Pasquale; Dueñas, María Teresa; López, Paloma; Spano, Giuseppe

    2012-12-01

    Wheat contains various essential nutrients including the B group of vitamins. However, B group vitamins, normally present in cereals-derived products, are easily removed or destroyed during milling, food processing or cooking. Lactic acid bacteria (LAB) are widely used as starter cultures for the fermentation of a large variety of foods and can improve the safety, shelf life, nutritional value, flavor and overall quality of the fermented products. In this regard, the identification and application of strains delivering health-promoting compounds is a fascinating field. Besides their key role in food fermentations, several LAB found in the gastrointestinal tract of humans and animals are commercially used as probiotics and possess generally recognized as safe status. LAB are usually auxotrophic for several vitamins although certain strains of LAB have the capability to synthesize water-soluble vitamins such as those included in the B group. In recent years, a number of biotechnological processes have been explored to perform a more economical and sustainable vitamin production than that obtained via chemical synthesis. This review article will briefly report the current knowledge on lactic acid bacteria synthesis of vitamins B2, B11 and B12 and the potential strategies to increase B-group vitamin content in cereals-based products, where vitamins-producing LAB have been leading to the elaboration of novel fermented functional foods. In addition, the use of genetic strategies to increase vitamin production or to create novel vitamin-producing strains will be also discussed.

  15. Spherical Lactic Acid-producing Bacteria of Southern-grown Raw and Processed Vegetables

    PubMed Central

    Mundt, J. Orvin; Graham, Wanda F.; McCarty, I. E.

    1967-01-01

    The frequency and levels of population of the spherical lactic acid-producing bacteria were determined on raw and processed yellow summer and zucchini squash, a variety of greens, green beans, okra, southern peas, and butter and lima beans, and on fresh cucumbers and corn flowers. Six taxa occurred consistently: Leuconostoc mesenteroides, yellow-pigmented streptococci, Streptococcus faecium, Aerococcus viridans, and S. faecalis and S. faecalis var. liquefaciens. The same taxa occurred with the same order of frequency on processed, frozen vegetables, but with a marked decrease in the occurrence of S. faecalis var. liquefaciens. S. lactis, S. cremoris, S. equinus, S. bovis, and pediococci were isolated infrequently. No other member of the viridans group of the streptococci and no member of the pyogenic group was isolated. Approximately 88% of the cultures were identified. Total counts of the lactic-acid-producing bacteria rarely exceeded 105 per gram of sample, and there was a reduction by 90% during the second year of study, probably because of drought. Only one bacterial species was found on 40% of the raw and 34% of the processed vegetable samples. Two or more species or taxa were present on the remainder of 153 raw and 56 processed vegetable samples. A. viridans was present on squash, greens, okra, and southern peas, and its frequency of occurrence on vegetables suggests that plants are its natural habitat. PMID:16349739

  16. Prediction of acid lactic-bacteria growth in turkey ham processed by high hydrostatic pressure

    PubMed Central

    Mathias, S.P.; Rosenthal, A.; Gaspar, A.; Aragão, G.M.F.; Slongo-Marcusi, A.

    2013-01-01

    High hydrostatic pressure (HHP) has been investigated and industrially applied to extend shelf life of meat-based products. Traditional ham packaged under microaerophilic conditions may sometimes present high lactic acid bacteria population during refrigerated storage, which limits shelf life due to development of unpleasant odor and greenish and sticky appearance. This study aimed at evaluating the shelf life of turkey ham pressurized at 400 MPa for 15 min and stored at 4, 8 and 12 °C, in comparison to the non pressurized product. The lactic acid bacteria population up to 107 CFU/g of product was set as the criteria to determine the limiting shelf life According to such parameter the pressurized sample achieved a commercial viability within 75 days when stored at 4 °C while the control lasted only 45 days. Predictive microbiology using Gompertz and Baranyi and Roberts models fitted well both for the pressurized and control samples. The results indicated that the high hydrostatic pressure treatment greatly increased the turkey ham commercial viability in comparison to the usual length, by slowing down the growth of microorganisms in the product. PMID:24159279

  17. Improved screening procedure for biogenic amine production by lactic acid bacteria.

    PubMed

    Bover-Cid, S; Holzapfel, W H

    1999-12-01

    An improved screening plate method for the detection of amino acid decarboxylase-positive microorganisms (especially lactic acid bacteria) was developed. The suitability and detection level of the designed medium were quantitatively evaluated by confirmation of amine-forming capacity using an HPLC procedure. The potential to produce the biogenic amines (BA) tyramine, histamine, putrescine, and cadaverine, was investigated in a wide number of lactic acid bacteria (LAB) of different origin, including starter cultures, protective cultures, type strains and strains isolated from different food products. Also, several strains of Enterobacteriaceae were examined. Modifications to previously described methods included lowering glucose and sodium chloride concentrations, and increasing the buffer effect with calcium carbonate and potassium phosphate. In addition, pyridoxal-5-phosphate was included as a codecarboxylase factor for its enhancing effect on the amino acid decarboxylase activity. The screening plate method showed a good correlation with the chemical analysis and due to its simplicity it is presented as a suitable and sensitive method to investigate the capacity of biogenic amine production by LAB. Tyramine was the main amine formed by the LAB strains investigated. Enterococci, carnobacteria and some strains of lactobacilli, particularly of Lb. curvatus. Lb. brevis and Lb. buchneri, were the most intensive tyramine formers. Several strains of lactobacilli, Leuconostoc spp., Weissella spp. and pediococci did not show any potential to produce amines. Enterobacteriaceae were associated with cadaverine and putrescine formation. No significant histamine production could be detected for any of the strains tested.

  18. Identification of dairy lactic acid bacteria by tRNAAla-23S rDNA-RFLP.

    PubMed

    Mancini, Andrea; Lazzi, Camilla; Bernini, Valentina; Neviani, Erasmo; Gatti, Monica

    2012-12-01

    The aim of this study was to evaluate the potential of target tRNA(Ala)-23S ribosomal DNA for identification of lactic acid bacteria strains associated with dairy ecosystem. For this purpose tRNA(Ala)-23S ribosomal DNA Restriction Fragment Length Polymorphism (tRNA(Ala)-23S rDNA-RFLP) was compared with two widely used DNA fingerprinting methods - P1 Random Amplified Polymorphic DNA (RAPD), (GTG)5 repetitive extragenic palindromic PCR (rep-PCR) - for their ability to identify different species on a set of 10 type and 34 reference strains. Moreover, 75 unknown isolates collected during different stages of Grana Padano cheese production and ripening were identified using tRNA(Ala)-23S rDNA-RFLP and compared to the RFLP profiles of the strains in the reference database. This study demonstrated that the target tRNA(Ala)-23S rDNA has high potential in bacterial identification and tRNA(Ala)-23S rDNA-RFLP is a promising method for reliable species-level identification of lactic acid bacteria (LAB) in dairy products.

  19. Selected Lactic Acid Bacteria Synthesize Antioxidant Peptides during Sourdough Fermentation of Cereal Flours

    PubMed Central

    Coda, Rossana; Pinto, Daniela; Gobbetti, Marco

    2012-01-01

    A pool of selected lactic acid bacteria was used for the sourdough fermentation of various cereal flours with the aim of synthesizing antioxidant peptides. The radical-scavenging activity of water/salt-soluble extracts (WSE) from sourdoughs was significantly (P < 0.05) higher than that of chemically acidified doughs. The highest activity was found for whole wheat, spelt, rye, and kamut sourdoughs. Almost the same results were found for the inhibition of linoleic acid autoxidation. WSE were subjected to reverse-phase fast protein liquid chromatography. Thirty-seven fractions were collected and assayed in vitro. The most active fractions were resistant to further hydrolysis by digestive enzymes. Twenty-five peptides of 8 to 57 amino acid residues were identified by nano-liquid chromatography-electrospray ionization-tandem mass spectrometry. Almost all of the sequences shared compositional features which are typical of antioxidant peptides. All of the purified fractions showed ex vivo antioxidant activity on mouse fibroblasts artificially subjected to oxidative stress. This study demonstrates the capacity of sourdough lactic acid bacteria to release peptides with antioxidant activity through the proteolysis of native cereal proteins. PMID:22156436

  20. Improving the antioxidant properties of quinoa flour through fermentation with selected autochthonous lactic acid bacteria.

    PubMed

    Rizzello, Carlo Giuseppe; Lorusso, Anna; Russo, Vito; Pinto, Daniela; Marzani, Barbara; Gobbetti, Marco

    2017-01-16

    Lactic acid bacteria strains, previously isolated from the same matrix, were used to ferment quinoa flour aiming at exploiting the antioxidant potential. As in vitro determined on DPPH and ABTS radicals, the scavenging activity of water/salt-soluble extracts (WSE) from fermented doughs was significantly (P<0.05) higher than that of non-inoculated doughs. The highest inhibition of linoleic acid autoxidation was found for the quinoa dough fermented with Lactobacillus plantarum T0A10. The corresponding WSE was subjected to Reverse Phase Fast Protein Liquid Chromatography, and 32 fractions were collected and subjected to in vitro assays. The most active fraction was resistant to further hydrolysis by digestive enzymes. Five peptides, having sizes from 5 to 9 amino acid residues, were identified by nano-Liquid Chromatography-Electrospray Ionisation-Mass Spectra/Mass Spectra. The sequences shared compositional features which are typical of antioxidant peptides. As shown by determining cell viability and radical scavenging activity (MTT and DCFH-DA assays, respectively), the purified fraction showed antioxidant activity on human keratinocytes NCTC 2544 artificially subjected to oxidative stress. This study demonstrated the capacity of autochthonous lactic acid bacteria to release peptides with antioxidant activity through proteolysis of native quinoa proteins. Fermentation of the quinoa flour with a selected starter might be considered suitable for novel applications as functional food ingredient, dietary supplement or pharmaceutical preparations.

  1. Antioxidative activities of soymilk fermented with lactic acid bacteria and bifidobacteria.

    PubMed

    Wang, Yi-Chieh; Yu, Roch-Chui; Chou, Cheng-Chun

    2006-04-01

    To further the goal of developing a probiotic dietary adjunct using soymilk, soymilk is fermented with lactic acid bacteria (Lactobacillus acidophilus CCRC 14079 or Streptococcus thermophilus CCRC 14085) and bifidobacteria (Bifidobacterium infantis CCRC 14633 or Bifidobacterium longum B6) individually, and in conjunction. We investigate several antioxidative activities including the inhibition of ascorbate autoxidation, the scavenging effect of superoxide anion radicals and hydrogen peroxide, and the reducing activity exerted by different varieties of fermented soymilks. In addition, the effect of spray-drying and freeze-drying on changes in antioxidative activity is examined. We find that in fermented soymilk both the inhibition of ascorbate autoxidation, and the reducing activity and scavenging effect of superoxide anion radicals varied with the starters used, but nevertheless are significantly higher than those found in unfermented soymilk. In general, antioxidative activity in soymilk fermented with lactic acid bacteria and bifidobacteria simultaneously is significantly higher (P < 0.05) than that fermented with either individually. Moreover, antioxidative activity increases as the fermentation period is extended. However, unfermented soymilk shows an H2O2-scavenging effect, while there is no scavenging effect except for the accumulation of H2O2 in fermented soymilk. Finally, we find that freeze-drying causes a significantly lesser (P < 0.05) reduction in the antioxidative activity of soymilk than does spray-drying. Irrespective of the drying method and the starters used for fermentation. The antioxidative activity of fermented soymilk reduces after drying yet remains higher than that of dried unfermented soymilk.

  2. Diversity of lactic acid bacteria population in ripened Parmigiano Reggiano cheese.

    PubMed

    Gala, Elisabetta; Landi, Sara; Solieri, Lisa; Nocetti, Marco; Pulvirenti, Andrea; Giudici, Paolo

    2008-07-31

    The diversity of dominant lactic acid bacteria population in 12 months ripened Parmigiano Reggiano cheeses was investigated by a polyphasic approach including culture-dependent and independent methods. Traditional plating, isolation of LAB and identification by 16S rDNA analysis showed that strains belonging to Lactobacillus casei group were the most frequently isolated. Lactobacillus helveticus, Lactobacillus delbrueckii subsp. lactis, Lactobacillus parabuchneri, and Lactobacillus buchneri species were detected with lower frequency. PCR-denaturing gradient gel electrophoresis (DGGE) applied to DNA extracted directly from cheese samples and sequencing of rDNA amplicons confirmed the complex microbiological pattern of LAB in ripened Parmigiano Reggiano cheeses, with the significant exception of the Lactobacillus fermentum species, which dominated in several samples, but was not detected by cultivation. The present combination of different approaches can effectively describe the lactic acid bacteria population of Parmigiano Reggiano cheese in advanced stages of ripening, giving useful information for elucidating the role of LAB in determining the final cheese quality.

  3. Technological and functional applications of low-calorie sweeteners from lactic acid bacteria.

    PubMed

    Patra, F; Tomar, S K; Arora, S

    2009-01-01

    Lactic acid bacteria (LAB) have been extensively used for centuries as starter cultures to carry out food fermentations and are looked upon as burgeoning "cell factories" for production of host of functional biomolecules and food ingredients. Low-calorie sugars have been a recent addition and have attracted a great deal of interest of researchers, manufacturers, and consumers for varied reasons. These sweeteners also getting popularized as low-carb sugars have been granted generally recommended as safe (GRAS) status by the U.S. Federal Drug Administration (USFDA) and include both sugars and sugar alcohols (polyols) which in addition to their technological attributes (sugar replacer, bulking agent, texturiser, humectant, cryoprotectant) have been observed to exert a number of health benefits (low calories, low glycemic index, anticariogenic, osmotic diuretics, obesity control, prebiotic). Some of these sweeteners successfully produced by lactic acid bacteria include mannitol, sorbitol, tagatose, and trehalose and there is a potential to further enhance their production with the help of metabolic engineering. These safe sweeteners can be exploited as vital food ingredients for development of low-calorie foods with added functional values especially for children, diabetic patients, and weight watchers.

  4. Modelling and predicting the simultaneous growth of Escherichia coli and lactic acid bacteria in milk.

    PubMed

    Ačai, P; Valík, L'; Medved'ová, A; Rosskopf, F

    2016-09-01

    Modelling and predicting the simultaneous competitive growth of Escherichia coli and starter culture of lactic acid bacteria (Fresco 1010, Chr. Hansen, Hørsholm, Denmark) was studied in milk at different temperatures and Fresco inoculum concentrations. The lactic acid bacteria (LAB) were able to induce an early stationary state in E. coli The developed model described and tested the growth inhibition of E. coli (with initial inoculum concentration 10(3) CFU/mL) when LAB have reached maximum density in different conditions of temperature (ranging from 12 ℃ to 30 ℃) and for various inoculum sizes of LAB (ranging from approximately 10(3) to 10(7) CFU/mL). The prediction ability of the microbial competition model (the Baranyi and Roberts model coupled with the Gimenez and Dalgaard model) was first performed only with parameters estimated from individual growth of E. coli and the LAB and then with the introduced competition coefficients evaluated from co-culture growth of E. coli and LAB in milk. Both the results and their statistical indices showed that the model with incorporated average values of competition coefficients improved the prediction of E. coli behaviour in co-culture with LAB.

  5. Phylogenetically Diverse Aerobic Anoxygenic Phototrophic Bacteria Isolated from Epilithic Biofilms in Tama River, Japan

    PubMed Central

    Hirose, Setsuko; Matsuura, Katsumi; Haruta, Shin

    2016-01-01

    The diversity of aerobic anoxygenic phototrophic (AAP) bacteria in freshwater environments, particularly in rivers, has not been examined in as much detail as in ocean environments. In the present study, we investigated the phylogenetic and physiological diversities of AAP bacteria in biofilms that developed on submerged stones in a freshwater river using culture methods. The biofilms collected were homogenized and inoculated on solid media and incubated aerobically in the dark. Sixty-eight red-, pink-, yellow-, orange-, or brown-colored colonies were isolated, and, of these, 28 isolates contained the photosynthetic pigment, bacteriochlorophyll (BChl) a. Phylogenetic analyses based on 16S rRNA gene sequences showed that the isolates were classified into 14 groups in 8 operational taxonomic units (OTUs) and distributed in the orders Rhodospirillales, Rhodobacterales, and Sphingomonadales of Alphaproteobacteria and in Betaproteobacteria. Physiological analyses confirmed that none of the representative isolates from any of the groups grew under anaerobic phototrophic conditions. Seven isolates in 4 OTUs showed a 16S rRNA gene sequence identity of 98.0% or less with any established species, suggesting the presence of previously undescribed species of AAP bacteria. Six isolates in 2 other OTUs had the closest relatives, which have not been reported to be AAP bacteria. Physiological comparisons among the isolates revealed differences in preferences for nutrient concentrations, BChl contents, and light-harvesting proteins. These results suggest that diverse and previously unknown AAP bacteria inhabit river biofilms. PMID:27453124

  6. Efficacy of Locally Isolated Lactic Acid Bacteria Against Antibiotic-Resistant Uropathogens

    PubMed Central

    Manzoor, Asma; Ul-Haq, Ikram; Baig, Shahjhan; Qazi, Javed Iqbal; Seratlic, Sanja

    2016-01-01

    Background: Antibiotic resistance represents a serious global health threat to public health, so infections such as pneumonia and urinary tract infection (UTI) are becoming harder to treat. Therefore, it is necessary to develop an action plan to restrain the problem of antibiotic resistance. One approach in UTI control could be the use of lactobacilli because these indigenous inhabitants in human intestine have been found to play an important role in protecting the host from various infections. Objectives: We sought to check the efficacy of locally isolated Lactobacillus species to eradicate antibiotic-resistant pathogenic bacteria causing UTI. Materials and Methods: Lactic acid bacteria isolated from spoiled fruits and vegetables and grown in MRS medium were screened against multi-drug-resistant Candida albicans, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus fecalis. Results: Fifty-four lactic acid bacteria were isolated from spoiled fruits and vegetables, of which 11 Gram-positive and catalase-negative Lactobacillus isolates were identified by carbohydrate assimilation profiles as Lactobacillus acidophilus, L. paracasei, L. delbrueckii, L. casei, L. helveticus, L. brevis, L. salivarius, L. fermentum, L. rhamnosus, L. animalis, and L. plantarum. The latter organism had the highest abundance of all the samples, so its isolates were also verified through 16S rRNA gene sequencing. The isolated Lactobacilli were screened against multi-drug-resistant uropathogens, viz. C. albicans, P. aeruginosa, K. pneumoniae, E. fecalis, and E. coli. The growth inhibition zone (GIZ) was over 10 mm against all the uropathogenic test organisms, where L. fermentum and L. plantarum strains demonstrated remarkable inhibitory activities against E. coli and E. faecalis, with a GIZ up to 28 mm. The susceptibility test to 16 antibiotics showed multidrug resistance (3 to 5 antibiotics) among all the tested uropathogens. Conclusions: The obtained results

  7. Total mesophilic counts underestimate in many cases the contamination levels of psychrotrophic lactic acid bacteria (LAB) in chilled-stored food products at the end of their shelf-life.

    PubMed

    Pothakos, Vasileios; Samapundo, Simbarashe; Devlieghere, Frank

    2012-12-01

    The major objective of this study was to determine the role of psychrotrophic lactic acid bacteria (LAB) in spoilage-associated phenomena at the end of the shelf-life of 86 various packaged (air, vacuum, modified-atmosphere) chilled-stored retail food products. The current microbiological standards, which are largely based on the total viable mesophilic counts lack discriminatory capacity to detect psychrotrophic LAB. A comparison between the total viable counts on plates incubated at 30 °C (representing the mesophiles) and at 22 °C (indicating the psychrotrophs) for 86 food samples covering a wide range - ready-to-eat vegetable salads, fresh raw meat, cooked meat products and composite food - showed that a consistent underestimation of the microbial load occurs when the total aerobic mesophilic counts are used as a shelf-life parameter. In 38% of the samples, the psychrotrophic counts had significantly higher values (+0.5-3 log CFU/g) than the corresponding total aerobic mesophilic counts. A total of 154 lactic acid bacteria, which were unable to proliferate at 30 °C were isolated. In addition, a further 43 with a poor recovery at this temperature were also isolated. This study highlights the potential fallacy of the total aerobic mesophilic count as a reference shelf-life parameter for chilled food products as it can often underestimate the contamination levels at the end of the shelf-life.

  8. Anaerobic lactic acid degradation during ensilage of whole crop maize inoculated with lactobacillus buchneri inhibits yeast growth and improves aerobic stability

    PubMed

    Driehuis; Elferink; Spoelstra

    1999-10-01

    Aerobic deterioration of silages is initiated by (facultative) aerobic micro-organisms, usually yeasts, that oxidize the preserving organic acids. In this study, a Lactobacillus buchneri strain isolated from maize silage was evaluated for its potential as a bacterial inoculant that enhances aerobic stability of silages. In four experiments, chopped whole crop maize (30-43% dry matter (DM)) was inoculated with Lact. buchneri and ensiled in laboratory silos. Uninoculated silages served as controls. Analysis of silages treated with Lact. buchneri at levels of 103-106 cfu g-1 after about 3 months of anaerobic storage showedthat acetic acid and 1-propanol contents increased with inoculum levels above 104 cfu g-1,whereas lactic acid decreased. Propionic acid, silage pH and DM loss increased withinoculum levels above 105 cfu g-1. Time course experiments with maize inoculated with Lact. buchneri at 4 x 104-2 x 105 cfu g-1 showed that up to 7-14 d after ensiling, Lact. buchneri had no effect on silage characteristics. Thereafter, the lactic acid content of the inoculated silages declined and, simultaneously, acetic acid and, to a lesser extent, propionic acid and 1-propanol, accumulated. Inoculation reduced survival of yeasts during the anaerobic storage phase and inhibited yeast growth when the silage was exposed to O2, resulting in a substantial improvement in aerobic stability. The results indicate that the use of Lact. buchneri as a silage inoculant can enhance aerobic stability by inhibition of yeasts. The ability of the organism to ferment lactic acid to acetic acid appears to be an important underlying principle of this effect.

  9. Phytate degradation by lactic acid bacteria and yeasts during the wholemeal dough fermentation: a 31P NMR study.

    PubMed

    Reale, Anna; Mannina, Luisa; Tremonte, Patrizio; Sobolev, Anatoli P; Succi, Mariantonietta; Sorrentino, Elena; Coppola, Raffaele

    2004-10-06

    myo-Inositol hexaphosphate (IP6) is the main source of phosphorus in cereal grains, and therefore, in bakery products. Different microorganisms such as yeasts and lactic acid bacteria have phytase enzymes able to hydrolyze IP6 during the wholemeal breadmaking. In this paper, the phytase activity of Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus curvatus, and Saccharomyces cerevisiae strains, isolated from southern Italian sourdoughs, is assayed using the (31)P NMR technique. The sourdough technology based on the use of lactic acid bacteria in the breadmaking is finally suggested.

  10. High abundances of aerobic anoxygenic photosynthetic bacteria in the South Pacific Ocean.

    PubMed

    Lami, Raphaël; Cottrell, Matthew T; Ras, Joséphine; Ulloa, Osvaldo; Obernosterer, Ingrid; Claustre, Hervé; Kirchman, David L; Lebaron, Philippe

    2007-07-01

    Little is known about the abundance, distribution, and ecology of aerobic anoxygenic phototrophic (AAP) bacteria, particularly in oligotrophic environments, which represent 60% of the ocean. We investigated the abundance of AAP bacteria across the South Pacific Ocean, including the center of the gyre, the most oligotrophic water body of the world ocean. AAP bacteria, Prochlorococcus, and total prokaryotic abundances, as well as bacteriochlorophyll a (BChl a) and divinyl-chlorophyll a concentrations, were measured at several depths in the photic zone along a gradient of oligotrophic conditions. The abundances of AAP bacteria and Prochlorococcus were high, together accounting for up to 58% of the total prokaryotic community. The abundance of AAP bacteria alone was up to 1.94 x 10(5) cells ml(-1) and as high as 24% of the overall community. These measurements were consistent with the high BChl a concentrations (up to 3.32 x 10(-3) microg liter(-1)) found at all stations. However, the BChl a content per AAP bacterial cell was low, suggesting that AAP bacteria are mostly heterotrophic organisms. Interestingly, the biovolume and therefore biomass of AAP bacteria was on average twofold higher than that of other prokaryotic cells. This study demonstrates that AAP bacteria can be abundant in various oligotrophic conditions, including the most oligotrophic regime of the world ocean, and can account for a large part of the bacterioplanktonic carbon stock.

  11. Binary Interactions of Antagonistic Bacteria with Candida albicans Under Aerobic and Anaerobic Conditions.

    PubMed

    Benadé, Eliska; Stone, Wendy; Mouton, Marnel; Postma, Ferdinand; Wilsenach, Jac; Botha, Alfred

    2016-04-01

    We used both aerobic and anaerobic liquid co-cultures, prepared with Luria Bertani broth, to study the effect of bacteria on the survival of Candida albicans in the external environment, away from an animal host. The bacteria were represented by Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Clostridium, Enterobacter, Klebsiella pneumoniae, Kluyvera ascorbata and Serratia marcescens. Under aerobic conditions, the yeast's growth was inhibited in the presence of bacterial growth; however, under anaerobic conditions, yeast and bacterial growth in co-cultures was similar to that observed for pure cultures. Subsequent assays revealed that the majority of bacterial strains aerobically produced extracellular hydrolytic enzymes capable of yeast cell wall hydrolysis, including chitinases and mannan-degrading enzymes. In contrast, except for the A. hydrophila strain, these enzymes were not detected in anaerobic bacterial cultures, nor was the antimicrobial compound prodigiosin found in anaerobic cultures of S. marcescens. When we suspended C. albicans cells in crude extracellular enzyme preparations from K. pneumoniae and S. marcescens, we detected no negative effect on yeast viability. However, we found that these preparations enhance the toxicity of prodigiosin towards the yeast, especially in combination with mannan-degrading enzymes. Analyses of the chitin and mannan content of yeast cell walls revealed that less chitin was produced under anaerobic than aerobic conditions; however, the levels of mannan, known for its low permeability, remained the same. The latter phenomenon, as well as reduced production of the bacterial enzymes and prodigiosin, may contribute to anaerobic growth and survival of C. albicans in the presence of bacteria.

  12. Preservation of acidified cucumbers with a natural preservative combination of fumaric acid and allyl isothiocyanate that target lactic acid bacteria and yeasts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Without the addition of preservative compounds cucumbers acidified with 150 mM acetic acid with pH adjusted to 3.5 typically undergo fermentation by lactic acid bacteria. Fumaric acid (20 mM) inhibited growth of Lactobacillus plantarum and the lactic acid bacteria present on fresh cucumbers, but sp...

  13. Isolation, characterisation and identification of lactic acid bacteria from bushera: a Ugandan traditional fermented beverage.

    PubMed

    Muyanja, C M B K; Narvhus, J A; Treimo, J; Langsrud, T

    2003-02-15

    One hundred and thirteen strains of lactic acid bacteria (LAB) were selected from 351 isolates from 15 samples of traditionally fermented household bushera from Uganda and also from laboratory-prepared bushera. Isolates were phenotypically characterised by their ability to ferment 49 carbohydrates using API 50 CHL kits and additional biochemical tests. Coliforms, yeasts and LAB were enumerated in bushera. The pH, volatile organic compounds and organic acids were also determined. The LAB counts in household bushera varied between 7.1 and 9.4 log cfu ml(-1). The coliform counts varied between < 1 and 5.2 log cfu ml(-1). The pH of bushera ranged from 3.7 to 4.5. Ethanol (max, 0.27%) was the major volatile organic compound while lactic acid (max, 0.52%) was identified as the dominant organic acid in household bushera. The initial numbers of LAB and coliforms in laboratory-fermented bushera were similar; however, the LAB numbers increased faster during the first 24 h. LAB counts increased from 5.5 to 9.0 log cfu ml(-1) during the laboratory fermentation. Coliform counts increased from 5.9 to 7.8 log cfu ml(-1) at 24 h, but after 48 h, counts were less 4 log cfu ml(-1). Yeasts increased from 4.3 to 7.7 log cfu ml(-1) at 48 h, but thereafter decreased slightly. The pH declined from 7.0 to around 4.0. Lactic acid and ethanol increased from zero to 0.75% and 0.20%, respectively. Lactic acid bacteria isolated from household bushera belonged to Lactobacillus, Streptococcus and Enterococcus genera. Tentatively, Lactobacillus isolates were identified as Lactobacillus plantarum, L. paracasei subsp. paracasei, L. fermentum, L. brevis and L. delbrueckii subsp. delbrueckii. Streptococcus thermophilus strains were also identified in household bushera. LAB isolated from bushera produced in the laboratory belonged to five genera (Lactococcus, Leuconostoc, Lactobacillus, Weissella and Enterococcus. Eight isolates were able to produce acid from starch and were identified as Lactococcus

  14. Role of specific components from commercial inactive dry yeast winemaking preparations on the growth of wine lactic acid bacteria.

    PubMed

    Andújar-Ortiz, Inmaculada; Pozo-Bayón, Maria Angeles; García-Ruiz, Almudena; Moreno-Arribas, M Victoria

    2010-07-28

    The role of specific components from inactive dry yeast preparations widely used in winemaking on the growth of three representative wine lactic acid bacteria (Oenococcus oeni, Lactobacillus hilgardii and Pediococcus pentosaceus) has been studied. A pressure liquid extraction technique using solvents of different polarity was employed to obtain extracts with different chemical composition from the inactive dry yeast preparations. Each of the extracts was assayed against the three lactic acid bacteria. Important differences in the effect of the extracts on the growth of the bacteria were observed, which depended on the solvent employed during the extraction, on the type of commercial preparations and on the lactic acid bacteria species. The extracts that exhibited the most different activity were chemically characterized in amino acids, free monosaccharides, monosaccharides from polysaccharides, fatty acids and volatile compounds. In general, specific amino acids and monosaccharides were related to a stimulating effect whereas fatty acid composition and likely some volatile compounds seemed to show an inhibitory effect on the growth of the lactic acid bacteria. These results may provide novel and useful information in trying to obtain better and more specific formulations of winemaking inactive dry yeast preparations.

  15. The Occurrence of Beer Spoilage Lactic Acid Bacteria in Craft Beer Production.

    PubMed

    Garofalo, Cristiana; Osimani, Andrea; Milanović, Vesna; Taccari, Manuela; Aquilanti, Lucia; Clementi, Francesca

    2015-12-01

    Beer is one of the world's most ancient and widely consumed fermented alcoholic beverages produced with water, malted cereal grains (generally barley and wheat), hops, and yeast. Beer is considered an unfavorable substrate of growth for many microorganisms, however, there are a limited number of bacteria and yeasts, which are capable of growth and may spoil beer especially if it is not pasteurized or sterile-filtered as craft beer. The aim of this research study was to track beer spoilage lactic acid bacteria (LAB) inside a brewery and during the craft beer production process. To that end, indoor air and work surface samples, collected in the brewery under study, together with commercial active dry yeasts, exhausted yeasts, yeast pellet (obtained after mature beer centrifugation), and spoiled beers were analyzed through culture-dependent methods and PCR-DGGE in order to identify the contaminant LAB species and the source of contamination. Lactobacillus brevis was detected in a spoiled beer and in a commercial active dry yeast. Other LAB species and bacteria ascribed to Staphylococcus sp., Enterobaceriaceae, and Acetobacter sp. were found in the brewery. In conclusion, the PCR-DGGE technique coupled with the culture-dependent method was found to be a useful tool for identifying the beer spoilage bacteria and the source of contamination. The analyses carried out on raw materials, by-products, final products, and the brewery were useful for implementing a sanitization plan to be adopted in the production plant.

  16. Current status and emerging role of glutathione in food grade lactic acid bacteria

    PubMed Central

    2012-01-01

    Lactic acid bacteria (LAB) have taken centre stage in perspectives of modern fermented food industry and probiotic based therapeutics. These bacteria encounter various stress conditions during industrial processing or in the gastrointestinal environment. Such conditions are overcome by complex molecular assemblies capable of synthesizing and/or metabolizing molecules that play a specific role in stress adaptation. Thiols are important class of molecules which contribute towards stress management in cell. Glutathione, a low molecular weight thiol antioxidant distributed widely in eukaryotes and Gram negative organisms, is present sporadically in Gram positive bacteria. However, new insights on its occurrence and role in the latter group are coming to light. Some LAB and closely related Gram positive organisms are proposed to possess glutathione synthesis and/or utilization machinery. Also, supplementation of glutathione in food grade LAB is gaining attention for its role in stress protection and as a nutrient and sulfur source. Owing to the immense benefits of glutathione, its release by probiotic bacteria could also find important applications in health improvement. This review presents our current understanding about the status of glutathione and its role as an exogenously added molecule in food grade LAB and closely related organisms. PMID:22920585

  17. Dual-coated lactic acid bacteria: an emerging innovative technology in the field of probiotics.

    PubMed

    Alvarez-Calatayud, Guillermo; Margolles, Abelardo

    2016-01-01

    Probiotics are living micro-organisms that do not naturally have shelf life, and normally are weakly protected against the digestive action of the GI tract. A new dual coating technology has been developed in an effort to maximize survival, that is, to be able to reach the intestine alive and in sufficient numbers to confer the beneficial health effects on the host. Dual-coating of lactic acid bacteria (LAB) is the result of fourth-generation coating technology for the protection of these bacteria at least 100-fold or greater than the uncoated LAB. This innovative technique involves a first pH-dependent protein layer that protects bacteria from gastric acid and bile salt, and a second polysaccharide matrix that protects bacteria from external factors, such as humidity, temperature and pressure, as well as the digestive action during the passage through the GI tract. Dual-coated probiotic formulation is applicable to different therapeutic areas, including irritable bowel syndrome, atopic dermatitis, acute diarrhea, chronic constipation, Helicobacter pylori eradication, and prevention of antibiotic-associated diarrhea. An updated review of the efficacy of doubly coated probiotic strains for improving bacterial survival in the intestinal tract and its consequent clinical benefits in humans is here presented.

  18. Extracellular protease derived from lactic acid bacteria stimulates the fermentative lactic acid production from the by-products of rice as a biomass refinery function.

    PubMed

    Watanabe, Masanori; Techapun, Charin; Kuntiya, Ampin; Leksawasdi, Noppol; Seesuriyachan, Phisit; Chaiyaso, Thanongsak; Takenaka, Shinji; Maeda, Isamu; Koyama, Masahiro; Nakamura, Kozo

    2017-02-01

    A lactic acid producing bacterium, Lactobacillus rhamnosus M-23, newly isolated from a rice washing drainage storage tank was found to produce l-(+)-lactic acid from a non-sterilized mixture of rice washing drainage and rice bran without any additions of nutrients under the simultaneous saccharification and fermentation (SSF) process. This strain has the ability to utilize the non-sterilized rice washing drainage and rice bran as a source of carbohydrate, saccharifying enzymes and nutrients for lactic acid production. Observation of extracellular protease activity in SSF culture broth showed that a higher protease activity was present in strain M-23 than in other isolated lactic acid producing bacteria (LABs). To investigate the structural changes of solid particles of rice washing drainage throughout LAB cultivation, scanning electron microscopic (SEM) observation and Fourier transform infrared-spectroscopy (FT-IR) analysis were performed. The results of the SEM observation showed that the surface material could be removed from solid particles of rice washing drainage treated by culture broth (supernatant) of strain M-23, thus exposing the crystal structure of the starch particle surface. The results of the FT-IR analysis revealed that the specific transmittance decrease of the CC and CO stretching and OH group of the solid particles of the rice washing drainage were highly correlated with the produced lactic acid concentration and extracellular protease activity, respectively. These results demonstrate the high lactic acid producing ability of strain M-23 from a non-sterilized mixture of rice washing drainage and rice bran under the SSF condition due to the removal of proteinaceous material and exposure of the starch particle surface by extracellular protease.

  19. Isolation and characterization of lactic acid bacteria strains with ornithine producing capacity from natural sea salt.

    PubMed

    Yu, Jin-Ju; Oh, Suk-Heung

    2010-08-01

    Two lactic acid bacteria (LAB) having ornithine-producing capacity were isolated from Korean natural sea salt. They were Gram-positive, short rod-type bacteria, and able to grow anaerobically with CO(2) production. The isolates grew well on MRS broth at 30-37 degrees C and a pH of 6.5-8.0. The optimum temperature and pH for growth are 37 degrees C and pH 7.0. The isolates fermented D-ribose, D-galactose, D-lactose, D-maltose, Dcellobiose, D-tagatose, D-trehalose, sucrose, D-melezitose, gentiobiose, D-glucose but not D-melibiose, inositol, and L-sorbose. The 16S rDNA sequences of the two isolates showed 99.5% and 99.6% homology with the Weissella koreensis S5623 16S rDNA (Access no. AY035891). They were accordingly identified and named as Weissella koreensis MS1-3 and Weissella koreensis MS1-14, and produced intracellular ornithine at levels of 72 mg/100 g cell F.W. and 105 mg/100 g cell F.W. and extracellular ornithine at levels of 4.5 mg/100 ml and 4.6 mg/100 ml medium, respectively, by culturing in MRS broth supplemented with 1% arginine. High cell growth was maintained in MRS broth with a NaCl concentration of 0-6%. These results show for the first time that Korean natural sea salts contain lactic acid bacteria Weissella koreensis strains having ornithine producing capacity.

  20. Identification and quantification of antifungal compounds produced by lactic acid bacteria and propionibacteria.

    PubMed

    Le Lay, Céline; Coton, Emmanuel; Le Blay, Gwenaëlle; Chobert, Jean-Marc; Haertlé, Thomas; Choiset, Yvan; Van Long, Nicolas Nguyen; Meslet-Cladière, Laurence; Mounier, Jérôme

    2016-12-19

    Fungal growth in bakery products represents the most frequent cause of spoilage and leads to economic losses for industrials and consumers. Bacteria, such as lactic acid bacteria and propionibacteria, are commonly known to play an active role in preservation of fermented food, producing a large range of antifungal metabolites. In a previous study (Le Lay et al., 2016), an extensive screening performed both in vitro and in situ allowed for the selection of bacteria exhibiting an antifungal activity. In the present study, active supernatants against Penicillium corylophilum and Aspergillus niger were analyzed to identify and quantify the antifungal compounds associated with the observed activity. Supernatant treatments (pH neutralization, heating and addition of proteinase K) suggested that organic acids played the most important role in the antifungal activity of each tested supernatant. Different methods (HPLC, mass spectrometry, colorimetric and enzymatic assays) were then applied to analyze the supernatants and it was shown that the main antifungal compounds corresponded to lactic, acetic and propionic acids, ethanol and hydrogen peroxide, as well as other compounds present at low levels such as phenyllactic, hydroxyphenyllactic, azelaic and caproic acids. Based on these results, various combinations of the identified compounds were used to evaluate their effect on conidial germination and fungal growth of P. corylophilum and Eurotium repens. Some combinations presented the same activity than the bacterial culture supernatant thus confirming the involvement of the identified molecules in the antifungal activity. The obtained results suggested that acetic acid was mainly responsible for the antifungal activity against P. corylophilum and played an important role in E. repens inhibition.

  1. Dietary hyperoxaluria is not reduced by treatment with lactic acid bacteria

    PubMed Central

    2013-01-01

    Background Secondary hyperoxaluria either based on increased intestinal absorption of oxalate (enteric), or high oxalate intake (dietary), is a major risk factor of calcium oxalate urolithiasis. Oxalate-degrading bacteria might have beneficial effects on urinary oxalate excretion resulting from decreased intestinal oxalate concentration and absorption. Methods Twenty healthy subjects were studied initially while consuming a diet normal in oxalate. Study participants were then placed on a controlled oxalate-rich diet for a period of 6 weeks. Starting with week 2 of the oxalate-rich diet, participants received 2.6 g/day of a lactic acid bacteria preparation for 5 weeks. Finally, subjects were examined 4 weeks after treatment while consuming again a normal-oxalate diet. Participants provided weekly 24-hour urine specimens. Analyses of blood samples were performed before and at the end of treatment. Results Urinary oxalate excretion increased significantly from 0.354 ± 0.097 at baseline to 0.542 ± 0.163 mmol/24 h under the oxalate-rich diet and remained elevated until the end of treatment, as did relative supersaturation of calcium oxalate. Plasma oxalate concentration was significantly higher after 5 weeks of treatment compared to baseline. Four weeks after treatment, urinary oxalate excretion and relative supersaturation of calcium oxalate fell to reach initial values. Conclusions Persistent dietary hyperoxaluria and increased plasma oxalate concentration can already be induced in healthy subjects without disorders of oxalate metabolism. The study preparation neither reduced urinary oxalate excretion nor plasma oxalate concentration. The preparation may be altered to select for lactic acid bacteria strains with the highest oxalate-degrading activity. PMID:24330782

  2. Characterization, identification and application of lactic Acid bacteria isolated from forage paddy rice silage.

    PubMed

    Ni, Kuikui; Wang, Yanping; Li, Dongxia; Cai, Yimin; Pang, Huili

    2015-01-01

    There has been growing interest to develop forage rice as a new feed resource for livestock. This study was to characterize the natural population of lactic acid bacteria (LAB) and select potentially excellent strains for paddy rice silage preparation in China. One hundred and twenty-six strains were isolated and screened from paddy rice silage prepared using a small-scale fermentation system, and ninety-nine of these isolates were considered to be LAB based on their Gram-positive and catalase-negative morphology and the production of most of their metabolic products as lactic acid. These isolates were divided into eight groups (A-H) on the basis of their morphological and biochemical characteristics. The Group A to H strains were identified as Lactobacillus (L.) plantarum subsp. plantarum (species ratio: 8.1%), L. casei (5.1%), Leuconostoc (Ln.) pseudomesenteroides (11.1%), Pediococcus (P.) pentosaceus (24.2%), Enterococcus (E.) mundtii (12.1%), Lactococcus (Lc.) garvieae (15.2%), E. faecium (9.1%) and Lc. lactis subsp. lactis (15.2%) based on sequence analyses of their 16S rRNA and recA genes. P. pentosaceus was the most abundant member of the LAB population in the paddy rice silage. A selected strain, namely L. casei R 465, was found to be able to grow under low pH conditions and to improve the silage quality with low pH and a relatively high content of lactic acid. This study demonstrated that forage paddy rice silage contains abundant LAB species and its silage can be well preserved by inoculation with LAB, and that strain R 465 can be a potentially excellent inoculant for paddy rice silage.

  3. Isolating and evaluating lactic acid bacteria strains for effectiveness of Leymus chinensis silage fermentation.

    PubMed

    Zhang, Q; Li, X J; Zhao, M M; Yu, Z

    2014-10-01

    Five LAB strains were evaluated using the acid production ability test, morphological observation, Gram staining, physiological, biochemical and acid tolerance tests. All five strains (LP1, LP2, LP3, LC1 and LC2) grew at pH 4·0, and LP1 grew at 15°C. Strains LP1, LP2 and LP3 were identified as Lactobacillus plantarum, whereas LC1 and LC2 were classified as Lactobacillus casei by sequencing 16S rDNA. The five isolated strains and two commercial inoculants (PS and CL) were added to native grass and Leymus chinensis (Trin.) Tzvel. for ensiling. All five isolated strains decreased the pH and ammonia nitrogen content, increased the lactic acid content and LP1, LP2 and LP3 increased the acetic content and lactic/acetic acid ratio of L. chinensis silage significantly. The five isolated strains and two commercial inoculants decreased the butyric acid content of the native grass silage. LP2 treatment had lower butyric acid content and ammonia nitrogen content than the other treatments. The five isolated strains improved the quality of L. chinensis silage. The five isolated strains and the two commercial inoculants were not effective in improving the fermentation quality of the native grass silage, but LP2 performed better comparatively. Significance and impact of the study: Leymus chinensis is an important grass in China and Russia, being the primary grass of the short grassland 'steppe' regions of central Asia. However, it has been difficult to make high-quality silage of this species because of low concentration of water-soluble carbohydrates (WSC). Isolating and evaluating lactic acid bacteria strains will be helpful for improving the silage quality of this extensively grown species.

  4. Characterization, Identification and Application of Lactic Acid Bacteria Isolated from Forage Paddy Rice Silage

    PubMed Central

    Ni, Kuikui; Wang, Yanping; Li, Dongxia; Cai, Yimin; Pang, Huili

    2015-01-01

    There has been growing interest to develop forage rice as a new feed resource for livestock. This study was to characterize the natural population of lactic acid bacteria (LAB) and select potentially excellent strains for paddy rice silage preparation in China. One hundred and twenty-six strains were isolated and screened from paddy rice silage prepared using a small-scale fermentation system, and ninety-nine of these isolates were considered to be LAB based on their Gram-positive and catalase-negative morphology and the production of most of their metabolic products as lactic acid. These isolates were divided into eight groups (A-H) on the basis of their morphological and biochemical characteristics. The Group A to H strains were identified as Lactobacillus (L.) plantarum subsp. plantarum (species ratio: 8.1%), L. casei (5.1%), Leuconostoc (Ln.) pseudomesenteroides (11.1%), Pediococcus (P.) pentosaceus (24.2%), Enterococcus (E.) mundtii (12.1%), Lactococcus (Lc.) garvieae (15.2%), E. faecium (9.1%) and Lc. lactis subsp. lactis (15.2%) based on sequence analyses of their 16S rRNA and recA genes. P. pentosaceus was the most abundant member of the LAB population in the paddy rice silage. A selected strain, namely L. casei R 465, was found to be able to grow under low pH conditions and to improve the silage quality with low pH and a relatively high content of lactic acid. This study demonstrated that forage paddy rice silage contains abundant LAB species and its silage can be well preserved by inoculation with LAB, and that strain R 465 can be a potentially excellent inoculant for paddy rice silage. PMID:25803578

  5. Inhibition of Escherichia coli O157:H7 and Salmonella enterica on spinach and identification of antimicrobial substances produced by a commercial Lactic Acid Bacteria food safety intervention.

    PubMed

    Cálix-Lara, Thelma F; Rajendran, Mahitha; Talcott, Stephen T; Smith, Stephen B; Miller, Rhonda K; Castillo, Alejandro; Sturino, Joseph M; Taylor, T Matthew

    2014-04-01

    The microbiological safety of fresh produce is of concern for the U.S. food supply. Members of the Lactic Acid Bacteria (LAB) have been reported to antagonize pathogens by competing for nutrients and by secretion of substances with antimicrobial activity, including organic acids, peroxides, and antimicrobial polypeptides. The objectives of this research were to: (i) determine the capacity of a commercial LAB food antimicrobial to inhibit Escherichia coli O157:H7 and Salmonella enterica on spinach leaf surfaces, and (ii) identify antimicrobial substances produced in vitro by the LAB comprising the food antimicrobial. Pathogens were inoculated on freshly harvested spinach, followed by application of the LAB antimicrobial. Treated spinach was aerobically incubated up to 12 days at 7 °C and surviving pathogens enumerated via selective/differential plating. l-Lactic acid and a bacteriocin-like inhibitory substance (BLIS) were detected and quantified from cell-free fermentates obtained from LAB-inoculated liquid microbiological medium. Application of 8.0 log10 CFU/g LAB produced significant (p < 0.05) reductions in E. coli O157:H7 and Salmonella populations on spinach of 1.6 and 1.9 log10 CFU/g, respectively. It was concluded the LAB antimicrobial inhibited foodborne pathogens on spinach during refrigerated storage, likely the result of the production of metabolites with antimicrobial activity.

  6. Survival of anaerobic and aerobic bacteria in a nonsupportive gassed transport system.

    PubMed Central

    Chow, A W; Cunningham, P J; Guze, L B

    1976-01-01

    Survival of anaerobic and aerobic bacteria in a commercially available, non-supportive, gassed (oxygen-free) transport container (Anaport) was evaluated quantitatively. Saline-suspended obligate anaerobes survived significantly better in the gassed container in aerobic control tubes (P less than 0.025, t test), and counts were virtually unchanged after 8 h of holding. Similarly, initial counts and relative proportions of a mixture of Bacteroides fragilis and Staphylococcus aureus were maintained for 72 h. The value of the gassed transport system was less apparent when microorganisms were suspended in nutrient broth. The major advantage of the gassed transport system appears to be for holding of specimens collected by saline irrigation. PMID:1254710

  7. Lactic acid bacteria in Hamei and Marcha of North East India.

    PubMed

    Tamang, J P; Dewan, S; Tamang, B; Rai, A; Schillinger, U; Holzapfel, W H

    2007-06-01

    Hamei and Marcha are mixed dough inocula used as starters for preparation of various indigenous alcoholic beverages in Manipur and Sikkim in India, respectively. These starters are traditionally prepared from rice with wild herbs and spices. Samples of Hamei and Marcha, collected from Manipur and Sikkim, respectively, were analysed for lactic acid bacterial composition. The population of lactic acid bacteria (LAB) was 6.9 and 7.1 Log cfu/g in Hamei and Marcha, respectively. On the basis of phenotypic and genotypic characters, LAB strains isolated from Hamei and Marcha were identified as Pediococcus pentosaceus, Lactobacillus plantarum and Lactobacillus brevis. Technological properties of LAB such as antimicrobial properties, effect on acidification, ability to produce biogenic amines and ethanol, degree of hydrophobicity and enzymatic activities were also performed. Pediococcus pentosaceus HS: B1, isolated from Hamei, was found to produce bacteriocin. None of the strains produced biogenic amines. LAB strains showed a strong acidifying ability and they also produced a wide spectrum of enzymes.

  8. Screening, selection and characterization of phytic acid degrading lactic acid bacteria from chicken intestine.

    PubMed

    Raghavendra, Ponnala; Halami, Prakash M

    2009-07-31

    This study was undertaken to screen and select potent phytate degrading lactic acid bacteria and to evaluate their additional characteristic features. Forty lactic acid bacterial strains were isolated from different sources and screened for their ability to degrade myo-inositol hexaphosphate or IP(6) by cobalt chloride staining (plate assay) method, using calcium or sodium salt of phytic acid as substrate. All the forty isolates were able to degrade calcium phytate. However, only two Pediococcus pentosaceus strains (CFR R38 and CFR R35) were found to degrade sodium phytate. These strains showed phytase activity of 213 and 89 U at 50 degrees C, respectively and poor acid phosphatase activity. These strains were further evaluated for additional characteristic features. At pH 2, P. pentosaceus strains CFR R38 and CFR R35 showed 50.7 and 48.5 percentage survivability after 2 h of incubation respectively and they could also withstand 0.3% ox-bile. These cultures exhibited 54.6 and 44.8% of hydrophobicity to xylene, antibacterial activity against food borne pathogens and possessed beta-galactosidase activity. The resistance pattern to several antibiotics was also analyzed. The present study indicates that these strains, having phytate degrading ability and other characteristic features can be exploited as starter cultures in fermented foods to improve the mineral bioavailability.

  9. Use of virginiamycin to control the growth of lactic acid bacteria during alcohol fermentation.

    PubMed

    Hynes, S H; Kjarsgaard, D M; Thomas, K C; Ingledew, W M

    1997-04-01

    The antibiotic virginiamycin was investigated for its effects on growth and lactic acid production by seven strains of lactobacilli during the alcoholic fermentation of wheat mash by yeast. The lowest concentration of virginiamycin tested (0.5 mg Lactrol kg-1 mash), was effective against most of the lactic acid bacteria under study, but Lactobacillus plantarum was not significantly inhibited at this concentration. The use of virginiamycin prevented or reduced potential yield losses of up to 11% of the produced ethanol due to the growth and metabolism of lactobacilli. However, when the same concentration of virginiamycin was added to mash not inoculated with yeast, Lactobacillus rhamnosus and L. paracasei grew after an extensive lag of 48 h and L. plantarum grew after a similar lag even in the presence of 2 mg virginiamycin kg-1 mash. Results showed a variation in sensitivity to virginiamycin between the different strains tested and also a possible reduction in effectiveness of virginiamycin over prolonged incubation in wheat mash, especially in the absence of yeast.

  10. The rapid identification of lactic acid bacteria present in Chilean winemaking processes using culture-independent analysis.

    PubMed

    Ilabaca, Carolina; Jara, Carla; Romero, Jaime

    2014-01-01

    A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of 16S ribosomal RNA (rRNA) genes was developed to identify lactic acid bacteria (LAB) that are commonly present in winemaking processes (Oenococcus, Pediococcus, Lactobacillus, and Leuconostoc). This culture-independent approach revealed the presence of Oenococcus in the spontaneous malolactic fermentation in industrial Chilean wines.

  11. Dynamics of lactic acid bacteria populations in Rioja wines by PCR-DGGE, comparison with culture-dependent methods.

    PubMed

    González-Arenzana, Lucía; López, Rosa; Santamaría, Pilar; López-Alfaro, Isabel

    2013-08-01

    Lactic acid bacteria populations of red wine samples from industrial fermentations, including two different vinification methods were studied. For this investigation, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis was employed to supplement previous results that were obtained by culture-dependent methods. PCR-DGGE was aimed to study two targeted genes, 16S ribosomal DNA (rDNA) and rpoB, and the results were useful to evaluate the microbial populations in wine samples. Moreover, an improvement of a detection limit determined so far for DGGE analysis was obtained with the method described in this study, what made possible to identify lactic acid bacteria populations below 10(1) colony-forming unit/mL. The species Oenococcus oeni was the most frequently detected bacterium, but identifications close to species Oenococcus kitaharae and Lactococcus lactis that are not often found in wine were firstly identified in samples of this research. PCR-DGGE allowed to detect 9 out of 11 lactic acid bacteria species identified in this study (nine by PCR-16S rDNA/DGGE and four by PCR-rpoB/DGGE), while five species were detected using the modified de Man, Rogosa and Sharpe agar. Therefore, the two methods were demonstrated to be complementary. This finding suggests that analysis of the lactic acid bacteria population structure in wine should be carried out using both culture-dependent and culture-independent techniques with more than one primer pair.

  12. Preservation of acidified cucumbers with a combination of fumaric acid and cinnamaldehyde that target lactic acid bacteria and yeasts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The naturally occurring compound, fumaric acid, was evaluated as a potential preservative for the long-term storage of cucumbers. Fumaric acid inhibited growth of lactic acid bacteria (LAB) in an acidified cucumber juice medium model system resembling conditions that could allow preservation of cucu...

  13. Production of γ-Amino Butyric Acid in Tea Leaves wit Treatment of Lactic Acid Bacteria

    NASA Astrophysics Data System (ADS)

    Watanabe, Yuko; Hayakawa, Kiyoshi; Ueno, Hiroshi

    Lactic acid bacteria was searched for producing termented tea that contained a lot of γ-amino butyric acid(GABA). Also examined were the growth condition, GABA production and changes in catechin contents in the tea leaves. Lactobacillus brevis L12 was found to be suitable for the production of fermented tea since it gave as much GABA as gabaron tea when tea leaves being suspended with water at 10% and incubated for 4 days at 25°C. The amount of GABA produced was more than calculated based upon the content of glutamic acid in tea leaves. It is probable to assume that glutamate derived from glutamine and theanine is converted into GABA.

  14. Interaction between lactic acid bacteria and yeasts in sour-dough using a rheofermentometer.

    PubMed

    Gobbetti, M; Corsetti, A; Rossi, J

    1995-11-01

    Rheofermentometer assays were used to characterize the leavening of sour-doughs produced using species of lactic acid bacteria (LAB) and yeasts, alone or in combination. Saccharomyces cerevisiae 141 produced the most CO2 and ethanol whereas S. exiguus M14 and Lactobacillus brevis subsp. lindneri CB1 contributed poorly to leavening and gave sour-doughs without porosity. In comparison with that seen in sour-dough produced with yeast alone, yeast fermentation with heterofermentative LAB present was faster whereas that with homofermentative LAB (L. plantarum DC400, L. farciminis CF3) present was slower and produced more CO2. Combining L. brevis subsp. lindneri CB1 with S. cerevisiae 141 decreased bacterial cell numbers and souring activity. However, addition of fructose to the sour-dough overcame these problems as well as activating S. cerevisiae 141.

  15. Evaluation of the probiotic characteristics of newly isolated lactic acid bacteria.

    PubMed

    Aswathy, Ravindran Girija; Ismail, Bindhumol; John, Rojan Pappy; Nampoothiri, Kesavan Madhavan

    2008-12-01

    Lactic acid bacteria were isolated from fermented vegetables, sour dough, milk products, sheep and human excreta. The newly isolated cultures were evaluated for a number of probiotic characteristics like bile salt resistance, salt tolerance in general, survival in low pH, hydrophobicity of the cell surface, resistance to low phenol concentration, antimicrobial activity and susceptibility pattern against vancomycin and erythromycin. The selected cultures were further screened for their ability to produce the nutraceticals such as folic acid and exopolysaccharide (EPS). Two potent isolates, CB2 (from cabbage) and SD2 (from sour dough) were found to produce both extracellular and intracellular folate. One of the isolates from yogurt (MC-1) and the one from whey (W3) produced significant amount of EPS with a maximum production of 8.79 +/- 0.05 g/l by MC-1.

  16. Traditional Indian fermented foods: a rich source of lactic acid bacteria.

    PubMed

    Satish Kumar, R; Kanmani, P; Yuvaraj, N; Paari, K A; Pattukumar, V; Arul, V

    2013-06-01

    This review describes the diversity of Indian fermented food and its significance as a potential source of lactic acid bacteria (LAB). Fermented foods consumed in India are categorized based upon their base material. Fermented foods such as dahi, gundruk, sinki, iniziangsang, iromba, fermented rai, kanjika and handua were reported to have significant medicinal properties. Some fermented products such as koozh, dahi and kanjika are consumed unknowingly as, probiotic drinks, by local people. There are very few reports regarding isolation of LAB from Indian fermented foods available in the past; however, due to growing consciousness about potential health benefits of LAB, we now have scores of reports in this field. There is an abundant opportunity available for food microbiologists to explore the Indian fermented foods for the isolation of new LAB strains for their potential role in probiotic research.

  17. Growth inhibition of lactic acid bacteria in ham by nisin: a model approach.

    PubMed

    Kalschne, Daneysa L; Geitenes, Simone; Veit, Marilei R; Sarmento, Cleonice M P; Colla, Eliane

    2014-12-01

    Lactic acid bacteria (LAB) have been described as spoilage organisms in vacuum-packed cooked ham. A Fractional Factorial Design was performed to investigate the relative merits of sodium chloride, sodium lactate, sodium tripolyphosphate, sodium erythorbate, nisin and pediocin, in limiting the Lactobacillus sakei growth in broth culture. This allowed rejection of sodium chloride, sodium lactate and sodium erythorbate (no significant effects on growth), and a Central Composite Rotatable Design broth culture study was performed comparing the effects of nisin and pediocin. From this study, nisin was identified as a more important variable for inclusion into a cooked ham model (significant effects on growth parameters: logarithmic increase in the population, exponential microbial growth rate and lag phase extension). The validation of this outcome in a model formulation of vacuum-packed sliced cooked ham (0.001%, 0.007% and 0.013% of nisin) stored for 60days, confirmed the inhibitory effect of nisin on total LAB growth.

  18. Putrescine production from different amino acid precursors by lactic acid bacteria from wine and cider.

    PubMed

    Costantini, Antonella; Pietroniro, Roberta; Doria, Francesca; Pessione, Enrica; Garcia-Moruno, Emilia

    2013-07-01

    The aim of this work was to study the production of biogenic amines and particularly putrescine in lactic acid bacteria (LAB) related to wine and cider. We applied an analytical protocol that involves the use of PCR and TLC techniques to determine the production of putrescine from different precursors. Moreover, we also studied the ability of the Lactobacillus and Pediococcus tested to produce histamine and tyramine. The results showed that the majority of the Lactobacillus brevis analyzed harbour both AgDI and tdc genes and are tyramine and putrescine producers. Conversely, among the other LAB tested, only one Lactobacillus hilgardii and one Pediococcus pentosaceus produced putrescine. The AgDI gene was also detected in two other LAB (Lactobacillus mali and Pediococcus parvulus), but no putrescine production was observed. Finally, hdc gene and histamine production were found in strains (L. hilgardii 5211, isolated from wine, and Lactobacillus casei 18, isolated from cider) that were not putrescine producers.

  19. Medical and Personal Care Applications of Bacteriocins Produced by Lactic Acid Bacteria

    NASA Astrophysics Data System (ADS)

    Dicks, L. M. T.; Heunis, T. D. J.; van Staden, D. A.; Brand, A.; Noll, K. Sutyak; Chikindas, M. L.

    The frequent use of antibiotics has led to a crisis in the antibiotic ­resistance of pathogens associated with humans and animals. Antibiotic resistance and the emergence of multiresistant bacterial pathogens have led to the investigation of alternative antimicrobial agents to treat and prevent infections in both humans and animals. Research on antimicrobial peptides, with a special interest on bacteriocins of lactic acid bacteria, is entering a new era with novel applications other than food preservation. Many scientists are now focusing on the application of these peptides in medicinal and personal care products. However, it is difficult to assess the success of such ventures due to the dearth of information that has been published and the lack of clinical trials.

  20. Perspectives on the probiotic potential of lactic acid bacteria from African traditional fermented foods and beverages

    PubMed Central

    Mokoena, Mduduzi Paul; Mutanda, Taurai; Olaniran, Ademola O.

    2016-01-01

    Diverse African traditional fermented foods and beverages, produced using different types of fermentation, have been used since antiquity because of their numerous nutritional values. Lactic acid bacteria (LAB) isolated from these products have emerged as a welcome source of antimicrobials and therapeutics, and are accepted as probiotics. Probiotics are defined as live microbial food supplements which beneficially affect the host by improving the intestinal microbial balance. Currently, popular probiotics are derived from fermented milk products. However, with the growing number of consumers with lactose intolerance that are affected by dietary cholesterol from milk products, there is a growing global interest in probiotics from other food sources. The focus of this review is to provide an overview of recent developments on the applications of probiotic LAB globally, and to specifically highlight the suitability of African fermented foods and beverages as a viable source of novel probiotics. PMID:26960543

  1. Detection of arc genes related with the ethyl carbamate precursors in wine lactic acid bacteria.

    PubMed

    Araque, Isabel; Gil, Joana; Carreté, Ramon; Bordons, Albert; Reguant, Cristina

    2009-03-11

    Trace amounts of the carcinogen ethyl carbamate can appear in wine by the reaction of ethanol with compounds such as citrulline and carbamyl phosphate, which are produced from arginine degradation by some wine lactic acid bacteria (LAB). In this work, the presence of arc genes for the arginine-deiminase pathway was studied in several strains of different species of LAB. Their ability to degrade arginine was also studied. To detect the presence of arc genes, degenerate primers were designed from the alignment of protein sequences in already sequenced LAB. The usefulness of these degenerate primers has been proven by sequencing some of the amplified PCR fragments and searching for homologies with published sequences of the same species and related ones. Correlation was found between the presence of genes and the ability to degrade arginine. Degrading strains included all heterofermentative lactobacilli, Oenococcus oeni , Pediococcus pentosaceus , and some strains of Leuconostoc mesenteroides and Lactobacillus plantarum .

  2. Improvement of Intestinal Immune Cell Function by Lactic Acid Bacteria for Dairy Products

    PubMed Central

    Kamiya, Tomonori; Watanabe, Yohei; Makino, Seiya; Kano, Hiroshi; Tsuji, Noriko M

    2016-01-01

    Lactic acid bacteria (LAB) form a major component of gut microbiota and are often used as probiotics for fermented foods, such as yoghurt. In this study, we aimed to evaluate immunomodulatory activity of LAB, especially that of Lactobacillus bulgaricus ME-552 (ME552) and Streptococcus thermophilus ME-553 (ME553). In vivo/in vitro assay was performed in order to investigate their effects on T cell function. After oral administration of ME553 to C57BL/6 mice, the amount of both interferon γ (IFN-γ) and interleukin 17 (IL-17) produced by cluster of differentiation (CD) 4+ T cells from Peyer’s patches (PPs) were significantly enhanced. On the other hand, ME552 only up-regulated the production of IL-17 from PP cells. The extent of induction for IFN-γ production differed between ME552 and ME553. These results suggest that LAB modulate T cell effector functions and mucosal immunity. PMID:28025548

  3. Perspectives on the probiotic potential of lactic acid bacteria from African traditional fermented foods and beverages.

    PubMed

    Mokoena, Mduduzi Paul; Mutanda, Taurai; Olaniran, Ademola O

    2016-01-01

    Diverse African traditional fermented foods and beverages, produced using different types of fermentation, have been used since antiquity because of their numerous nutritional values. Lactic acid bacteria (LAB) isolated from these products have emerged as a welcome source of antimicrobials and therapeutics, and are accepted as probiotics. Probiotics are defined as live microbial food supplements which beneficially affect the host by improving the intestinal microbial balance. Currently, popular probiotics are derived from fermented milk products. However, with the growing number of consumers with lactose intolerance that are affected by dietary cholesterol from milk products, there is a growing global interest in probiotics from other food sources. The focus of this review is to provide an overview of recent developments on the applications of probiotic LAB globally, and to specifically highlight the suitability of African fermented foods and beverages as a viable source of novel probiotics.

  4. Inhibition of mycotoxin-producing Aspergillus nomius vsc 23 by lactic acid bacteria and Saccharomyces cerevisiae

    PubMed Central

    Muñoz, R; Arena, M.E.; Silva, J.; González, S.N.

    2010-01-01

    The effect of different fermenting microorganisms on growth of a mycotoxin- producing Aspergillus nomius was assayed. Two lactic acid bacteria, Lactobacillus fermentum and Lactobacillus rhamnosus, and Saccharomyces cerevisiae, all of which are widely used in fermentation and preservation of food, were assayed on their fungus inhibitory properties. Assays were carried out by simultaneous inoculation of one of the possible inhibiting microorganisms and the fungus or subsequent inoculation of one of the microorganisms followed by the fungus. All three microorganisms assayed showed growth inhibition of the mycotoxin-producing Aspergillus strain. L. rhamnosus O236, isolated from sheep milk and selected for its technological properties, showed highest fungal inhibition of the microorganisms assayed. The use of antifungal LAB with excellent technological properties rather than chemical preservatives would enable the food industry to produce organic food without addition of chemical substances. PMID:24031582

  5. Production, properties, and industrial food application of lactic acid bacteria-derived exopolysaccharides.

    PubMed

    Zannini, Emanuele; Waters, Deborah M; Coffey, Aidan; Arendt, Elke K

    2016-02-01

    Exopolysaccharides (EPS)-producing lactic acid bacteria (LAB) are industrially important microorganisms in the development of functional food products and are used as starter cultures or coadjutants to develop fermented foods. There is large variability in EPS production by LAB in terms of chemical composition, quantity, molecular size, charge, presence of side chains, and rigidity of the molecules. The main body of the review will cover practical aspects concerning the structural diversity structure of EPS, and their concrete application in food industries is reported in details. To strengthen the food application and process feasibility of LAB EPS at industrial level, a future academic research should be combined with industrial input to understand the technical shortfalls that EPS can address.

  6. Lactic acid bacteria associated with the digestive tract of Atlantic salmon (Salmo salar L.).

    PubMed

    Ringø, E; Bendiksen, H R; Wesmajervi, M S; Olsen, R E; Jansen, P A; Mikkelsen, H

    2000-08-01

    The present study reports the effect of excessive handling stress and starvation on the lactic acid bacteria associated with the digestive tract of Atlantic salmon (Salmo salar L.). A relatively low population level (approximately 2 x 103 bacteria per gram wet tissue) of viable adherent heterotrophic bacteria was associated with the digestive tract (foregut, midgut and hindgut). Of the 752 bacterial isolates isolated from diet, water and the digestive tract, 201 isolates belonged to the carnobacteria. Of these isolates, one from the diet, one from the rearing water and 80 from the gastrointestinal tract, were further identified on the basis of 16S rDNA sequence analysis. All these isolates were identified as being Carnobacterium piscicola-like. Daily repeated stress and starvation of the fish over 11 d had no influence on the total culturable bacterial numbers or population level of C. piscicola associated with the digestive tract. C. piscicola-like isolates colonizing the various intestinal regions (foregut, midgut and hindgut) were also screened for their ability to produce growth inhibitory compounds active against the fish pathogen Aeromonas salmonicida. Of the 199 C. piscicola isolates tested, 139 inhibited growth of the pathogen.

  7. In vitro screening of probiotic lactic acid bacteria and prebiotic glucooligosaccharides to select effective synbiotics.

    PubMed

    Grimoud, Julien; Durand, Henri; Courtin, Céline; Monsan, Pierre; Ouarné, Françoise; Theodorou, Vassilia; Roques, Christine

    2010-10-01

    Probiotics and prebiotics have been demonstrated to positively modulate the intestinal microflora and could promote host health. Although some studies have been performed on combinations of probiotics and prebiotics, constituting synbiotics, results on the synergistic effects tend to be discordant in the published works. The first aim of our study was to screen some lactic acid bacteria on the basis of probiotic characteristics (resistance to intestinal conditions, inhibition of pathogenic strains). Bifidobacterium was the most resistant genus whereas Lactobacillus farciminis was strongly inhibited. The inhibitory effect on pathogen growth was strain dependent but lactobacilli were the most effective, especially L. farciminis. The second aim of the work was to select glucooligosaccharides for their ability to support the growth of the probiotics tested. We demonstrated the selective fermentability of oligodextran and oligoalternan by probiotic bacteria, especially the bifidobacteria, for shorter degrees of polymerisation and absence of metabolism by pathogenic bacteria. Thus, the observed characteristics confer potential prebiotic properties on these glucooligosaccharides, to be further confirmed in vivo, and suggest some possible applications in synbiotic combinations with the selected probiotics. Furthermore, the distinctive patterns of the different genera suggest a combination of lactobacilli and bifidobacteria with complementary probiotic effects in addition to the prebiotic ones. These associations should be further evaluated for their synbiotic effects through in vitro and in vivo models.

  8. Identification of TLR2/TLR6 signalling lactic acid bacteria for supporting immune regulation

    PubMed Central

    Ren, Chengcheng; Zhang, Qiuxiang; de Haan, Bart J.; Zhang, Hao; Faas, Marijke M.; de Vos, Paul

    2016-01-01

    Although many lactic acid bacteria (LAB) influence the consumer’s immune status it is not completely understood how this is established. Bacteria-host interactions between bacterial cell-wall components and toll-like receptors (TLRs) have been suggested to play an essential role. Here we investigated the interaction between LABs with reported health effects and TLRs. By using cell-lines expressing single or combination of TLRs, we show that LABs can signal via TLR-dependent and independent pathways. The strains only stimulated and did not inhibit TLRs. We found that several strains such as L. plantarum CCFM634, L. plantarum CCFM734, L. fermentum CCFM381, L. acidophilus CCFM137, and S. thermophilus CCFM218 stimulated TLR2/TLR6. TLR2/TLR6 is essential in immune regulatory processes and of interest for prevention of diseases. Specificity of the TLR2/TLR6 stimulation was confirmed with blocking antibodies. Immunomodulatory properties of LABs were also studied by assessing IL-10 and IL-6 secretion patterns in bacteria-stimulated THP1-derived macrophages, which confirmed species and strain specific effects of the LABs. With this study we provide novel insight in LAB specific host-microbe interactions. Our data demonstrates that interactions between pattern recognition receptors such as TLRs is species and strain specific and underpins the importance of selecting specific strains for promoting specific health effects. PMID:27708357

  9. Characterization of some bacteriocins produced by lactic acid bacteria isolated from fermented foods.

    PubMed

    Grosu-Tudor, Silvia-Simona; Stancu, Mihaela-Marilena; Pelinescu, Diana; Zamfir, Medana

    2014-09-01

    Lactic acid bacteria (LAB) isolated from different sources (dairy products, fruits, fresh and fermented vegetables, fermented cereals) were screened for antimicrobial activity against other bacteria, including potential pathogens and food spoiling bacteria. Six strains have been shown to produce bacteriocins: Lactococcus lactis 19.3, Lactobacillus plantarum 26.1, Enterococcus durans 41.2, isolated from dairy products and Lactobacillus amylolyticus P40 and P50, and Lactobacillus oris P49, isolated from bors. Among the six bacteriocins, there were both heat stable, low molecular mass polypeptides, with a broad inhibitory spectrum, probably belonging to class II bacteriocins, and heat labile, high molecular mass proteins, with a very narrow inhibitory spectrum, most probably belonging to class III bacteriocins. A synergistic effect of some bacteriocins mixtures was observed. We can conclude that fermented foods are still important sources of new functional LAB. Among the six characterized bacteriocins, there might be some novel compounds with interesting features. Moreover, the bacteriocin-producing strains isolated in our study may find applications as protective cultures.

  10. Acute oral toxicity and bacterial translocation studies on potentially probiotic strains of lactic acid bacteria.

    PubMed

    Zhou, J S; Shu, Q; Rutherfurd, K J; Prasad, J; Gopal, P K; Gill, H S

    2000-01-01

    Three potentially probiotic lactic acid bacteria (LAB) strains, Lactobacillus rhamnosus HN001 (DR20(TM)), Lb. acidophilus HN017 and Bifidobacterium lactis HN019 (DR10()), have recently been identified and characterized. The present study was designed to evaluate the acute oral toxicity of these strains to mice, and also to investigate bacterial translocation and gut mucosal pathology in BALB/c mice fed HN019, HN001 or HN017 for 8 consecutive days at a high dose of 10(11)cfu/mouse/day. Results showed that these probiotic strains had no adverse effect on general health status, feed intake, body weight gain and intestinal mucosal morphology (villus height, crypt depth, epithelial cell height and mucosal thickness). No viable bacteria were recovered from blood and tissue samples (mesenteric lymph nodes, liver and spleen) of mice, and no treatment-associated illness or death was observed. According to these results, the oral LD(50) of HN019, HN001 and HN017 is more than 50g/kg/day for mice, and their acceptable daily intake (ADI) value is 35g dry bacteria per day for a 70-kg person. This suggests that the probiotic strains HN019, HN001 and HN017 are non-pathogenic and likely to be safe for human consumption.

  11. Efficacy of microencapsulated lactic acid bacteria in Helicobater pylori eradication therapy

    PubMed Central

    Khalil, Maha A.; El-Sheekh, Mostafa M.; El-Adawi, Hala I.; El-Deeb, Nehal M.; Hussein, Mohamed Z.

    2015-01-01

    Background: Probiotic delivery systems are widely used nutraceutical products for the supplementation of natural intestinal flora. These delivery systems vary greatly in the effectiveness to exert health benefits for a patient. This study focuses on providing probiotic living cells with a physical barrier against adverse environmental conditions. Materials and Methods: Microencapsulation of the selected lactic acid bacteria (LAB) using chitosan and alginate was performed. Physical examination of the formulated LAB microcapsules was observed using phase contrast inverted microscope and scanning electron microscope (SEM). Finally, the survival of microencapsulated and noncapsulated bacteria was cheeked in the simulated human gastric tract (GT). The potential antimicrobial activity of the most potent microencapsulated LAB strain was in vivo evaluated in rabbit models. Results: Microencapsulated L. plantarum, L. acidophilus, and L. bulgaricus DSMZ 20080 were loaded with 1.03 × 1010 CFU viable bacteria/g, 1.9 × 1010 CFU viable bacteria/g, and 5.5 × 109 CFU viable bacteria/g, respectively. The survival of microencapsulated cells was significantly higher than that of the free cells after exposure to simulated gastric juice (SGJ) at pH 2. Additionally, in simulated small intestine juice (SSJ), larger amounts of the selected LAB cells were found, whereas in simulated colon juice (SCJ), the released LAB reached the maximum counts. In vivo results pointed out that an 8-week supplementation with a triple therapy of a microencapsulated L. plantarum, L. acidophilus, and L. bulgaricus DSMZ 20080 might be able to reduce H. pylori. Conclusion: Microencapsulated probiotics could possibly compete with and downregulate H. pylori infection in humans. PMID:26929759

  12. Recent investigations and updated criteria for the assessment of antibiotic resistance in food lactic acid bacteria.

    PubMed

    Clementi, Francesca; Aquilanti, Lucia

    2011-12-01

    The worldwide use, and misuse, of antibiotics for about sixty years in the so-called antibiotic era, has been estimated in some one to ten million tons, a relevant part of which destined for non-therapeutic purposes such as growth promoting treatments for livestock or crop protection. As highly adaptable organisms, bacteria have reacted to this dramatic change in their environment by developing several well-known mechanisms of antibiotic resistance and are becoming increasingly resistant to conventional antibiotics. In recent years, commensal bacteria have become a cause of concern since they may act as reservoirs for the antibiotic resistance genes found in human pathogens. In particular, the food chain has been considered the main route for the introduction of animal and environment associated antibiotic resistant bacteria into the human gastrointestinal tract (GIT) where these genes may be transferred to pathogenic and opportunistic bacteria. As fundamental microbial communities in a large variety of fermented foods and feed, the anaerobe facultative, aerotolerant lactic acid bacteria (LAB) are likely to play a pivotal role in the resistance gene exchange occurring in the environment, food, feed and animal and human GIT. Therefore their antibiotic resistance features and their genetic basis have recently received increasing attention. The present article summarises the results of the latest studies on the most typical genera belonging to the low G + C branch of LAB. The evolution of the criteria established by European regulatory bodies to ensure a safe use of microorganisms in food and feed, including the assessment of their antibiotic resistance is also reviewed.

  13. Recovery of anaerobic, facultative, and aerobic bacteria from clinical specimens in three anaerobic transport systems.

    PubMed

    Helstad, A G; Kimball, J L; Maki, D G

    1977-06-01

    With aspirated specimens from clinical infections, we evaluated the recovery of anaerobic, aerobic, and facultative bacteria in three widely used transport systems: (i) aspirated fluid in a gassed-out tube (FGT), (ii) swab in modified Cary and Blair transport medium (SCB), and (iii) swab in a gassed-out tube (SGT). Transport tubes were held at 25 degrees C and semiquantitatively sampled at 0, 2, 24, and 48 h. Twenty-five clinical specimens yielded 75 anaerobic strains and 43 isolates of facultative and 3 of aerobic bacteria. Only one anaerobic isolate was not recovered in the first 24 h, and then, only in the SGT. At 48 h, 73 anaerobic strains (97%) were recovered in the FGT, 69 (92%) in the SCB, and 64 (85%) in the SGT. Two problems hindered the recovery of anaerobes in the SCB and SGT systems: first die-off of organisms, as evidenced by a decrease in colony-forming units of 20 strains (27%) in the SCB and 25 strains (33%) in the SGT, as compared with 7 strains (9%) in the FGT, over 48 h; and second, overgrowth of facultative bacteria, more frequent with SCB and SGT. The FGT method was clearly superior at 48 h to the SCB and SGT systems in this study and is recommended as the preferred method for transporting specimens for anaerobic culture.

  14. Aerobic Mercury-resistant bacteria alter Mercury speciation and retention in the Tagus Estuary (Portugal).

    PubMed

    Figueiredo, Neusa L; Canário, João; O'Driscoll, Nelson J; Duarte, Aida; Carvalho, Cristina

    2016-02-01

    Aerobic mercury-resistant bacteria were isolated from the sediments of two highly mercury-polluted areas of the Tagus Estuary (Barreiro and Cala do Norte) and one natural reserve area (Alcochete) in order to test their capacity to transform mercury. Bacterial species were identified using 16S rRNA amplification and sequencing techniques and the results indicate the prevalence of Bacillus sp. Resistance patterns to mercurial compounds were established by the determination of minimal inhibitory concentrations. Representative Hg-resistant bacteria were further tested for transformation pathways (reduction, volatilization and methylation) in cultures containing mercury chloride. Bacterial Hg-methylation was carried out by Vibrio fluvialis, Bacillus megaterium and Serratia marcescens that transformed 2-8% of total mercury into methylmercury in 48h. In addition, most of the HgR bacterial isolates showed Hg(2+)-reduction andHg(0)-volatilization resulting 6-50% mercury loss from the culture media. In summary, the results obtained under controlled laboratory conditions indicate that aerobic Hg-resistant bacteria from the Tagus Estuary significantly affect both the methylation and reduction of mercury and may have a dual face by providing a pathway for pollution dispersion while forming methylmercury, which is highly toxic for living organisms.

  15. A combination of lactic acid bacteria regulates Escherichia coli infection and inflammation of the bovine endometrium.

    PubMed

    Genís, Sandra; Sánchez-Chardi, Alejandro; Bach, Àlex; Fàbregas, Francesc; Arís, Anna

    2017-01-01

    Uterine function in cattle is compromised by bacterial contamination and inflammation after calving. The objective of this study was to select a combination of lactic acid bacteria (LAB) to decrease endometrium inflammation and Escherichia coli infection. Primary endometrial epithelial cells were cultured in vitro to select the most favorable LAB combination modulating basal tissue inflammation and E. coli infection. Supernatants were obtained to determine expression of pro-inflammatory cytokines, and E. coli infection was evaluated after harvesting the tissue and plate counting. The selected LAB combination was tested in uterus explants to assess its capacity to modulate basal and acute inflammation (associated with E. coli infection). The combination of Lactobacillus rhamnosus, Pediococcus acidilactici, and Lactobacillus reuteri at a ratio of 25:25:2, respectively, reduced E. coli infection in vitro with (89.77%) or without basal tissue inflammation (95.10%) compared with single LAB strains. Lactic acid bacteria treatment reduced CXCL8 and IL1B expression 4.7- and 2.2-fold, respectively, under acute inflammation. Ex vivo, the tested LAB combination reduced acute inflammation under E. coli infection, decreasing IL-8, IL-1β, and IL-6 up to 2.2-, 2.5-, and 2.2-fold, respectively. In the total inflammation model, the LAB combination decreased IL-8 1.6-fold and IL-6 1.2-fold. Ultrastructural evaluation of the tissue suggested no direct interaction between the LAB and E. coli, although pathological effects of E. coli in endometrial cells were greatly diminished or even reversed by the LAB combination. This study shows the promising potential of LAB probiotics for therapeutic use against endometrial inflammation and infection.

  16. Phytate degrading activities of lactic acid bacteria isolated from traditional fermented food

    NASA Astrophysics Data System (ADS)

    Damayanti, Ema; Ratisiwi, Febiyani Ndaru; Istiqomah, Lusty; Sembiring, Langkah; Febrisiantosa, Andi

    2017-03-01

    The objective of this study was to determine the potential of LAB with phytate degrading activity from fermented traditional food grain-based and legume-based. Lactic acid bacteria were isolated from different sources of traditional fermented food from Gunungkidul Yogyakarta Indonesia such as gembus tempeh (tofu waste), soybean tempeh, lamtoro tempeh (Leucaena bean) and kara tempeh. Isolation of LAB was performed using Total Plate Count (TPC) on de Man Rogosa Sharpe Agar (MRSA) medium supplemented with CaCO3. They were screened for their ability to degrade myo-inositol hexaphosphate or IP6 by using qualitative streak platemethod with modified de Man Rogosa-MorpholinoPropanesulfonic Acid Sharpe (MRS-MOPS) medium contained sodium salt of phytic acid as substrate and cobalt chloride staining (plate assay) method. The selected isolates were further assayed for phytase activities using quantitative method with spectrophotometer and the two selected isolates growth were optimized. Furthermore, thhe isolates that shown the highest phytase activity was characterized and identified using API 50 CH kitand 16S rRNA gene sequencing. The results showed that there were 18 LAB isolates obtained from samplesand 13 isolates were able to degrade sodium phytate based on qualitative screening. According to quantitative assay, the highest phytate degrading activities were found in TG-2(23.562 U/mL) and TG-1 (19.641 U/mL) isolated from gembus tempeh. The phytate activity of TG-2 was optimum at 37 °C with agitation, while the phytate activity of TG-1 was optimum at 45 °C without agitation. Characterization and identification of TG-2 isolate with the highest phytate degrading activity using API 50 CH and 16S rRNA showed that TG-2had homology with Lactobacillus fermentum. It could be concluded that LAB from from fermented traditional food grain-based and legume-based produced the extracellular phytase. Keywords: lactic acid bacteria, tempeh, phytatedegrading activity

  17. EFFECT OF POLYAMINE STRUCTURE ON GROWTH STIMULATION AND SPERMINE AND SPERMIDINE CONTENT OF LACTIC ACID BACTERIA

    PubMed Central

    Guirard, Beverly M.; Snell, Esmond E.

    1964-01-01

    Guirard, Beverly M. (University of California, Berkeley), and Esmond E. Snell. Effect of polyamine structure on growth and spermine and spermidine content of lactic acid bacteria. J. Bacteriol. 88:72–80. 1964.—Growth from small inocula of six species of lactobacilli was stimulated by addition of spermine or spermidine to a defined medium; none of four streptococcal species showed this effect. Lactobacillus casei was stimulated to the greatest extent. Several homologues and analogues partially duplicated the growth-promoting effects of spermidine; one inactive homologue, N-(3-aminopropyl)-1,6-hexanediamine, competitively inhibited the growth response to spermidine and spermine, and reduced or eliminated the response to several weakly active compounds. A procedure for separation of spermine and spermidine, and their estimation by bioassay with L. casei, was developed and applied to the estimation of these compounds in bacterial cells. Both compounds are present in lactic acid bacteria in amounts much smaller (1 to 5%) than those found in Escherichia coli. Addition of spermine or spermidine to the growth medium results in large accumulations in the cells, and the two amines show limited interconvertibility. Putrescine does not increase the cell content of either spermine or spermidine. Presence of the inhibitor prevents accumulation of the growth-stimulating amines. The polyamines appear to fill at least two valuable roles in the cell, one relatively nonspecific in its structural requirements, and one filled only by spermine and spermidine or their nearest homologues. N-(3-aminopropyl)-1,6-hexanediamine appears to prevent the latter function by competition for an appropriate cellular receptor. PMID:14197908

  18. Phylogenetic and Kinetic Diversity of Aerobic Vinyl Chloride-Assimilating Bacteria from Contaminated Sites

    PubMed Central

    Coleman, Nicholas V.; Mattes, Timothy E.; Gossett, James M.; Spain, Jim C.

    2002-01-01

    Aerobic bacteria that grow on vinyl chloride (VC) have been isolated previously, but their diversity and distribution are largely unknown. It is also unclear whether such bacteria contribute to the natural attenuation of VC at chlorinated-ethene-contaminated sites. We detected aerobic VC biodegradation in 23 of 37 microcosms and enrichments inoculated with samples from various sites. Twelve different bacteria (11 Mycobacterium strains and 1 Nocardioides strain) capable of growth on VC as the sole carbon source were isolated, and 5 representative strains were examined further. All the isolates grew on ethene in addition to VC and contained VC-inducible ethene monooxygenase activity. The Mycobacterium strains (JS60, JS61, JS616, and JS617) all had similar growth yields (5.4 to 6.6 g of protein/mol), maximum specific growth rates (0.17 to 0.23 day−1), and maximum specific substrate utilization rates (9 to 16 nmol/min/mg of protein) with VC. The Nocardioides strain (JS614) had a higher growth yield (10.3 g of protein/mol), growth rate (0.71 day−1), and substrate utilization rate (43 nmol/min/mg of protein) with VC but was much more sensitive to VC starvation. Half-velocity constant (Ks) values for VC were between 0.5 and 3.2 μM, while Ks values for oxygen ranged from 0.03 to 0.3 mg/liter. Our results indicate that aerobic VC-degrading microorganisms (predominantly Mycobacterium strains) are widely distributed at sites contaminated with chlorinated solvents and are likely to be responsible for the natural attenuation of VC. PMID:12450841

  19. Antifungal sourdough lactic acid bacteria as biopreservation tool in quinoa and rice bread.

    PubMed

    Axel, Claudia; Brosnan, Brid; Zannini, Emanuele; Furey, Ambrose; Coffey, Aidan; Arendt, Elke K

    2016-12-19

    The use of sourdough fermented with specific strains of antifungal lactic acid bacteria can reduce chemical preservatives in bakery products. The main objective of this study was to investigate the production of antifungal carboxylic acids after sourdough fermentation of quinoa and rice flour using the antifungal strains Lactobacillus reuteri R29 and Lactobacillus brevis R2Δ as bioprotective cultures and the non-antifungal L. brevis L1105 as a negative control strain. The impact of the fermentation substrate was evaluated in terms of metabolic activity, acidification pattern and quantity of antifungal carboxylic acids. These in situ produced compounds (n=20) were extracted from the sourdough using a QuEChERS method and detected by a new UHPLC-MS/MS chromatography. Furthermore, the sourdough was applied in situ using durability tests against environmental moulds to investigate the biopreservative potential to prolong the shelf life of bread. Organic acid production and TTA values were lowest in rice sourdough. The sourdough fermentation of the different flour substrates generated a complex and significantly different profile of carboxylic acids. Extracted quinoa sourdough detected the greatest number of carboxylic acids (n=11) at a much higher concentration than what was detected from rice sourdough (n=9). Comparing the lactic acid bacteria strains, L. reuteri R29 fermented sourdoughs contained generally higher concentrations of acetic and lactic acid but also the carboxylic acids. Among them, 3-phenyllactic acid and 2-hydroxyisocaproic acid were present at a significant concentration. This was correlated with the superior protein content of quinoa flour and its high protease activity. With the addition of L. reuteri R29 inoculated sourdough, the shelf life was extended by 2 days for quinoa (+100%) and rice bread (+67%) when compared to the non-acidified controls. The L. brevis R2Δ fermented sourdough bread reached a shelf life of 4 days for quinoa (+100%) and

  20. Influence of sodium chloride, pH, and lactic acid bacteria on anaerobic lactic acid utilization during fermented cucumber spoilage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cucumbers are preserved commercially by natural fermentations in 5% to 8% sodium chloride (NaCl) brines. Occasionally, fermented cucumbers spoil after the primary fermentation is complete. This spoilage has been characterized by decreases in lactic acid and a rise in brine pH caused by microbial ins...

  1. Evaluation of the 3M™ Petrifilm™ Rapid Aerobic Count Plate for the Enumeration of Aerobic Bacteria: Collaborative Study, First Action 2015.13.

    PubMed

    Bird, Patrick; Flannery, Jonathan; Crowley, Erin; Agin, James; Goins, David; Jechorek, Robert

    2016-05-01

    The 3M™ Petrifilm™ Rapid Aerobic Count (RAC) Plate is a sample-ready culture medium system containing dual-sensor indicator technology for the rapid quantification of aerobic bacteria in food products. The 3M Petrifilm RAC Plate was compared to the U.S. Food and Drug Administration Bacteriological Analytical Manual (FDA BAM) Chapter 3 (Aerobic Plate Count) for the enumeration of aerobic bacteria in raw easy-peel shrimp and the Standard Methods for the Examination of Dairy Products (SMEDP) Chapter 6 (Standard Plate Count Method) for the enumeration of aerobic bacteria in pasteurized skim milk and instant nonfat dry milk (instant NFDM). The 3M Petrifilm RAC Plate was evaluated using a paired study design in a multilaboratory collaborative study following current AOAC validation guidelines. Three target contamination levels (low, 10-100 CFU/g; medium, 100-1000 CFU/g; and high 1000-10 000 CFU/g) were evaluated for naturally occurring aerobic microflora for each matrix. For raw easy-peel shrimp, duplicate 3M Petrifilm RAC Plates were enumerated after 24 ± 2 h incubation at both 32 and 35°C. Pasteurized skim milk 3M Petrifilm RAC Plates were enumerated after 24 ± 2 h incubation at 32°C, and instant NFDM 3M Petrifilm RAC Plates were enumerated after 48 ± 3 h incubation at 32°C. No statistical difference was observed between 3M Petrifilm RAC Plate and FDA BAM or SMEDP reference methods for each contamination level.

  2. Characteristics of alcohol dehydrogenases of certain aerobic bacteria representing human colonic flora.

    PubMed

    Nosova, T; Jousimies-Somer, H; Kaihovaara, P; Jokelainen, K; Heine, R; Salaspuro, M

    1997-05-01

    We have recently proposed the existence of a bacteriocolonic pathway for ethanol oxidation [i.e., ethanol is oxidized by alcohol dehydrogenases (ADHs) of intestinal bacteria resulting in high intracolonic levels of reactive and toxic acetaldehyde]. The aim of this in vitro study was to characterize further ADH activity of some aerobic bacteria, representing the normal human colonic flora. These bacteria were earlier shown to possess high cytosolic ADH activities (Escherichia coli IH 133369, Klebsiella pneumoniae IH 35385, Klebsiella oxytoca IH 35339, Pseudomonas aeruginosa IH 35342, and Hafnia alvei IH 53227). ADHs of the tested bacteria strongly preferred NAD as a cofactor. Marked ADH activities were found in all bacteria, even at low ethanol concentrations (1.5 mM) that may occur in the colon due to bacterial fermentation. The Km for ethanol varied from 29.9 mM for K. pneumoniae to 0.06 mM for Hafnia alvei. The inhibition of ADH by 4-methylpyrazole was found to be of the competitive type in 4 of 5 bacteria, and Ki varied from 18.26 +/- 3.3 mM for Escherichia coli to 0.47 +/- 0.13 mM for K. pneumoniae. At pH 7.4, ADH activity was significantly lower than at pH 9.6 in four bacterial strains. ADH of K. oxytoca, however, showed almost equal activities at neutral pH and at 9.6. In conclusion, NAD-linked alcohol dehydrogenases of aerobic colonic bacteria possess low apparent Km's for ethanol. Accordingly, they may oxidize moderate amounts of ethanol ingested during social drinking with nearly maximal velocity. This may result in the marked production of intracolonic acetaldehyde. Kinetic characteristics of the bacterial enzymes may enable some of them to produce acetaldehyde even from endogenous ethanol formed by other bacteria via alcoholic fermentation. The microbial ADHs were inhibited by 4-methylpyrazole by the same competitive inhibition as hepatic ADH, however, with nearly 1000 times lower susceptibility. Individual variations in human colonic flora may thus

  3. Antigenotoxic activity of lactic acid bacteria, prebiotics, and products of their fermentation against selected mutagens.

    PubMed

    Nowak, Adriana; Śliżewska, Katarzyna; Otlewska, Anna

    2015-12-01

    Dietary components such as lactic acid bacteria (LAB) and prebiotics can modulate the intestinal microbiota and are thought to be involved in the reduction of colorectal cancer risk. The presented study measured, using the comet assay, the antigenotoxic activity of both probiotic and non-probiotic LAB, as well as some prebiotics and the end-products of their fermentation, against fecal water (FW). The production of short chain fatty acids by the bacteria was quantified using HPLC. Seven out of the ten tested viable strains significantly decreased DNA damage induced by FW. The most effective of them were Lactobacillus mucosae 0988 and Bifidobacterium animalis ssp. lactis Bb-12, leading to a 76% and 80% decrease in genotoxicity, respectively. The end-products of fermentation of seven prebiotics by Lactobacillus casei DN 114-001 exhibited the strongest antigenotoxic activity against FW, with fermented inulin reducing genotoxicity by 75%. Among the tested bacteria, this strain produced the highest amounts of butyrate in the process of prebiotic fermentation, and especially from resistant dextrin (4.09 μM/mL). Fermented resistant dextrin improved DNA repair by 78% in cells pre-treated with 6.8 μM methylnitronitrosoguanidine (MNNG). Fermented inulin induced stronger DNA repair in cells pre-treated with mutagens (FW, 25 μM hydrogen peroxide, or MNNG) than non-fermented inulin, and the efficiency of DNA repair after 120 min of incubation decreased by 71%, 50% and 70%, respectively. The different degrees of genotoxicity inhibition observed for the various combinations of bacteria and prebiotics suggest that this effect may be attributable to carbohydrate type, SCFA yield, and the ratio of the end-products of prebiotic fermentation.

  4. Cytofluorometric detection of wine lactic acid bacteria: application of malolactic fermentation to the monitoring.

    PubMed

    Salma, Mohammad; Rousseaux, Sandrine; Sequeira-Le Grand, Anabelle; Alexandre, Hervé

    2013-01-01

    In this study we report for the first time a rapid, efficient and cost-effective method for the enumeration of lactic acid bacteria (LAB) in wine. Indeed, up to now, detection of LAB in wine, especially red wine, was not possible. Wines contain debris that cannot be separated from bacteria using flow cytometry (FCM). Furthermore, the dyes tested in previous reports did not allow an efficient staining of bacteria. Using FCM and a combination of BOX/PI dyes, we were able to count bacteria in wines. The study was performed in wine inoculated with Oenococcus oeni (10(6) CFU ml(-1)) stained with either FDA or BOX/PI and analyzed by FCM during the malolactic fermentation (MLF). The analysis show a strong correlation between the numbers of BOX/PI-stained cells determined by FCM and the cell numbers determined by plate counts (red wine: R (2) ≥ 0.97, white wine R (2) ≥ 0.965). On the other hand, we found that the enumeration of O. oeni labeled with FDA was only possible in white wine (R (2) ≥ 0.97). Viable yeast and LAB populations can be rapidly discriminated and quantified in simultaneous malolactic-alcoholic wine fermentations using BOX/PI and scatter parameters in a one single measurement. This rapid procedure is therefore a suitable method for monitoring O. oeni populations during winemaking, offers a detection limit of <10(4) CFU ml(-1) and can be considered a useful method for investigating the dynamics of microbial growth in wine and applied for microbiological quality control in wineries.

  5. Stochastic modelling of Listeria monocytogenes single cell growth in cottage cheese with mesophilic lactic acid bacteria from aroma producing cultures.

    PubMed

    Østergaard, Nina Bjerre; Christiansen, Lasse Engbo; Dalgaard, Paw

    2015-07-02

    A stochastic model was developed for simultaneous growth of low numbers of Listeria monocytogenes and populations of lactic acid bacteria from the aroma producing cultures applied in cottage cheese. During more than two years, different batches of cottage cheese with aroma culture were analysed for pH, lactic acid concentration and initial concentration of lactic acid bacteria. These data and bootstrap sampling were used to represent product variability in the stochastic model. Lag time data were estimated from observed growth data (lactic acid bacteria) and from literature on L. monocytogenes single cells. These lag time data were expressed as relative lag times and included in growth models. A stochastic model was developed from an existing deterministic growth model including the effect of five environmental factors and inter-bacterial interaction [Østergaard, N.B, Eklöw, A and Dalgaard, P. 2014. Modelling the effect of lactic acid bacteria from starter- and aroma culture on growth of Listeria monocytogenes in cottage cheese. International Journal of Food Microbiology. 188, 15-25]. Growth of L. monocytogenes single cells, using lag time distributions corresponding to three different stress levels, was simulated. The simulated growth was subsequently compared to growth of low concentrations (0.4-1.0 CFU/g) of L. monocytogenes in cottage cheese, exposed to similar stresses, and in general a good agreement was observed. In addition, growth simulations were performed using population relative lag time distributions for L. monocytogenes as reported in literature. Comparably good predictions were obtained as for the simulations performed using lag time data for individual cells of L. monocytogenes. Therefore, when lag time data for individual cells are not available, it was suggested that relative lag time distributions for L. monocytogenes can be used as a qualified default assumption when simulating growth of low concentrations of L. monocytogenes.

  6. Control of Listeria monocytogenes in fresh cheese using protective lactic acid bacteria.

    PubMed

    Coelho, M C; Silva, C C G; Ribeiro, S C; Dapkevicius, M L N E; Rosa, H J D

    2014-11-17

    In the past years, there has been a particular focus on the application of bacteriocins produced by lactic acid bacteria (LAB) in controlling the growth of pathogenic bacteria in foods. The aim of this study was to select LAB strains with antimicrobial activity, previously isolated from a traditional Azorean artisanal cheese (Pico cheese), in order to identify those with the greatest potential in reducing Listeria monocytogenes in fresh cheese. Eight bacteriocin producer strains identified as Lactococcus lactis (1) and Enterococcus faecalis (7) were tested. In general, the bacteriocin-producing strains presented a moderate growth in fresh cheese at refrigeration temperatures (4 °C), increasing one log count in three days. They exhibited slow acidification capacity, despite the increased production of lactic acid displayed by some strains after 24h. Bacteriocin activity was only detected in the whey of fresh cheese inoculated with two Enterococcus strains, but all cheeses made with bacteriocin-producing strains inhibited L. monocytogenes growth in the agar diffusion bioassay. No significant differences were found in overall sensory evaluation made by a non-trained panel of 50-52 tasters using the isolates as adjunct culture in fresh cheese, with the exception of one Enterococcus strain. To test the effect of in situ bacteriocin production against L. monocytogenes, fresh cheese was made from pasteurized cows' milk inoculated with bacteriocin-producing LAB and artificially contaminated with approximately 10(6) CFU/mL of L. monocytogenes. The numbers of L. monocytogenes were monitored during storage of fresh cheese at refrigeration temperature (4 °C) for up to 15 days. All strains controlled the growth of L. monocytogenes, although some Enterococcus were more effective in reducing the pathogen counts. After 7 days, this reduction was of approximately 4 log units compared to the positive control. In comparison, an increase of 4 log CFU/mL in pathogen numbers was

  7. Current state of purification, isolation and analysis of bacteriocins produced by lactic acid bacteria.

    PubMed

    Kaškonienė, Vilma; Stankevičius, Mantas; Bimbiraitė-Survilienė, Kristina; Naujokaitytė, Gintarė; Šernienė, Loreta; Mulkytė, Kristina; Malakauskas, Mindaugas; Maruška, Audrius

    2017-02-01

    The scientific interest for the search of natural means of microbial inhibitors has not faded for several years. A search of natural antibiotics, so-called bacteriocins which are produced by lactic acid bacteria (LAB), gains a huge attention of the scientists in the last century, in order to reduce the usage of synthetic food additives. Pure bacteriocins with wide spectra of antibacterial activity are promising among the natural biopreservatives. The usage of bacteriocin(s) producing LAB as starter culture for the fermentation of some food products, in order to increase their shelf-life, when synthetic preservatives are not allowable, is also possible. There are a lot of studies focusing on the isolation of new bacteriocins from traditional fermented food, dairy products and other foods or sometimes even from unusual non-food matrices. Bacteriocins producing bacteria have been isolated from different sources with the different antibacterial activity against food-borne microorganisms. This review covers the classification of bacteriocins, diversity of sources of bacteriocin(s) producing LAB, antibacterial spectra of isolated bacteriocins and analytical methods for the bacteriocin purification and analysis within the last 15 years.

  8. A natural odor attraction between lactic acid bacteria and the nematode Caenorhabditis elegans.

    PubMed

    Choi, Jae Im; Yoon, Kyoung-Hye; Subbammal Kalichamy, Saraswathi; Yoon, Sung-Sik; Il Lee, Jin

    2016-03-01

    Animal predators can track prey using their keen sense of smell. The bacteriovorous nematode Caenorhabditis elegans employs sensitive olfactory sensory neurons that express vertebrate-like odor receptors to locate bacteria. C. elegans displays odor-related behaviors such as attraction, aversion and adaptation, but the ecological significance of these behaviors is not known. Using a combination of food microbiology and genetics, we elucidate a possible predator-prey relationship between C. elegans and lactic acid bacteria (LAB) in rotting citrus fruit. LAB produces the volatile odor diacetyl as an oxidized by-product of fermentation in the presence of citrate. We show that C. elegans is attracted to LAB when grown on citrate media or Citrus medica L, commonly known as yuzu, a citrus fruit native to East Asia, and this attraction is mediated by the diacetyl odor receptor, ODR-10. We isolated a wild LAB strain and a wild C. elegans-related nematode from rotten yuzu, and demonstrate that the wild nematode was attracted to the diacetyl produced by LAB. These results not only identify an ecological function for a C. elegans olfactory behavior, but contribute to the growing understanding of ecological relationships between the microbial and metazoan worlds.

  9. Diversity of lactic acid bacteria in two Flemish artisan raw milk Gouda-type cheeses.

    PubMed

    Van Hoorde, Koenraad; Verstraete, Tine; Vandamme, Peter; Huys, Geert

    2008-10-01

    PCR-denaturing gradient gel electrophoresis (PCR-DGGE) was used to study the diversity of lactic acid bacteria (LAB) in two Flemish artisan raw milk Gouda-type cheeses. In parallel, conventional culturing was performed. Isolates were identified using (GTG)(5)-PCR and sequence analysis of 16S rRNA and pheS genes. Discriminant analysis revealed some differences in overall LAB diversity between the two batches and between the two cheeses. Within each batch, the diversity of 8- and 12-week-old cheeses was relatively similar. Conventional isolation mainly revealed the presence of Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus rhamnosus and Pediococcus pentosaceus. PCR-DGGE revealed the presence of three species of which no isolates were recovered, i.e. Enterococcus faecalis, Lactobacillus parabuchneri and Lactobacillus gallinarum. Conversely, not all isolated bacteria were detected by PCR-DGGE. We recommend the integrated use of culture-dependent and -independent approaches to maximally encompass the taxonomic spectrum of LAB occurring in Gouda-type and other cheeses.

  10. Selection of enhanced antimicrobial activity posing lactic acid bacteria characterised by (GTG)5-PCR fingerprinting.

    PubMed

    Šalomskienė, Joana; Abraitienė, Asta; Jonkuvienė, Dovilė; Mačionienė, Irena; Repečkienė, Jūratė

    2015-07-01

    The aim of the study was a detail evaluation of genetic diversity among the lactic acid bacteria (LAB) strains having an advantage of a starter culture in order to select genotypically diverse strains with enhanced antimicrobial effect on some harmfull and pathogenic microorganisms. Antimicrobial activity of LAB was performed by the agar well diffusion method and was examined against the reference strains and foodborne isolates of Bacillus cereus, Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Salmonella Typhimurium. Antifungal activity was tested against the foodborne isolates of Candida parapsilosis, Debaromyces hansenii, Kluyveromyces marxianus, Pichia guilliermondii, Yarowia lipolytica, Aspergillus brasiliensis, Aspergillus versicolor, Cladosporium herbarum, Penicillium chrysogenum and Scopulariopsis brevicaulis. A total 40 LAB strains representing Lactobacillus (23 strains), Lactococcus (13 strains) and Streptococcus spp. (4 strains) were characterised by repetitive sequence based polymerase chain reaction fingerprinting which generated highly discriminatory profiles, confirmed the identity and revealed high genotypic heterogeneity among the strains. Many of tested LAB demonstrated strong antimicrobial activity specialised against one or few indicator strains. Twelve LAB strains were superior in suppressing growth of the whole complex of pathogenic bacteria and fungi. These results demonstrated that separate taxonomic units offered different possibilities of selection for novel LAB strains could be used as starter cultures enhancing food preservation.

  11. Influence of wine-like conditions on arginine utilization by lactic acid bacteria.

    PubMed

    Araque, Isabel; Reguant, Cristina; Rozès, Nicolas; Bordons, Albert

    2011-12-01

    Wine can contain trace amounts of ethyl carbamate (EC), a carcinogen formed when ethanol reacts with carbamyl compounds such as citrulline. EC is produced from arginine by lactic acid bacteria (LAB), e.g., Lactobacillus and Pediococcus. Although the amounts of EC in wine are usually negligible, over the last few years there has been a slight but steady increase, as climate change has increased temperatures and alcohol levels have become proportionately higher, both of which favor EC formation. In this study, resting cells of LAB were used to evaluate the effects of ethanol, glucose, malic acid, and low pH on the ability of non-oenococcal strains of these bacteria to degrade arginine and excrete citrulline. Malic acid was found to clearly inhibit arginine consumption in all strains. The relation between citrulline produced and arginine consumed was clearly higher in the presence of ethanol (10-12%) and at low pH (3.0), which is consistent with both the decreased amount of ornithine produced from arginine and the reduction in arginine degradation. In L. brevis and L. buchneri strains isolated from wine and beer, respectively, the synthesis of citrulline from arginine was highest.

  12. Biofilm formation by lactic acid bacteria and resistance to environmental stress.

    PubMed

    Kubota, Hiromi; Senda, Shouko; Nomura, Nobuhiko; Tokuda, Hajime; Uchiyama, Hiroo

    2008-10-01

    We investigated the formation of biofilms by 3 type strains of lactic acid bacteria (LAB), Lactobacillus plantarum, Lactobacillus brevis and Lactobacillus fructivorans, as representatives of LAB that cause food deterioration or contamination. Lactobacillus plantarum subsp. plantarum JCM1149 and Lactobacillus brevis JCM1059 appeared to adhere and accumulate on glass cover slips. Lactobacillus fructivorans JCM1117 cells made thin cellophane-like biofilms, and most of the biofilm cells became longer than the planktonic cells. We tested the resistance of biofilm and planktonic L. plantarum subsp. plantarum JCM1149 cells to acetic acid and ethanol, which strongly inhibit the growth of bacteria and are important in food preservation. The biofilm cells were more resistant than the planktonic cells and the surfaces of the treated planktonic cells were badly damaged, whereas those of the biofilm cells were only slightly damaged. We isolated 43 LAB from onions and the biofolm cells of an isolate, L. plantarum M606 also had high resistance. These results demonstrate the significance of studying biofilms of LAB in the food industry.

  13. Fast identification of wine related lactic acid bacteria by multiplex PCR.

    PubMed

    Petri, A; Pfannebecker, J; Fröhlich, J; König, H

    2013-02-01

    The microflora of must and wine consists of yeasts, acetic acid bacteria and lactic acid bacteria (LAB). The latter group plays an important role for wine quality. The malolactic fermentation carried out by LAB leads to deacidification and stabilisation of wines. Nevertheless, LAB are often associated with wine spoilage. They are mainly responsible for the formation of biogenic amines. Furthermore, some strains produce exopolysaccharide slimes, acetic acid, diacetyl and other off-flavours. In this context a better monitoring of the vinification process is crucial to improve wine quality. Moreover, a lot of biodiversity studies would also profit from a fast and reliable identification method. In this study, we propose a species-specific multiplex PCR system for a rapid and simultaneous detection of 13 LAB species, frequently occurring in must or wine: Lactobacillus brevis, Lb. buchneri, Lb. curvatus, Lb. hilgardii, Lb. plantarum, Leuconostoc mesenteroides, Oenococcus oeni, Pediococcus acidilactici, P. damnosus, P. inopinatus, P. parvulus, P. pentosaceus and Weissella paramesenteroides.

  14. Evaluation of culture media for selective enumeration of bifidobacteria and lactic acid bacteria.

    PubMed

    Süle, Judit; Kõrösi, Tímea; Hucker, Attila; Varga, László

    2014-01-01

    The purpose of this study was to test the suitability of Transgalactosylated oligosaccharides-mupirocin lithium salt (TOS-MUP) and MRS-clindamycin-ciprofloxacin (MRS-CC) agars, along with several other culture media, for selectively enumerating bifidobacteria and lactic acid bacteria (LAB) species commonly used to make fermented milks. Pure culture suspensions of a total of 13 dairy bacteria strains, belonging to eight species and five genera, were tested for growth capability under various incubation conditions. TOS-MUP agar was successfully used for the selective enumeration of both Bifidobacterium animalis subsp. lactis BB-12 and B. breve M-16 V. MRS-CC agar showed relatively good selectivity for Lactobacillus acidophilus, however, it also promoted the growth of Lb. casei strains. For this reason, MRS-CC agar can only be used as a selective medium for the enumeration of Lb. acidophilus if Lb. casei is not present in a product at levels similar to or exceeding those of Lb. acidophilus. Unlike bifidobacteria and coccus-shaped LAB, all the lactobacilli strains involved in this work were found to grow well in MRS pH 5.4 agar incubated under anaerobiosis at 37 °C for 72 h. Therefore, this method proved to be particularly suitable for the selective enumeration of Lactobacillus spp.

  15. Linking wine lactic acid bacteria diversity with wine aroma and flavour.

    PubMed

    Cappello, Maria Stella; Zapparoli, Giacomo; Logrieco, Antonio; Bartowsky, Eveline J

    2017-02-21

    In the last two decades knowledge on lactic acid bacteria (LAB) associated with wine has increased considerably. Investigations on genetic and biochemistry of species involved in malolactic fermentation, such as Oenococcus oeni and of Lactobacillus have enabled a better understand of their role in aroma modification and microbial stability of wine. In particular, the use of molecular techniques has provided evidence on the high diversity at species and strain level, thus improving the knowledge on wine LAB taxonomy and ecology. These tools demonstrated to also be useful to detect strains with potential desirable or undesirable traits for winemaking purposes. At the same time, advances on the enzymatic properties of wine LAB responsible for the development of wine aroma molecules have been undertaken. Interestingly, it has highlighted the high intraspecific variability of enzymatic activities such as glucosidase, esterase, proteases and those related to citrate metabolism within the wine LAB species. This genetic and biochemistry diversity that characterizes wine LAB populations can generate a wide spectrum of wine sensory outcomes. This review examines some of these interesting aspects as a way to elucidate the link between LAB diversity with wine aroma and flavour. In particular, the correlation between inter- and intra-species diversity and bacterial metabolic traits that affect the organoleptic properties of wines is highlighted with emphasis on the importance of enzymatic potential of bacteria for the selection of starter cultures to control MLF and to enhance wine aroma.

  16. Bacteriocinogenic lactic acid bacteria for the biopreservation of meat and meat products.

    PubMed

    Hugas, M

    1998-01-01

    The consumer demands for less preserved foods and the development of new food systems to fulfil these demands, urges new hurdles for pathogen growth. The strategies for pathogen reduction are not selective for pathogenic microorganism and therefore the non-spoilage microorganisms may become also inactivated, from this situation a question of concern about a freer way for pathogen growth is arised. Biopreservation refers to the extended storage life and enhanced safety of foods using their natural or controlled microflora and (or) their antibacterial products. In meats, lactic acid bacteria (LAB) constitute a part of the initial microflora which develops easily after meat is processed. LAB growth in meat can cause microbial interference to spoilage and pathogenic bacteria through several mechanisms, specially bacteriocins. The paper deals with the description of meat-borne bacteriocins and their application in meat and meat products either to extend the shelf life or to inhibit meat pathogens. The application of bacteriocinogenic LAB together with new technological hurdles is discussed.

  17. Lactic acid bacteria--20 years exploring their potential as live vectors for mucosal vaccination.

    PubMed

    Wyszyńska, Agnieszka; Kobierecka, Patrycja; Bardowski, Jacek; Jagusztyn-Krynicka, Elżbieta Katarzyna

    2015-04-01

    Lactic acid bacteria (LAB) are a diverse group of Gram-positive, nonsporulating, low G + C content bacteria. Many of them have been given generally regarded as safe status. Over the past two decades, intensive genetic and molecular research carried out on LAB, mainly Lactococcus lactis and some species of the Lactobacillus genus, has revealed new, potential biomedical LAB applications, including the use of LAB as adjuvants, immunostimulators, or therapeutic drug delivery systems, or as factories to produce therapeutic molecules. LAB enable immunization via the mucosal route, which increases effectiveness against pathogens that use the mucosa as the major route of entry into the human body. In this review, we concentrate on the encouraging application of Lactococcus and Lactobacillus genera for the development of live mucosal vaccines. First, we present the progress that has recently been made in the field of developing tools for LAB genetic manipulations, which has resulted in the successful expression of many bacterial, parasitic, and viral antigens in LAB strains. Next, we discuss the factors influencing the efficacy of the constructed vaccine prototypes that have been tested in various animal models. Apart from the research focused on an application of live LABs as carriers of foreign antigens, a lot of work has been recently done on the potential usage of nonliving, nonrecombinant L. lactis designated as Gram-positive enhancer matrix (GEM), as a delivery system for mucosal vaccination. The advantages and disadvantages of both strategies are also presented.

  18. A natural odor attraction between lactic acid bacteria and the nematode Caenorhabditis elegans

    PubMed Central

    Choi, Jae Im; Yoon, Kyoung-hye; Subbammal Kalichamy, Saraswathi; Yoon, Sung-Sik; Il Lee, Jin

    2016-01-01

    Animal predators can track prey using their keen sense of smell. The bacteriovorous nematode Caenorhabditis elegans employs sensitive olfactory sensory neurons that express vertebrate-like odor receptors to locate bacteria. C. elegans displays odor-related behaviors such as attraction, aversion and adaptation, but the ecological significance of these behaviors is not known. Using a combination of food microbiology and genetics, we elucidate a possible predator–prey relationship between C. elegans and lactic acid bacteria (LAB) in rotting citrus fruit. LAB produces the volatile odor diacetyl as an oxidized by-product of fermentation in the presence of citrate. We show that C. elegans is attracted to LAB when grown on citrate media or Citrus medica L, commonly known as yuzu, a citrus fruit native to East Asia, and this attraction is mediated by the diacetyl odor receptor, ODR-10. We isolated a wild LAB strain and a wild C. elegans-related nematode from rotten yuzu, and demonstrate that the wild nematode was attracted to the diacetyl produced by LAB. These results not only identify an ecological function for a C. elegans olfactory behavior, but contribute to the growing understanding of ecological relationships between the microbial and metazoan worlds. PMID:26241504

  19. Influence of the dairy environment on gene expression and substrate utilization in lactic acid bacteria.

    PubMed

    Klaenhammer, Todd R; Azcarate-Peril, M Andrea; Altermann, Eric; Barrangou, Rodolphe

    2007-03-01

    Lactic acid bacteria (LAB) are widely used for the industrial production of fermented dairy products and form a group of related low-GC-content gram-positive bacteria. The major species used in dairy manufacturing are Lactobacillus, Lactococcus, Streptococcus, and Leuconostoc. Traditionally most are applied as starter cultures for dairy fermentations or used as probiotic cultures, delivered in dairy vehicles. The appearance of the genomes of Lactococcus lactis, Bidifobacterium longum, Lactobacillus plantarum, L. johnsonii, L. acidophilus, 2 strains of Streptococcus thermophilus, and pending completion of many draft genomic sequences, is now promoting in-depth investigation into the comparative genetic content of LAB. Moreover, whole-genome transcriptional arrays are quickly revealing critical genes/operons that are coordinately expressed and the impact of environmental factors on expression of multiple gene sets. Comparative genomics between multiple genomes is providing insights into genes that are important in metabolic, physiological, and functional roles for different LAB in the environments they inhabit, ranging from the gastrointestinal tract to milk and acidified dairy products.

  20. Antimicrobial Peptides Targeting Gram-negative Pathogens, Produced and Delivered by Lactic Acid Bacteria

    PubMed Central

    Volzing, Katherine; Borrero, Juan; Sadowsky, Michael J.; Kaznessis, Yiannis N.

    2014-01-01

    We present results of tests with recombinant Lactococcus lactis that produce and secrete heterologous antimicrobial peptides with activity against Gram-negative pathogenic Escherichia coli and Salmonella. In an initial screening, the activities of numerous candidate antimicrobial peptides, made by solid state synthesis, were assessed against several indicator pathogenic E. coli and Salmonella strains. Peptides A3APO and Alyteserin were selected as top performers based on high antimicrobial activity against the pathogens tested and on significantly lower antimicrobial activity against L. lactis. Expression cassettes containing the signal peptide of the protein Usp45 fused to the codon optimized sequence of mature A3APO and Alyteserin were cloned under the control of a nisin-inducible promoter nisA and transformed into L. lactis IL1403. The resulting recombinant strains were induced to express and secrete both peptides. A3APO- and Alyteserin-containing supernatants from these recombinant L. lactis inhibited the growth of pathogenic E. coli and Salmonella by up to 20-fold, while maintaining the host’s viability. This system may serve as a model for the production and delivery of antimicrobial peptides by lactic acid bacteria to target Gram-negative pathogenic bacteria populations. PMID:23808914

  1. GH1-family 6-P-β-glucosidases from human microbiome lactic acid bacteria

    PubMed Central

    Michalska, Karolina; Tan, Kemin; Li, Hui; Hatzos-Skintges, Catherine; Bearden, Jessica; Babnigg, Gyorgy; Joachimiak, Andrzej

    2013-01-01

    In lactic acid bacteria and other bacteria, carbohydrate uptake is mostly governed by phosphoenolpyruvate-dependent phosphotransferase systems (PTSs). PTS-dependent translocation through the cell membrane is coupled with phosphorylation of the incoming sugar. After translocation through the bacterial membrane, the β-glycosidic bond in 6′-­P-­β-glucoside is cleaved, releasing 6-P-β-glucose and the respective aglycon. This reaction is catalyzed by 6-P-β-glucosidases, which belong to two glycoside hydrolase (GH) families: GH1 and GH4. Here, the high-resolution crystal structures of GH1 6-P-β-glucosidases from Lactobacillus plantarum (LpPbg1) and Streptococcus mutans (SmBgl) and their complexes with ligands are reported. Both enzymes show hydrolytic activity towards 6′-P-β-glucosides. The LpPbg1 structure has been determined in an apo form as well as in a complex with phosphate and a glucose molecule corresponding to the aglycon molecule. The S. mutans homolog contains a sulfate ion in the phosphate-dedicated subcavity. SmBgl was also crystallized in the presence of the reaction product 6-P-β-glucose. For a mutated variant of the S. mutans enzyme (E375Q), the structure of a 6′-P-salicin complex has also been determined. The presence of natural ligands enabled the definition of the structural elements that are responsible for substrate recognition during catalysis. PMID:23519420

  2. Probiotic lactic acid bacteria and their potential in the prevention and treatment of allergic diseases

    PubMed Central

    Wróblewska, Paula; Adamczuk, Piotr; Silny, Wojciech

    2014-01-01

    Allergy is one of the most important and very common health problems worldwide. To reduce the proportion of people suffering from allergy, alternative methods of prevention and treatment are sought. The aim of this paper is to present the possibilities of probiotics in the prevention and treatment of allergic diseases. Probiotics are live microorganisms belonging mainly to the lactic acid bacteria. They modify the microflora of the human digestive system, especially the intestinal microflora. Prophylactic administration of probiotics in the early stages of life (naturally in breast milk or milk substitute synthetic compounds) is very important because intestinal microflora plays a huge role in the development of the immune system. Prevention of allergies as early as in the prenatal and postnatal periods provides huge opportunities for inhibiting the growing problem of allergy in emerging and highly developed societies. Effects of probiotic therapy depend on many factors such as the species of the microorganism used, the dose size and characteristics of the bacteria such as viability and capacity of adhesion to the intestinal walls. Authors of several studies showed beneficial effects of probiotics in the perinatal period, infancy, and also in adults in the prevention of atopic dermatitis or allergic rhinitis. Probiotics, due to their immunomodulatory properties and safety of use are a good, natural alternative for the prevention and treatment of many diseases including allergies. It is therefore important to explore the knowledge about their use and to carry out further clinical trials. PMID:26155109

  3. Sugar-coated: exopolysaccharide producing lactic acid bacteria for food and human health applications.

    PubMed

    Ryan, P M; Ross, R P; Fitzgerald, G F; Caplice, N M; Stanton, C

    2015-03-01

    The human enteric microbiome represents a veritable organ relied upon by the host for a range of metabolic and homeostatic functions. Through the production of metabolites such as short chain fatty acids (SCFA), folate, vitamins B and K, lactic acid, bacteriocins, peroxides and exopolysaccharides, the bacteria of the gut microbiome provide nutritional components for colonocytes, liver and muscle cells, competitively exclude potential pathogenic organisms and modulate the hosts immune system. Due to the extensive variation in structure, size and composition, microbial exopolysaccharides represent a useful set of versatile natural ingredients for the food industrial sector, both in terms of their rheological properties and in many cases, their associated health benefits. The exopolysaccharide-producing bacteria that fall within the 35 Lactobacillus and five Bifidobacterium species which have achieved qualified presumption of safety (QPS) and generally recognised as safe (GRAS) status are of particular interest, as their inclusion in food products can avoid considerable scrutiny. In addition, additives commonly utilised by the food industry are becoming unattractive to the consumer, due to the demand for a more 'natural' and 'clean labelled' diet. In situ production of exopolysaccharides by food-grade cultures in many cases confers similar rheological and sensory properties in fermented dairy products, as traditional additives, such as hydrocolloids, collagen and alginate. This review will focus on microbial synthesis of exopolysaccharides, the human health benefits of dietary exopolysaccharides and the technofunctional applications of exopolysaccharide-synthesising microbes in the food industry.

  4. Effect of mannoproteins on the growth, gastrointestinal viability, and adherence to Caco-2 cells of lactic acid bacteria.

    PubMed

    Ganan, M; Carrascosa, A V; de Pascual-Teresa, S; Martinez-Rodriguez, A J

    2012-03-01

    Yeast cell wall (YCW) preparations and yeast mannoprotein extracts have been effective against some enteropathogenic bacteria as Campylobacter jejuni, Escherichia coli, and Salmonella, and they can affect the population of beneficial lactic acid bacteria (LAB). In this work, we studied the effect of a mannoprotein extract on five strains of LAB. This extract was metabolised by the bacteria, enhancing their survival in simulated gastrointestinal juice, and increasing the adherence of Lactobacillus plantarum, L. salivarius, and Enterococcus faecium to Caco-2 cells. Yeast mannoproteins are promising naturally occurring compounds that could be used to enhance LAB intestinal populations and control pathogens.

  5. The combined efficacy of carvacrol and modified atmosphere packaging on the survival of Salmonella, Campylobacter jejuni and lactic acid bacteria on turkey breast cutlets.

    PubMed

    Nair, Divek V T; Kiess, Aaron; Nannapaneni, Rama; Schilling, Wes; Sharma, Chander Shekhar

    2015-08-01

    The primary objective of this study was to determine the efficacy of carvacrol in combination with modified atmosphere packaging (MAP) in reducing Salmonella on turkey breast cutlets stored at 4 °C. In experiment I, carvacrol (0.5, 1, and 2% v/v) was applied as surface treatment and samples were stored under aerobic condition or as surface and dip treatments followed by storage in an environment of 100% carbon dioxide. The findings of the experiment I revealed the synergistic activity of carvacrol with carbon dioxide in reducing Salmonella when used as dip treatment compared to the surface treatment. In experiment II, turkey breast cutlets were dip treated with carvacrol (0.25, 0.5, and 1% v/v) for 30 s and stored under MAP (95% carbon dioxide and 5% oxygen) to evaluate the efficacy against Salmonella, Campylobacter jejuni and lactic acid bacteria on turkey breast cutlets. In experiment II, the combined application of carvacrol and MAP resulted in 1.0-2.0 log CFU/g reduction (P ≤ 0.05) of both Salmonella and Campylobacter on turkey breast cutlets for 7 d storage at 4 °C. MAP alone and in combination with carvacrol reduced lactic acid bacteria (P ≤ 0.05) on cutlets stored at 4 °C for 21 d period. There was no difference (P ≤ 0.05) in meat color among treatments and controls except for an increased paleness of meat (P ≤ 0.05) observed for the 1% carvacrol treated cutlets stored under MAP after 21 d of storage. The high concentration of carbon dioxide and carvacrol treatments did not cause any alteration in meat pH (P ≤ 0.05). In conclusion, carvacrol was effective at a low concentration of 0.25% (v/v) in reducing Salmonella and C. jejuni by ∼1.0 log CFU/g when stored under MAP.

  6. The methanogenic redox cofactor F420 is widely synthesized by aerobic soil bacteria.

    PubMed

    Ney, Blair; Ahmed, F Hafna; Carere, Carlo R; Biswas, Ambarish; Warden, Andrew C; Morales, Sergio E; Pandey, Gunjan; Watt, Stephen J; Oakeshott, John G; Taylor, Matthew C; Stott, Matthew B; Jackson, Colin J; Greening, Chris

    2017-01-01

    F420 is a low-potential redox cofactor that mediates the transformations of a wide range of complex organic compounds. Considered one of the rarest cofactors in biology, F420 is best known for its role in methanogenesis and has only been chemically identified in two phyla to date, the Euryarchaeota and Actinobacteria. In this work, we show that this cofactor is more widely distributed than previously reported. We detected the genes encoding all five known F420 biosynthesis enzymes (cofC, cofD, cofE, cofG and cofH) in at least 653 bacterial and 173 archaeal species, including members of the dominant soil phyla Proteobacteria, Chloroflexi and Firmicutes. Metagenome datamining validated that these genes were disproportionately abundant in aerated soils compared with other ecosystems. We confirmed through high-performance liquid chromatography analysis that aerobically grown stationary-phase cultures of three bacterial species, Paracoccus denitrificans, Oligotropha carboxidovorans and Thermomicrobium roseum, synthesized F420, with oligoglutamate sidechains of different lengths. To understand the evolution of F420 biosynthesis, we also analyzed the distribution, phylogeny and genetic organization of the cof genes. Our data suggest that although the Fo precursor to F420 originated in methanogens, F420 itself was first synthesized in an ancestral actinobacterium. F420 biosynthesis genes were then disseminated horizontally to archaea and other bacteria. Together, our findings suggest that the cofactor is more significant in aerobic bacterial metabolism and soil ecosystem composition than previously thought. The cofactor may confer several competitive advantages for aerobic soil bacteria by mediating their central metabolic processes and broadening the range of organic compounds they can synthesize, detoxify and mineralize.

  7. Growth-inhibition of hiochi bacteria in namazake (raw sake) by bacteriocins from lactic acid bacteria.

    PubMed

    Taniguchi, Masayuki; Ishiyama, Yohei; Takata, Takeomi; Nakanishi, Toshihiro; Kaneoke, Mitsuoki; Watanabe, Ken-ichi; Yanagida, Fujitoshi; Chen, Yi-sheng; Kouya, Tomoaki; Tanaka, Takaaki

    2010-06-01

    The bacteriocins produced by Lactococcus lactis subsp. lactis C101910 (C101910) and NBRC 12007 (NBRC 12007) were used to prevent the growth of sake spoiling hiochi bacteria (Lactobacillus hilgardii, Lactobacillus fructivorans, and Lactobacillus paracasei) in namazake, which is raw (unpasteurized) sake. The bacteriocin concentrations required for decreasing the viable cell concentrations of L. hilgardii and L. fructivorans below the detection limit (1.0 x 10(2) cells/ml) in 24 h from the initial concentration of 4.0-9.5 x 10(5) cells/ml in the namazake at pH 4.5 and at 4 degrees C, were 18-35 U/ml and 5.6 U/ml for the bacteriocin from C101910 and NBRC 12007, respectively. To decrease the viable cell concentration of L. paracasei from the initial concentration of 7.5 x 10(5) cells/ml to below the detection limit (1.0 x 10(2) cells/ml) in 24 h, 350 U/ml bacteriocin from C101910 and 140 U/ml bacteriocin from NBRC 12007 were required. In experiments using McIlvaine buffer (pH 4.5) with 15% ethanol instead of namazake as the medium, the viable cell concentrations of L. hilgardii and L. paracasei decreased to less than 1.0 x 10(2) cells/ml, whereas those of L. fructivorans decreased to less than 1.0 x 10(3) cells/ml, when bacteriocins were added at the concentrations that had proven effective in namazake. The membrane depolarization assay using a fluorescent probe showed that the presence of ethanol stimulated the collapse of the membrane potential induced by bacteriocins. The ethanol induced collapse of the membrane potential suggests that the application of bacteriocins at the storage stage of namazake is more beneficial than when used in other stages of the sake brewing process.

  8. Homofermentative lactic acid bacteria of a traditional cheese, Comlek peyniri from Cappadocia region.

    PubMed

    Bulut, Cisem; Gunes, Hatice; Okuklu, Burcu; Harsa, Sebnem; Kilic, Sevda; Coban, Hatice Sevgi; Yenidunya, Ali Fazil

    2005-02-01

    Comlek peyniri is a typical artisanal cheese in Central Anatolia. This type of cheese was made by using the indigenous lactic acid bacteria (LAB) flora of cow or ewes' milk. Majority of the samples were taken from fresh cheese because the aim was to isolate homofermentative LAB. Initially 661 microbial isolates were obtained from 17 cheese samples. Only 107 were found to be homofermentative LAB. These isolates were selected and identified by using both phenotypic and molecular methods. Phenotypic identification included curd formation from skim milk, catalase test, Gram staining and light microscopy, growth at different temperatures and salt concentrations, arginine hydrolysis, gas production from glucose, and carbohydrate fermentation. Molecular identification was based on the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the 16S rRNA gene-ITS (internally transcribed spacer) region. By combining the phenotypic and molecular identification results, isolates belonging to each of the following genera were determined at species or subspecies level: 54 Lactococcus lactis subsp. lactis, 21 Enterococcus faecium, 3 Ec. faecalis, 2 Ec. durans, 10 Ec. sp., 15 Lactobacillus paracasei subsp. paracasei, and 2 Lb. casei strains. Technological characterisation was also performed by culturing each of the strains in UHT skim milk, and by monitoring pH change and lactic acid production at certain time intervals through the 24 h incubation. Results of the technological characterisation indicated that 33% of the isolates (35 strains) were capable of lowering the pH of UHT milk below 5.3 after 6 h incubation at 30 degrees C. Thirty four of these strains were Lc. lactis subsp. lactis, and only one was an Ec. faecium strain.

  9. Natural Lactic Acid Bacteria Population and Silage Fermentation of Whole-crop Wheat

    PubMed Central

    Ni, Kuikui; Wang, Yanping; Cai, Yimin; Pang, Huili

    2015-01-01

    Winter wheat is a suitable crop to be ensiled for animal feed and China has the largest planting area of this crop in the world. During the ensiling process, lactic acid bacteria (LAB) play the most important role in the fermentation. We investigated the natural population of LAB in whole-crop wheat (WCW) and examined the quality of whole-crop wheat silage (WCWS) with and without LAB inoculants. Two Lactobacillus plantarum subsp. plantarum strains, Zhengzhou University 1 (ZZU 1) selected from corn and forage and grass 1 (FG 1) from a commercial inoculant, were used as additives. The silages inoculated with LAB strains (ZZU 1 and FG 1) were better preserved than the control, with lower pH values (3.5 and 3.6, respectively) (p<0.05) and higher contents of lactic acid (37.5 and 34.0 g/kg of fresh matter (FM), respectively) (p<0.05) than the control. Sixty LAB strains were isolated from fresh material and WCWS without any LAB inoculation. These LAB strains were divided into the following four genera and six species based on their phenotypic, biochemical and phylogenetic characteristics: Leuconostoc pseudomesenteroides, Leuconostoc citreum, Weissella cibaria, Lactococcus lactis subsp. lactis, Lactobacillus buchneri, and Lactobacillus plantarum subsp. plantarum. However, the prevalent LAB, which was predominantly heterofermentative (66.7%), consisted of Leuconostoc pseudomesenteroides, Leuconostoc citreum, Weissella cibaria, and Lactobacillus buchneri. This study revealed that most of isolated LAB strains from control WCWS were heterofermentative and could not grow well at low pH condition; the selective inoculants of Lactobacillus strains, especially ZZU 1, could improve WCWS quality significantly. PMID:26104520

  10. Whey fermentation by thermophilic lactic acid bacteria: evolution of carbohydrates and protein content.

    PubMed

    Pescuma, Micaela; Hébert, Elvira María; Mozzi, Fernanda; Font de Valdez, Graciela

    2008-05-01

    Whey, a by-product of the cheese industry usually disposed as waste, is a source of biological and functional valuable proteins. The aim of this work was to evaluate the potentiality of three lactic acid bacteria strains to design a starter culture for developing functional whey-based drinks. Fermentations were performed at 37 and 42 degrees C for 24h in reconstituted whey powder (RW). Carbohydrates, organic acids and amino acids concentrations during fermentation were evaluated by RP-HPLC. Proteolytic activity was measured by the o-phthaldialdehyde test and hydrolysis of whey proteins was analyzed by Tricine SDS-PAGE. The studied strains grew well (2-3log cfu/ml) independently of the temperature used. Streptococcus thermophilus CRL 804 consumed 12% of the initial lactose concentration and produced the highest amount of lactic acid (45 mmol/l) at 24h. Lactobacillus delbrueckii subsp. bulgaricus CRL 454 was the most proteolytic (91 microg Leu/ml) strain and released the branched chain amino acids Leu and Val. In contrast, Lactobacillus acidophilus CRL 636 and S. thermophilus CRL 804 consumed most of the amino acids present in whey. The studied strains were able to degrade the major whey proteins, alpha-lactalbumin being degraded in a greater extent (2.2-3.4-fold) than beta-lactoglobulin. Two starter cultures were evaluated for their metabolic and proteolytic activities in RW. Both cultures acidified and reduced the lactose content in whey in a greater extent than the strains alone. The amino acid release was higher (86 microg/ml) for the starter SLb (strains CRL 804+CRL 454) than for SLa (strains CRL 804+CRL 636, 37 microg/ml). Regarding alpha-lactalbumin and beta-lactoglobulin degradation, no differences were observed as compared to the values obtained with the single cultures. The starter culture SLb showed high potential to be used for developing fermented whey-based beverages.

  11. Antibiotic resistance of lactic acid bacteria isolated from dry-fermented sausages.

    PubMed

    Fraqueza, Maria João

    2015-11-06

    Dry-fermented sausages are meat products highly valued by many consumers. Manufacturing process involves fermentation driven by natural microbiota or intentionally added starter cultures and further drying. The most relevant fermentative microbiota is lactic acid bacteria (LAB) such as Lactobacillus, Pediococcus and Enterococcus, producing mainly lactate and contributing to product preservation. The great diversity of LAB in dry-fermented sausages is linked to manufacturing practices. Indigenous starters development is considered to be a very promising field, because it allows for high sanitary and sensorial quality of sausage production. LAB have a long history of safe use in fermented food, however, since they are present in human gastrointestinal tract, and are also intentionally added to the diet, concerns have been raised about the antimicrobial resistance in these beneficial bacteria. In fact, the food chain has been recognized as one of the key routes of antimicrobial resistance transmission from animal to human bacterial populations. The World Health Organization 2014 report on global surveillance of antimicrobial resistance reveals that this issue is no longer a future prediction, since evidences establish a link between the antimicrobial drugs use in food-producing animals and the emergence of resistance among common pathogens. This poses a risk to the treatment of nosocomial and community-acquired infections. This review describes the possible sources and transmission routes of antibiotic resistant LAB of dry-fermented sausages, presenting LAB antibiotic resistance profile and related genetic determinants. Whenever LAB are used as starters in dry-fermented sausages processing, safety concerns regarding antimicrobial resistance should be addressed since antibiotic resistant genes could be mobilized and transferred to other bacteria.

  12. Molecular characterization of lactic acid bacteria and in situ amylase expression during traditional fermentation of cereal foods.

    PubMed

    Oguntoyinbo, Folarin Anthony; Narbad, Arjan

    2012-09-01

    Lactic acid bacteria play an important role in traditional fermented foods consumed in different countries. Study of their taxonomic structure and diversity is necessary for starter culture selection, improved safety and nutritional enhancement. To achieve these objectives, microbial genomic typing methods were used to study genetic differences of autochthonous bacteria and their distribution in two traditional African fermented cereal foods. A total of 85 predominant bacterial species were isolated from ogi and kunu-zaki obtained from Northern and Southern geographical region of Nigeria. They were identified using combination of 16S rRNA gene sequencing, multilocus sequence analysis (MLSA) based on rpoA, pheS and atpA genes as well as M13-PCR gel fingerprints. The results showed that Lactobacillus fermentum was the most frequently isolated species in ogi (71.4%) and kunu-zaki (84.5%). Other species of lactic acid bacteria (LAB) identified were Lactobacillus plantarum, Streptococcus gallolyticus subsp. macedonicus and Pediococcus pentosaceus. Non lactic acid bacteria isolated from these foods were species belonging to the Bacillus and Staphylococcus. Non-metric multidimensional scaling (nMDS) analysis of the M13-PCR fingerprints for LAB strains showed clonal diversity among strains of the same species. In vitro and in situ expression of amylase gene during fermentation by amylolytic L. plantarum ULAG11 was detected, indicating the potential usefulness of such species for development of starter cultures and for controlled fermentation processes.

  13. Phenotypic and genotypic characterization of lactic acid bacteria from traditional cheese in Khorramabad city of Iran with probiotic potential.

    PubMed

    Ghahremani, Enayat; Mardani, Mahnaz; Rezapour, Sadegh

    2015-03-01

    Lactic acid bacteria (LAB) with proteolitic activity are used as aromatic and antibacterial substances, cholesterol reduces, bile salt hydrolyses, and probiotic. The aims of this project were to isolate and identify natural LAB flora involved in traditional fermentation in cheeses of Khoramabad city and also to survey their probiotic potential. In order to achieve this goal, LAB were isolated and characterized using phenotypic and genotypic methods (PCR-sequencing); in the next stage, they were analyzed lowering cholesterol medium, hydrolysis of the bile, resistance to bile-resistant PH acidic stomach. At the end of the study, 88 cocci and 3 bacill were found: 58 Enterococcus faecium, 16 Enterococcus hirae, 5 Lactococcus lactis, 3 Lactobacillus plantarum, and 9 undetermined. The probiotic results of the bacteria had effects on the reduction of cholesterol, resistance to stomach acid, had relative antibacterial effects, and some strains had effects on hydrolyzing the bile. For further identification, the PCR method and the application of 16s-DNA-ITS genes and its sequencing were found useful. This study showed that lactic acid bacteria in the traditional cheese of the Khorramabad city have relative probiotic effect and that these lactic acid bacteria in fermented milk are suitable.

  14. Use of UV light for the inactivation of Listeria monocytogenes and lactic acid bacteria species in recirculated chill brines.

    PubMed

    Gailunas, K M; Matak, K E; Boyer, R R; Alvarado, C Z; Williams, R C; Sumner, S S

    2008-03-01

    Ready-to-eat meat products have been implicated in several foodborne listeriosis outbreaks. Microbial contamination of these products can occur after thermal processing when products are chilled in salt brines. The objective of this study was to evaluate UV radiation on the inactivation of Listeria monocytogenes and lactic acid bacteria in a model brine chiller system. Two concentrations of brine (7.9% [wt/wt] or 13.2% [wt/wt]) were inoculated with a approximately 6.0 log CFU/ml cocktail of L. monocytogenes or lactic acid bacteria and passed through a UV treatment system for 60 min. Three replications of each bacteria-and-brine combination were performed and resulted in at least a 4.5-log reduction in microbial numbers in all treated brines after exposure to UV light. Bacterial populations were significantly reduced after 5 min of exposure to UV light in the model brine chiller compared with the control, which received no UV light exposure (P < 0.05). The maximum rate of inactivation for both microorganisms in treated brines occurred between minutes 1 and 15 of UV exposure. Results indicate that in-line treatment of chill brines with UV light reduces the number of L. monocytogenes and lactic acid bacteria.

  15. Microbiological and biochemical profile of cv. Conservolea naturally black olives during controlled fermentation with selected strains of lactic acid bacteria.

    PubMed

    Panagou, Efstathios Z; Schillinger, Ulrich; Franz, Charles M A P; Nychas, George-John E

    2008-04-01

    The effect of controlled fermentation processes on the microbial association and biochemical profile of cv. Conservolea naturally black olives processed by the traditional anaerobic method was studied. The different treatments included (a) inoculation with a commercial starter culture of Lactobacillus pentosus, (b) inoculation with a strain of Lactobacillus plantarum isolated from a fermented cassava product and (c) uninoculated spontaneous process. Microbial growth, pH, titratable acidity, organic acids and volatile compounds were monitored throughout the fermentation. The initial microbiota consisted of Gram-negative bacteria, lactic acid bacteria and yeasts. Inhibition of Gram-negative bacteria was evident in all processes. Both starter cultures were effective in establishing an accelerated fermentation process and reduced the survival period of Gram-negative bacteria by 5 days compared with the spontaneous process, minimizing thus the likelihood of spoilage. Higher acidification of the brines was observed in inoculated processes without any significant difference between the two selected starter cultures (113.5 and 117.6mM for L. plantarum and L. pentosus, respectively). L. pentosus was also determined as the major species present during the whole process of spontaneous olive fermentation. It is characteristic that lactic acid fermentation was also initiated rapidly in the spontaneous process, as the conditions of fermentation, mainly the low salt level (6%, w/v) favored the dominance of lactic acid bacteria over yeasts. Lactic, acetic and propionic were the organic acids detected by HPLC in considerable amounts, whereas citric and malic acids were also present at low levels and degraded completely during the processes. Ethanol, methanol, acetaldehyde, ethyl acetate were the major volatile compounds identified by GC. Their concentrations varied among the different treatments, reflecting varying degrees of microbial activity in the brines. The results obtained

  16. Viability of lactic acid bacteria and bifidobacteria in fermented soymilk after drying, subsequent rehydration and storage.

    PubMed

    Wang, Yi-Chieh; Yu, Roch-Chui; Chou, Cheng-Chun

    2004-06-01

    To develop a probiotic dietary adjunct, soymilk fermented with various combinations of lactic acid bacteria (Streptococcus thermophilus and Lactobacillus acidophilus) and bifidobacteria (Bifidobacterium longum and Bifidobacterium infantis) was subjected to freeze-drying and spray-drying. Survival of the starter organisms during the drying process, subsequent rehydration at different temperatures and during a 4-month period of storage under different storage conditions was examined. After freeze-drying, lactic acid bacteria and bifidobacteria exhibited a survival percent of 46.2-75.1% and 43.2-51.9%, respectively, higher than that noted after spray-drying. Regardless of the drying condition, S. thermophilus showed a higher percentage of survival than L. acidophilus, while B. longum survived better than B. infantis. Further study with soymilk fermented with S. thermophilus and B. longum revealed that the freeze-dried and spray-dried fermented soymilk rehydrated at 35-50 degrees C and 20 degrees C, respectively, was optimum for the recovery of the starter organisms. Both S. thermophilus and B. longum survived better in the freeze-dried than the spray-dried fermented soymilk during storage. A higher percent of survival was also noted for both the starter organisms when the dried fermented soymilk was stored at 4 degrees C than 25 degrees C. Holding the dried fermented soymilk in the laminated pouch enabled S. thermophilus and B. longum to exhibit a higher percentage of survival than in the deoxidant- and desiccant-containing glass or polyester (PET) bottle. Among all the packaging materials and storage temperatures tested, starter organisms were most stable in the dried fermented soymilk held in laminated pouch and stored at 4 degrees C. Under this storage condition, S. thermophilus and B. longum showed a survival percentage of 51.1% and 68.8%, respectively, in the freeze-dried fermented soymilk after 4 months of storage. Meanwhile, S. thermophilus and B. infantis in

  17. A model to assess lactic acid bacteria aminopeptidase activities in Parmigiano Reggiano cheese during ripening.

    PubMed

    Gatti, M; De Dea Lindner, J; Gardini, F; Mucchetti, G; Bevacqua, D; Fornasari, M E; Neviani, E

    2008-11-01

    The aim of this work was to investigate in which phases of ripening of Parmigiano Reggiano cheese lactic acid bacteria aminopeptidases present in cheese extract could be involved in release of free amino acids and to better understand the behavior of these enzymes in physical-chemical conditions that are far from their optimum. In particular, we evaluated 6 different substrates to reproduce broad-specificity aminopeptidase N, broad-specificity aminopeptidase C, glutamyl aminopeptidase A, peptidase with high specificity for leucine and alanine, proline iminopeptidase, and X-prolyl dipeptidyl aminopeptidase activities releasing different N-terminal amino acids. The effects of pH, NaCl concentration, and temperature on the enzyme activities of amino acid beta-naphthylamide (betaNA)-substrates were determined by modulating the variables in 19 different runs of an experimental design, which allowed the building of mathematical models able to assess the effect on aminopeptidases activities over a range of values, obtained with bibliographic data, covering different environmental conditions in different zones of the cheese wheel at different aging times. The aminopeptidases tested in this work were present in cell-free Parmigiano Reggiano cheese extract after a 17-mo ripening and were active when tested in model system. The modeling approach shows that to highlight the individual and interactive effects of chemical-physical variables on enzyme activities, it is helpful to determine the true potential of an amino-peptidase in cheese. Our results evidenced that the 6 different lactic acid bacteria peptidases participate in cheese proteolysis and are induced or inhibited by the cheese production parameters that, in turn, depend on the cheese dimension. Generally, temperature and pH exerted the more relevant effects on the enzymatic activities, and in many cases, a relevant interactive effect of these variables was observed. Increasing salt concentration slowed down broad

  18. Abundance of Common Aerobic Anoxygenic Phototrophic Bacteria in a Coastal Aquaculture Area

    PubMed Central

    Sato-Takabe, Yuki; Nakao, Hironori; Kataoka, Takafumi; Yokokawa, Taichi; Hamasaki, Koji; Ohta, Kohei; Suzuki, Satoru

    2016-01-01

    Aerobic anoxygenic phototrophic bacteria (AAnPB) rely on not only heterotrophic but also phototrophic energy gain. AAnPB are known to have high abundance in oligotrophic waters and are the major portion of the bacterial carbon stock in the environment. In a yearlong study in an aquaculture area in the Uwa Sea, Japan, AAnPB, accounted for 4.7 to 24% of the total bacteria by count. Since the cell volume of AAnPB is 2.23 ± 0.674 times larger than the mean for total bacteria, AAnPB biomass is estimated to account for 10–53% of the total bacterial assemblage. By examining pufM gene sequence, a common phylogenetic AAnPB species was found in all sampling sites through the year. The common species and other season-specific species were phylogenetically close to unculturable clones recorded in the Sargasso Sea and Pacific Ocean. The present study suggests that the common species may be a cosmopolitan species with worldwide distribution that is abundant not only in the oligotrophic open ocean but also in eutrophic aquaculture areas. PMID:28018324

  19. Summer community structure of aerobic anoxygenic phototrophic bacteria in the western Arctic Ocean.

    PubMed

    Boeuf, Dominique; Cottrell, Matthew T; Kirchman, David L; Lebaron, Philippe; Jeanthon, Christian

    2013-09-01

    Aerobic anoxygenic phototrophic (AAP) bacteria are found in a range of aquatic and terrestrial environments, potentially playing unique roles in biogeochemical cycles. Although known to occur in the Arctic Ocean, their ecology and the factors that govern their community structure and distribution in this extreme environment are poorly understood. Here, we examined summer AAP abundance and diversity in the North East Pacific and the Arctic Ocean with emphasis on the southern Beaufort Sea. AAP bacteria comprised up to 10 and 14% of the prokaryotic community in the bottom nepheloid layer and surface waters of the Mackenzie plume, respectively. However, relative AAP abundances were low in offshore waters. Environmental pufM clone libraries revealed that AAP bacteria in the Alphaproteobacteria and Betaproteobacteria classes dominated in offshore and in river-influenced surface waters, respectively. The most frequent AAP group was a new uncultivated betaproteobacterial clade whose abundance decreased along the salinity gradient of the Mackenzie plume even though its photosynthetic genes were actively expressed in offshore waters. Our data indicate that AAP bacterial assemblages represented a mixture of freshwater and marine taxa mostly restricted to the Arctic Ocean and highlight the substantial influence of riverine inputs on their distribution in coastal environments.

  20. Characterisation of aerobically grown non-spore-forming bacteria from paper mill pulps containing recycled fibres.

    PubMed

    Suihko, Maija-Liisa; Skyttä, Eija

    2009-01-01

    A total of 179 non-spore-forming bacteria aerobically growing on Nutrient Agar, Plate Count Agar or in specific enrichment conditions for salmonella, campylobacteria, listeria, yersinia or staphylococci, were isolated from 16 untreated paper mill pulps. After phenotypical screening the isolates were characterised by automated ribotyping and partial sequencing of the 16S rRNA gene. They could be divided into seven taxonomical classes representing 63 taxa (species): actinobacteria (11 species), bacilli (7), flavobacteria (3) alphaproteobacteria (10), betaproteobacteria (5), gammaproteobacteria (25) and sphingobacteria (2). Most of the gammaproteobacteria were enterobacteria, mainly species of the genera Enterobacter (7 species, 7 samples/3 mills) and Klebsiella (5 species, 6 samples/3 mills). Other commonly occurring bacteria were most closely related to Microbacterium barkeri (7 samples/3 mills), Cloacibacterium normanense (6 samples/2 mills), Pseudoxanthomonas taiwanensis (5 samples/2 mills) and Sphingobacterium composti (5 samples/1 mill). Sporadic isolates of Listeria innocua, L. monocytogenes, Enterococcus casseliflavus and Staphylococcus warneri were detected, from which only L. monocytogenes is considered to be a food pathogen. No isolates of the genera Campylobacter, Salmonella or Yersinia were detected. The detected bacteria may be harmful in process control, but the load of food pathogens with recycled fibres to paper machines is insignificant. Faecal contamination of the pulp samples was not indicated.

  1. Abundance of Common Aerobic Anoxygenic Phototrophic Bacteria in a Coastal Aquaculture Area.

    PubMed

    Sato-Takabe, Yuki; Nakao, Hironori; Kataoka, Takafumi; Yokokawa, Taichi; Hamasaki, Koji; Ohta, Kohei; Suzuki, Satoru

    2016-01-01

    Aerobic anoxygenic phototrophic bacteria (AAnPB) rely on not only heterotrophic but also phototrophic energy gain. AAnPB are known to have high abundance in oligotrophic waters and are the major portion of the bacterial carbon stock in the environment. In a yearlong study in an aquaculture area in the Uwa Sea, Japan, AAnPB, accounted for 4.7 to 24% of the total bacteria by count. Since the cell volume of AAnPB is 2.23 ± 0.674 times larger than the mean for total bacteria, AAnPB biomass is estimated to account for 10-53% of the total bacterial assemblage. By examining pufM gene sequence, a common phylogenetic AAnPB species was found in all sampling sites through the year. The common species and other season-specific species were phylogenetically close to unculturable clones recorded in the Sargasso Sea and Pacific Ocean. The present study suggests that the common species may be a cosmopolitan species with worldwide distribution that is abundant not only in the oligotrophic open ocean but also in eutrophic aquaculture areas.

  2. Source Tracking and Succession of Kimchi Lactic Acid Bacteria during Fermentation.

    PubMed

    Lee, Se Hee; Jung, Ji Young; Jeon, Che Ok

    2015-08-01

    This study aimed at evaluating raw materials as potential lactic acid bacteria (LAB) sources for kimchi fermentation and investigating LAB successions during fermentation. The bacterial abundances and communities of five different sets of raw materials were investigated using plate-counting and pyrosequencing. LAB were found to be highly abundant in all garlic samples, suggesting that garlic may be a major LAB source for kimchi fermentation. LAB were observed in three and two out of five ginger and leek samples, respectively, indicating that they can also be potential important LAB sources. LAB were identified in only one cabbage sample with low abundance, suggesting that cabbage may not be an important LAB source. Bacterial successions during fermentation in the five kimchi samples were investigated by community analysis using pyrosequencing. LAB communities in initial kimchi were similar to the combined LAB communities of individual raw materials, suggesting that kimchi LAB were derived from their raw materials. LAB community analyses showed that species in the genera Leuconostoc, Lactobacillus, and Weissella were key players in kimchi fermentation, but their successions during fermentation varied with the species, indicating that members of the key genera may have different acid tolerance or growth competitiveness depending on their respective species.

  3. Assessment of probiotic properties in lactic acid bacteria isolated from wine.

    PubMed

    García-Ruiz, Almudena; González de Llano, Dolores; Esteban-Fernández, Adelaida; Requena, Teresa; Bartolomé, Begoña; Moreno-Arribas, M Victoria

    2014-12-01

    Probiotic properties are highly strain-dependent but rarely studied in enological lactic acid bacteria (LAB). In this study, the probiotic features of 11 strains of Lactobacillus spp., Pediococcus spp., and Oenococcus oeni, including saliva and acid resistance, bile tolerance and exopolysaccharides' production, were investigated. The assays included two probiotic reference strains (Lactobacillus plantarum CLC 17 and Lactobacillus fermentum CECT5716). The Lactobacillus and Pediococcus strains showed high resistance to lysozyme (>80% resistance to 100 mg/L of lysozyme under conditions simulating the in vivo dilution by saliva) and were capable of surviving at low pH values (pH 1.8) and bile salts, suggesting good adaptation of the wine strains to gastrointestinal conditions. The ability of the strains to adhere to the intestinal mucosa and the inhibition of the adhesion of Escherichia coli to human intestinal cells were also evaluated. Adhesion levels of enological LAB to Caco-2 cells varied from 0.37% to 12.2%, depending on the strain. In particular, Pediococcus pentosaceus CIAL-86 showed a high percentage of adhesion to intestinal cells (>12%), even higher than that shown by the probiotic reference strains, and a high anti-adhesion activity against E. coli CIAL-153 (>30%), all of which support this wine LAB strain as a potential probiotic.

  4. Development of a method for the direct fermentation of semolina by selected sourdough lactic acid bacteria.

    PubMed

    Alfonzo, Antonio; Urso, Valeria; Corona, Onofrio; Francesca, Nicola; Amato, Gaetano; Settanni, Luca; Di Miceli, Giuseppe

    2016-12-19

    Three obligately heterofermentative lactic acid bacteria (LAB) strains (Lactobacillus sanfranciscensis PON100336, Leuconostoc citreum PON10079 and Weissella cibaria PON10030) were used in this study as a multi-species starter culture for sourdough production. The starter inoculum was prepared and propagated in sterile semolina extract (SSE) broth. Acidification kinetics, microbiological counts detected on specific media for sourdough LAB, polymorphic profile comparison and species-specific PCRs evidenced a stability of the liquid inoculum over time determining its suitability for direct addition to semolina. In order to validate this innovative method for the production of durum wheat (Triticum durum Desf) sourdoughs, 15 semolinas (from ten old and five modern genotypes cultivated in Sicily, southern Italy) were used to prepare the SSEs and to produce sourdoughs and finally breads. Chemical and microbiological analyses of the sourdoughs and the evaluation of the quality parameters (weight loss, height, crumb and crust colour, image analysis and volatile organic compound generation) of the resulting breads indicated that the direct addition of the liquid inocula propagated in SSE is a valuable method to stabilise the production of sourdoughs. The differences registered during the technological characterisation of the breads were underlined by the sensory tests and the multivariate analysis and are mainly imputable to the type of semolina.

  5. Diversity and technological potential of lactic acid bacteria of wheat flours.

    PubMed

    Alfonzo, Antonio; Ventimiglia, Giusi; Corona, Onofrio; Di Gerlando, Rosalia; Gaglio, Raimondo; Francesca, Nicola; Moschetti, Giancarlo; Settanni, Luca

    2013-12-01

    Lactic acid bacteria (LAB) were analysed from wheat flours used in traditional bread making throughout Sicily (southern Italy). Plate counts, carried out in three different media commonly used to detect food and sourdough LAB, revealed a maximal LAB concentration of approximately 4.75 Log CFU g(-1). Colonies representing various morphological appearances were isolated and differentiated based on phenotypic characteristics and genetic analysis by randomly amplified polymorphic DNA (RAPD)-PCR. Fifty unique strains were identified. Analysis by 16S rRNA gene sequencing grouped the strains into 11 LAB species, which belonged to six genera: Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus and Weissella. Weissella cibaria, Lactobacillus plantarum, Leuconostoc pseudomesenteroides and Leuconostoc citreum were the most prevalent species. The strains were not geographically related. Denaturing gradient gel electrophoresis (DGGE) analysis of total DNA of flour was used to provide a more complete understanding of the LAB population; it confirmed the presence of species identified with the culture-dependent approach, but did not reveal the presence of any additional LAB species. Finally, the technological characteristics (acidifying capacity, antimicrobial production, proteolytic activity, organic acid, and volatile organic compound generation) of the 50 LAB strains were investigated. Eleven strains were selected for future in situ applications.

  6. Lactic acid bacteria and yeasts involved in the fermentation ofamabere amaruranu, a Kenyan fermented milk

    PubMed Central

    Nyambane, Bitutu; Thari, William M; Wangoh, John; Njage, Patrick M K

    2014-01-01

    Indigenous fermented milk products contain microbiota composed of technologically important species and strains which are gradually getting lost with new technologies. We investigated the microbial diversity inamabere amaruranu, a traditionally fermented milk product from Kenya. Sixteen samples of the product from different containers were obtained. One hundred and twenty isolates of lactic acid bacteria (LAB) and 67 strains of yeasts were identified using API 50 CH and API 20 C AUX identification kits, respectively. The average pH of all the traditional fermented samples was 4.00 ± 0.93. Lactobacilli, yeasts, and molds as well asEnterobacteriaceae counts from the plastic containers were significantly higher (P < 0.05) than those from gourd.Enterobacteriaceae were below 1.00 ± 1.11 log10 cfu/mL in products from the gourds and 2.17 ± 1.92 log10 cfu/mL from the plastic containers. The LAB species were identified asStreptococcus thermophilus (25%),Lactobacillus plantarum (20%), andLeuconostoc mesenteroides (20%). The predominant yeasts wereSaccharomyces cerevisiae (25%),Trichosporum mucoides (15%),Candida famata (10%), andCandida albicans (10%). The type of vessel used for fermentation had no significant influence on the type of isolated and identified species. The diverse mixture of LAB and yeasts microflora forms a potential consortium for further product innovation inamabere amaruranu and other fermented milk products. PMID:25493187

  7. Lactic acid bacteria in marinades used for modified atmosphere packaged broiler chicken meat products.

    PubMed

    Lundström, Hanna-Saara; Björkroth, Johanna

    2007-03-01

    Lactic acid bacteria (LAB) in some marinades commonly used in Finland for modified atmosphere packaged poultry meat products were enumerated and identified to determine whether the marinades contained LAB species that cause meat spoilage. The concentrations of LAB in 51 marinade samples ranged from less than 100 to 8.0 x 10(5) CFU/ml. Seventeen of the samples produced LAB growth only after enrichment, and in five samples no growth was detected either by direct culturing or enrichment. Eighty-eight randomly selected isolates, 51 from the enumerated plates and 37 from enriched samples, were identified using a database of 16S and 23S rRNA gene HindIII restriction fragment length polymorphism patterns of over 300 type and references LAB strains as operational taxonomic units in numerical analyses. The predominating LAB in the enumerated samples was Lactobacillus plantarum (25 of 51 isolates). Eleven isolates were identified as Lactobacillus paracasei subsp. paracasei, and nine were Lactobacillus parabuchneri. None of these species are considered specific spoilage LAB in marinated modified atmosphere packaged poultry meat products nor have they been reported to dominate in unspoiled late-shelf-life products. These results indicate that even though marinades may contain high numbers of LAB, they are not necessarily sources of specific meat spoilage LAB. Therefore, risks associated with meat quality are not predicted by quantitative enumeration of LAB in marinades.

  8. "Green preservatives": combating fungi in the food and feed industry by applying antifungal lactic acid bacteria.

    PubMed

    Pawlowska, Agata M; Zannini, Emanuele; Coffey, Aidan; Arendt, Elke K

    2012-01-01

    Fungal food spoilage plays a pivotal role in the deterioration of food and feed systems and some of them are also able to produce toxic compounds for humans and animals. The mycotoxins produced by fungi can cause serious health hazards, including cancerogenic, immunotoxic, teratogenic, neurotoxic, nephrotoxic and hepatotoxic effects, and Kashin-Beck disease. In addition to this, fungal spoilage/pathogens are causing losses of marketable quality and hygiene of foodstuffs, resulting in major economic problem throughout the world. Nowadays, food spoilage can be prevented using physical and chemical methods, but no efficient strategy has been proposed so far to reduce the microbial growth ensuring public health. Therefore, lactic acid bacteria (LAB) can play an important role as natural preservatives. The protection of food products using LAB is mainly due to the production of antifungal compounds such as carboxylic acids, fatty acids, ethanol, carbon dioxide, hydrogen peroxide, and bacteriocins. In addition to this, LAB can also positively contribute to the flavor, texture, and nutritional value of food products. This review mainly focuses on the use of LAB for food preservation given their extensive industrial application in a wide range of foods and feeds. The attention points out the several industrial patents concerning the use of antifungal LAB as biocontrol agent against spoilage organisms in different fermented foods and feeds.

  9. Newly isolated lactic acid bacteria with probiotic features for potential application in food industry.

    PubMed

    Divya, Jayakumar Beena; Varsha, Kontham Kulangara; Nampoothiri, Kesavan Madhavan

    2012-07-01

    Five newly isolated lactic acid bacteria were identified as Weissella cibaria, Enterococcus faecium, and three different strains of Lactobacillus plantarum by 16S rRNA sequencing. Essential probiotic requirements of these isolates such as tolerance to phenol, low pH, high sodium chloride, and bile salt concentration were checked. Efficiency in adherence to mucin and hydrophobicity of the bacterial cell were also evaluated by in vitro studies. Antimicrobial activities against some pathogens were tried, and the sensitivity of these strains against 25 different antibiotics was also checked. Further studies revealed Weissella and Enterococcus as substantial producers of folic acid. Folate is involved as a cofactor in many metabolic reactions, and it has to be an essential component in the human diet. The folate level in the fermented samples was determined by microbiological assay using Lactobacillus casei NCIM 2364 as indicator strain. The three strains of L. plantarum showed significant inhibitory activity against various fungi that commonly contaminate food stuffs indicating their potential as a biopreservative of food material.

  10. Evaluation of biodiversity of lactic acid bacteria microbiota in the calf intestinal tracts.

    PubMed

    Busconi, Matteo; Reggi, Serena; Fogher, Corrado

    2008-08-01

    Amplified fragment length polymorphism (AFLPs) were used to analyse the naturally occurring flora of lactic acid bacteria (LAB) in gastrointestinal tracts of two healthy 65-day-old calves. More than 1,000 of presumptive LAB were collected and cultured from the gastrointestinal tracts and, among the isolated colonies, a total of 311 strains were analysed and separated into eight clusters based on AFLP banding patterns. To precisely determine the species inside the clusters, partial sequences of fragments of the 16S ribosomal DNA gene were determined, and sequence homology searches were conducted through GenBank on few strains per cluster. The most representative genera of LAB were Lactobacillus (169 isolates, 54% of total) and Streptococcus (99 isolates, 32% of total), while the most frequent species was identified as L. mucosae with 86 different isolates (51% of the Lactobacillus spp. and 28% of the total). This report gives a first characterization of LAB strain biodiversity recovered directly from calf intestine and is the first account of the presence of the L. mucosae species in calves. Moreover it demonstrates that the AFLP is a robust and useful technique for characterizing the strain level of LAB microflora.

  11. Spoilage characteristics of traditionally packaged ground beef with added lactic acid bacteria displayed at abusive temperatures.

    PubMed

    Hoyle Parks, A R; Brashears, M M; Woerner, W D; Martin, J N; Thompson, L D; Brooks, J C

    2012-02-01

    Growth of pathogenic organisms such as Escherichia coli O157:H7 and Salmonella spp. can be inhibited in ground beef through the addition of certain lactic acid-producing bacteria (LAB; Lactobacillus acidophilus NP51, Lactobacillus crispatus NP35, Pediococcus acidilactici, and Lactococcus lactis ssp. lactis). This study evaluated the effects of LAB inclusion on the organoleptic and biochemical properties typically associated with spoilage in traditionally packaged ground beef displayed at abusive (10°C) temperatures for 36 h. Trained and untrained panelist evaluations of lean color and off-odor, as well as instrumental color analyses, did not indicate an effect on spoilage traits due to LAB utilization (P > 0.05). However, display length affected each variable independently and was indicative of decreased stability and acceptability as display time (h) increased (P < 0.05). Thiobarbituric acid values were decreased for ground beef with added LAB (P < 0.05), but likely can be related to bacterial degradation of lipid oxidation by-products because no reduction in organoleptic traits due to oxidation was noted between treatments. Overall, LAB did not adversely influence the spoilage characteristics of traditionally packaged ground beef displayed at abusive temperatures for up to 36 h. Furthermore, biochemical and sensory indicators of spoilage were present for all treatments at the conclusion of display. Therefore, LAB can be added to ground beef in traditional packaging as a processing intervention without masking or delaying the expected spoilage characteristics.

  12. Enzymatic activity of lactic acid bacteria (with antimicrobial properties) isolated from a traditional Spanish cheese.

    PubMed

    González, Leticia; Sacristán, Noelia; Arenas, Ricardo; Fresno, José M; Eugenia Tornadijo, M

    2010-08-01

    Twenty-four strains of lactic acid bacteria (LAB) isolated from a traditional Spanish cheese (Genestoso cheese) were evaluated for their enzymatic activities (acidifying and proteolytic abilities and carboxypeptidase, aminopeptidase, dipeptidase, caseinolytic and esterase activities), in order to select indigenous strains of technical interest for the manufacture of cheese. These strains were selected on the basis of their antimicrobial activity relative to five reference strains and were identified as Lactococcus lactis subsp. lactis (thirteen strains), Leuconostoc mesenteroides (two strains), Leuconostoc pseudomesenteroides (one strain), Lactobacillus paracasei (two strains), Lactobacillus plantarum (one strain) and Enterococcus faecalis (five strains). Lactococcus strains were those that showed the greatest degree of acidifying and proteolytic activity. The cell-free extracts (CFE) of L. paracasei exhibited the highest level of aminopeptidase activity. The highest level of caseinolytic activity was shown by the CFE of one strain of L. lactis. High values were also obtained with the CFE of Lactobacillus and of several Leuconostoc. The highest level of dipeptidase activity was found amongst the strains of L. lactis. Carboxypeptidase activity was generally very low or undetectable for the majority of strains. The greatest degree of esterolytic activity was detected for Enterococcus.

  13. The Use of Lactic Acid Bacteria as a Probiotic in Swine Diets

    PubMed Central

    Yang, Fengjuan; Hou, Chengli; Zeng, Xiangfang; Qiao, Shiyan

    2015-01-01

    As the resistance of pathogens to antibiotics and the possibility of antibiotic residues in animal products attract increasing attention, the interest in the use of alternatives to in-feed antibiotics has been growing. Recent research with Lactic acid bacteria (LAB) in pigs suggests that LAB provide a potential alternative to antibiotic strategies. LAB include Lactobacillus species, Bifidobacterium spp, Bacillus spp, and some other microbes. LAB can adjust the intestinal environment, inhibit or kill pathogens in the gastrointestinal tract and improve the microbial balance in the intestine, as well as regulate intestinal mucosal immunity and maintain intestinal barrier function, thereby benefiting the health of pigs. The related mechanisms for these effects of LAB may include producing microbicidal substances with effects against gastrointestinal pathogens and other harmful microbes, competing with pathogens for binding sites on the intestinal epithelial cell surface and mucin as well as stimulating the immune system. In this review, the characteristics of LAB and their probiotic effects in newborn piglets, weaned piglets, growing pigs and sows are documented. PMID:25633489

  14. Screening of lactic acid bacteria and bifidobacteria for potential probiotic use in Iberian dry fermented sausages.

    PubMed

    Ruiz-Moyano, Santiago; Martín, Alberto; Benito, María José; Nevado, Francisco Pérez; de Guía Córdoba, María

    2008-11-01

    The purpose of this study was to select lactic acid bacteria and bifibobacteria strains as potential probiotic cultures during the processing of Iberian dry fermented sausages. A total of 1000 strains were isolated from Iberian dry fermented sausages (363), and human (337) and pig faeces (300) in different culture media. Around 30% of these strains, mainly isolated from Iberian dry fermented sausages in LAMVAB agar, were pre-selected for testing as potential probiotics by their ability to grow adequately at the pH values and NaCl concentrations of these meat products during the ripening process. Of the in vitro investigations used to predict the survival of a strain in conditions present in the gastro intestinal tract, exposure to pH 2.5 showed itself to be a highly discriminating factor with only 51 out of 312 pre-selected strains resisting adequately after 1.5h of exposure. All acid-resistant isolates identified as lactobacilli originated from human faeces (Lactobacillus casei and Lactobacillus fermentum) and pig faeces (Lactobacillus reuteri, Lactobacillus animalis, Lactobacillus murinus, and Lactobacillus vaginalis). Pediococcus acidilactici strains were isolated from Iberian dry fermented sausages and pig faeces, whereas the greatest number of Enterococcus strains were identified as Enterococcus faecium, with this species being isolated from Iberian dry fermented sausages, and human and pig faeces. Most of these strains are promising probiotic meat culture candidates suitable for Iberian dry fermented sausages.

  15. Occurrence of biogenic amine-forming lactic acid bacteria in wine and cider.

    PubMed

    Coton, M; Romano, A; Spano, G; Ziegler, K; Vetrana, C; Desmarais, C; Lonvaud-Funel, A; Lucas, P; Coton, E

    2010-12-01

    A collection of 810 lactic acid bacteria (LAB) strains isolated from wine and cider was screened for potential biogenic amine (BA) producers by combining molecular and phenotypic approaches. A newly developed multiplex PCR method allowed for the simultaneous detection of four genes involved in the production of histamine (histidine decarboxylase, hdc), tyramine (tyrosine decarboxylase, tyrdc) and putrescine (via either ornithine decarboxylase, odc, or agmatine deiminase, agdi) while TLC and HPLC analysis allowed for BA-production determination. One hundred and fifty-eight LAB strains were monitored by the molecular/phenotypic double approach and revealed a good correlation between genotypic and phenotypic data. Eighteen per cent of the tested strains were positive for at least one BA target gene with up to three detected simultaneously, in particular amongst Lactobacillus brevis and Lactobacillus hilgardii isolates for the tyrdc and agdi genes. The most frequent gene corresponded to the agdi gene detected in 112 strains (14% of all LAB strains) of 10 different LAB species. The tyrdc gene was detected in 67 strains represented by 7 different LAB species (8% overall), especially those isolated from wine. Lower levels of hdc(+) (2% of strains) and especially odc(+) (0.5% of strains) strains were observed. Interestingly, species that have never been described to carry BA-producing pathway genes were identified in this study. Furthermore, only one cadaverine-producer was detected and corresponded to Lactobacillus 30a, a collection strain not found in fermented beverages, although cadaverine is commonly detected in wines.

  16. Effects of lactic acid bacteria isolated from fermented mustard on lowering cholesterol

    PubMed Central

    Wang, Shu Chen; Chang, Chen Kai; Chan, Shu Chang; Shieh, Jiunn Shiuh; Chiu, Chih Kwang; Duh, Pin-Der

    2014-01-01

    Objective To evaluate the ability of lactic acid bacteria (LAB) strains isolated from fermented mustard to lower the cholesterol in vitro. Methods The ability of 50 LAB strains isolated from fermented mustard on lowering cholesterol in vitro was determined by modified o-phtshalaldehyde method. The LAB isolates were analyzed for their resistance to acid and bile salt. Strains with lowering cholesterol activity, were determined adherence to Caco-2 cells. Results Strain B0007, B0006 and B0022 assimilated more cholesterol than BCRC10474 and BCRC 17010. The isolated strains showed tolerance to pH 3.0 for 3 h despite variations in the degree of viability and bile-tolerant strains, with more than 108 CFU/mL after incubation for 24 h at 1% oxigall in MRS. In addition, strain B0007 and B0022 identified as Lactobacillus plantarum with 16S rDNA sequences were able to adhere to the Caco-2 cell lines. Conclusions These strains B0007 and B0022 may be potential functional sources for cholesterol-lowering activities as well as adhering to Caco-2 cell lines. PMID:25183271

  17. Broad-spectrum antifungal-producing lactic acid bacteria and their application in fruit models.

    PubMed

    Crowley, Sarah; Mahony, Jennifer; van Sinderen, Douwe

    2013-07-01

    A large-scale screen of some 7,000 presumptive lactic acid bacteria (LAB), isolated from animal, human, or plant origin, identified 1,149 isolates with inhibitory activity against the food-spoilage mould Penicillium expansum. In excess of 500 LAB isolates were subsequently identified to produce a broad spectrum of activity against P. expansum, Penicillium digitatum, Penicillium notatum, Penicillium roqueforti, Rhizopus stolonifer, Fusarium culmorum, Aspergillus fumigatus and Rhodotorula mucilaginosa. Partial 16S rRNA sequencing of 94 broad spectrum isolates revealed that the majority of antifungal producers were strains of Lactobacillus plantarum. The remaining population was composed of Weissella confusa and Pediococcus pentosaceous isolates. Characterization of six selected broad-spectrum antifungal LAB isolates revealed that antifungal activity is maximal at a temperature of 30 °C, a pH of 4.0 and is stable across a variety of salt concentrations. The antifungal compound(s) was shown to be neither proteinaceous nor volatile in nature. P. pentosaceous 54 was shown to have protective properties against P. expansum spoilage when applied in pear, plum and grape models, therefore representing an excellent candidate for food-related applications.

  18. Monitoring psychrotrophic lactic acid bacteria contamination in a ready-to-eat vegetable salad production environment.

    PubMed

    Pothakos, Vasileios; Snauwaert, Cindy; De Vos, Paul; Huys, Geert; Devlieghere, Frank

    2014-08-18

    A study monitoring lactic acid bacteria contamination was conducted in a company producing fresh, minimally processed, packaged and ready-to-eat (RTE) vegetable salads (stored at 4°C) in order to investigate the reason for high psychrotrophic LAB levels in the products at the end of shelf-life. Initially, high microbial counts exceeding the established psychrotrophic thresholds (>10(7)-10(8)CFU/g) and spoilage manifestations before the end of the shelf-life (7days) occurred in products containing an assortment of sliced and diced vegetables, but within a one year period these spoilage defects became prevalent in the entire processing plant. Environmental sampling and microbiological analyses of the raw materials and final products throughout the manufacturing process highlighted the presence of high numbers of Leuconostoc spp. in halved and unseeded, fresh sweet bell peppers provided by the supplier. A combination of two DNA fingerprinting techniques facilitated the assessment of the species diversity of LAB present in the processing environment along with the critical point of their introduction in the production facility. Probably through air mediation and surface adhesion, mainly members of the strictly psychrotrophic species Leuconostoc gelidum subsp. gasicomitatum and L. gelidum subsp. gelidum were responsible for the cross-contamination of every vegetable handled within the plant.

  19. Lactic acid bacteria fermentation of human milk oligosaccharide components, human milk oligosaccharides and galactooligosaccharides.

    PubMed

    Schwab, Clarissa; Gänzle, Michael

    2011-02-01

    Human milk contains about 7% lactose and 1% human milk oligosaccharides (HMOs) consisting of lactose with linked fucose, N-acetylglucosamine and sialic acid. In infant formula, galactooligosaccharides (GOSs) are added to replace HMOs. This study investigated the ability of six strains of lactic acid bacteria (LAB), Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus reuteri, Streptococcus thermophilus and Leuconostoc mesenteroides subsp. cremoris, to digest HMO components, defined HMOs, and GOSs. All strains grew on lactose and glucose. N-acetylglucosamine utilization varied between strains and was maximal in L. plantarum; fucose utilization was low or absent in all strains. Both hetero- and homofermentative LAB utilized N-acetylglucosamine via the Embden-Meyerhof pathway. Lactobacillus acidophilus and L. plantarum were the most versatile in hydrolysing pNP analogues and the only strains releasing mono- and disaccharides from defined HMOs. Whole cells of all six LAB hydrolysed oNP-galactoside and pNP-galactoside indicating β-galactosidase activity. High β-galactosidase activity of L. reuteri, L. fermentum, S. thermophilus and L. mesenteroides subsp. cremoris whole cells correlated to lactose and GOS hydrolysis. Hydrolysis of lactose and GOSs by heterologously expressed β-galactosidases confirmed that LAB β-galactosidases are involved in GOS digestion. In summary, the strains of LAB used were not capable of utilizing complex HMOs but metabolized HMO components and GOSs.

  20. Biopolymers from lactic acid bacteria. Novel applications in foods and beverages

    PubMed Central

    Torino, María I.; Font de Valdez, Graciela; Mozzi, Fernanda

    2015-01-01

    Lactic acid bacteria (LAB) are microorganisms widely used in the fermented food industry worldwide. Certain LAB are able to produce exopolysaccharides (EPS) either attached to the cell wall (capsular EPS) or released to the extracellular environment (EPS). According to their composition, LAB may synthesize heteropolysaccharides or homopolysaccharides. A wide diversity of EPS are produced by LAB concerning their monomer composition, molecular mass, and structure. Although EPS-producing LAB strains have been traditionally applied in the manufacture of dairy products such as fermented milks and yogurts, their use in the elaboration of low-fat cheeses, diverse type of sourdough breads, and certain beverages are some of the novel applications of these polymers. This work aims to collect the most relevant issues of the former reviews concerning the monomer composition, structure, and yields and biosynthetic enzymes of EPS from LAB; to describe the recently characterized EPS and to present the application of both EPS-producing strains and their polymers in the fermented (specifically beverages and cereal-based) food industry. PMID:26441845

  1. House microbiotas as sources of lactic acid bacteria and yeasts in traditional Italian sourdoughs.

    PubMed

    Minervini, Fabio; Lattanzi, Anna; De Angelis, Maria; Celano, Giuseppe; Gobbetti, Marco

    2015-12-01

    This study aimed at understanding the extent of contamination by lactic acid bacteria (LAB) and yeasts from the house microbiotas during sourdough back-slopping. Besides sourdoughs, wall, air, storage box, dough mixer and flour of four bakeries were analyzed. Based on plate counts, LAB and yeasts dominated the house microbiota. Based on high throughput sequencing of the 16S rRNA genes, flour harbored the highest number of Firmicutes, but only few of them adapted to storage box, dough mixer and sourdough. Lactobacillus sanfranciscensis showed the highest abundance in dough mixer and sourdoughs. Lactobacillus plantarum persisted only in storage box, dough mixer and sourdough of two bakeries. Weissella cibaria also showed higher adaptability in sourdough than in bakery equipment, suggesting that flour is the main origin of this species. Based on 18S rRNA data, Saccharomyces cerevisiae was the dominant yeast in house and sourdough microbiotas, excepted one bakery dominated by Kazachstania exigua. The results of this study suggest that the dominant species of sourdough LAB and yeasts dominated also the house microbiota.

  2. Diversity of lactic acid bacteria associated with fresh coffee cherries in Taiwan.

    PubMed

    Leong, Kun-hon; Chen, Yi-sheng; Pan, Shwu-fen; Chen, Jen-jye; Wu, Hui-chung; Chang, Yu-chung; Yanagida, Fujitoshi

    2014-04-01

    A total of 102 lactic acid bacteria (LAB) were isolated from three different coffee farms in Taiwan. These isolates were classified and identified by the restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. Heterofermentative Leuconostoc, and Weissella species were the most common LAB found in two farms located at an approximate altitude of 800 m. Lactococcus lactis subsp. lactis was the most common LAB found in the remaining farm was located at an approximate altitude of 1,200 m. It is therefore suggested that the altitude and climate may affect the distribution of LAB. On the basis of phylogenetic analysis, two strains included in the genera Enterococcus were considered as two potential novel species or subspecies. In addition, a total of 34 isolates showed the antifungal activity against Aspergillus flavus. Moreover, seven Lactococcus lactis subsp. lactis strains and one Enterococcus faecalis strain were found to have bacteriocin-like inhibitory substance-producing capability. These results suggest that various LAB are associated with fresh coffee cherries in Taiwan. Some of the isolates found in this study showed potential as antifungal agents.

  3. Uracil as an index of lactic acid bacteria contamination of tomato products.

    PubMed

    Hidalgo, Alyssa; Pompei, Carlo; Galli, Antonietta; Cazzola, Sara

    2005-01-26

    The aim of this research was to evaluate the suitability of uracil as an hygienic quality index of tomato products. Whereas uridine was naturally present throughout tomato fruits' ripening, uracil appeared only after microbial contamination. In tomato pulp inoculated with nine different microbial strains, all five lactic acid bacteria (LAB) studied released relevant quantities of uracil (150-1040 mg/kg of dm), with a correlated partial or total decrease of uridine. Uracil production by yeasts and molds was very low or nonexistent; the starting uridine concentration (approximately 960 mg/kg of dm) remained constant or increased. Uracil thermostability was also verified. Twenty-six samples of tomato paste (30 degrees Brix) were collected from bag-in-drums produced in an industrial processing plant, some with evident swelling symptoms. All of the samples with high microbial count presented uracil. Uracil was also present in samples with microbial contamination under the detection limit and Howard mold count below legislation limits, implying the reprocessing, at least partial, of altered tomato product. The results indicate that uracil presence in tomato products is an index of LAB contamination that has occurred before heat treatment.

  4. Lactic Acid Bacteria as Cell Factories for the Generation of Bioactive Peptides.

    PubMed

    Brown, Lucia; Pingitore, Esteban Vera; Mozzi, Fernanda; Saavedra, Lucila; Villegas, Josefina M; Hebert, Elvira M

    2017-01-01

    There is a growing interest in the incorporation of functional foods in the daily diet to achieve health promotion and disease risk reduction. Numerous studies have focused on the production of biologically active peptides as nutraceuticals and functional food ingredients due to their health benefits. These short peptides, displaying antihypertensive, antioxidant, mineral binding, immunomodulatory and antimicrobial activities are hidden in a latent state within the primary sequences of food proteins requiring enzymatic proteolysis for their release. While microbial fermentation is one of the major and economically most convenient processes used to generate bioactive peptides, lactic acid bacteria (LAB) are widely used as starter cultures for the production of diverse fermented foods. This article reviews the current knowledge on LAB as cell factories for the production of bioactive peptides from a variety of food protein sources. These microorganisms depend on a complex proteolytic system to ensure successful fermentation processes. In the dairy industry, LAB containing cell envelope-associated proteinases (CEPs) are employed as biocatalysts for the first step of casein breakdown releasing bioactive peptides during milk fermentation. A better understanding of the functionality and regulation of the proteolytic system of LAB opens up future opportunities for the production of novel food-derived compounds with potential health-promoting properties.

  5. Transfer of Antibiotic Resistance Marker Genes between Lactic Acid Bacteria in Model Rumen and Plant Environments▿

    PubMed Central

    Toomey, Niamh; Monaghan, Áine; Fanning, Séamus; Bolton, Declan

    2009-01-01

    Three wild-type dairy isolates of lactic acid bacteria (LAB) and one Lactococcus lactis control strain were analyzed for their ability to transfer antibiotic resistance determinants (plasmid or transposon located) to two LAB recipients using both in vitro methods and in vivo models. In vitro transfer experiments were carried out with the donors and recipients using the filter mating method. In vivo mating examined transfer in two natural environments, a rumen model and an alfalfa sprout model. All transconjugants were confirmed by Etest, PCR, pulsed-field gel electrophoresis, and Southern blotting. The in vitro filter mating method demonstrated high transfer frequencies between all LAB pairs, ranging from 1.8 × 10−5 to 2.2 × 10−2 transconjugants per recipient. Transconjugants were detected in the rumen model for all mating pairs tested; however, the frequencies of transfer were low and inconsistent over 48 h (ranging from 1.0 × 10−9 to 8.0 × 10−6 transconjugants per recipient). The plant model provided an environment that appeared to promote comparatively higher transfer frequencies between all LAB pairs tested over the 9-day period (transfer frequencies ranged from 4.7 × 10−4 to 3.9 × 10−1 transconjugants per recipient). In our test models, dairy cultures of LAB can act as a source of mobile genetic elements encoding antibiotic resistance that can spread to other LAB. This observation could have food safety and public health implications. PMID:19270126

  6. Screening of lactic acid bacteria from vacuum packaged beef for antimicrobial activity

    PubMed Central

    Oliveira, Roseane B. P.; de L. Oliveira, Afonso; Glória, M. Beatriz A.

    2008-01-01

    The objective of this study was to isolate lactic acid bacteria (LAB) from vacuum packaged beef and to investigate their antagonist activity. LAB mean counts of 5.19 log cfu/cm2 were obtained from five samples of vacuum packaged beef. Two hundred isolates were selected and screened for the inhibitory effect on five ATCC reference Lactobacillus strains. Thirty six isolates showed activity in the agar spot test against at least two of the indicator strains. However, only six cell free supernatants (CFS) from these isolates exhibited activity against the indicator strains using the well-diffusion test and conditions that eliminated the effects of organic acids and hydrogen peroxide. L. acidophilus was the most sensitive indicator tested, whereas L. plantarum and L. fermentum were the most resistant ones. Identification by MIDI system indicated that these LAB isolates were Lactococcus lactis subsp. cremoris, Pediococcus acidilactici, Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus casei GC subgroup A. The antagonistic factors produced by most of these LAB against L. acidophilus were resistant to heat treatment (100°C for 10 min) and stable over a wide pH range (4.0 to 9.0). These data suggest that these isolates could be used as promising hurdles aiming increased safety and extended shelf life of meat products. PMID:24031232

  7. Use of human lysozyme transgenic goat milk in cheese making: effects on lactic acid bacteria performance.

    PubMed

    Scharfen, E C; Mills, D A; Maga, E A

    2007-09-01

    Genetically engineered goats expressing elevated levels of the antimicrobial enzyme lysozyme in their milk were developed to improve udder health, product shelf life, and consumer well-being. The purpose of this study was to evaluate the effect of lysozyme on the development of lactic acid bacteria (LAB) throughout the cheese-making process. Raw and pasteurized milk from 7 lysozyme transgenic goats and 7 breed-, age-, and parity-matched nontransgenic controls was transformed into cheeses by using industry methods, and their microbiological load was evaluated. The numbers of colony-forming units of LAB were determined for raw and pasteurized goat milk, whey, and curd at d 2 and at d 6 or 7 of production. Selective plating media were used to enumerate lactococcal species separately from total LAB. Although differences in the mean number of colony-forming units between transgenic and control samples in raw milk, whey, and cheese curd were non-significant for both total LAB and lactococcal species from d 2 of production, a significant decrease was observed in both types of LAB among d 6 transgenic raw milk cheese samples. In pasteurized milk trials, a significant decrease in LAB was observed only in the raw milk of transgenic animals. These results indicate that lysozyme transgenic goat milk is not detrimental to LAB growth during the cheese-making process.

  8. Fresh-Cut Pineapple as a New Carrier of Probiotic Lactic Acid Bacteria

    PubMed Central

    Russo, Pasquale; de Chiara, Maria Lucia Valeria; Vernile, Anna; Amodio, Maria Luisa; Arena, Mattia Pia; Capozzi, Vittorio; Massa, Salvatore; Spano, Giuseppe

    2014-01-01

    Due to the increasing interest for healthy foods, the feasibility of using fresh-cut fruits to vehicle probiotic microorganisms is arising scientific interest. With this aim, the survival of probiotic lactic acid bacteria, belonging to Lactobacillus plantarum and Lactobacillus fermentum species, was monitored on artificially inoculated pineapple pieces throughout storage. The main nutritional, physicochemical, and sensorial parameters of minimally processed pineapples were monitored. Finally, probiotic Lactobacillus were further investigated for their antagonistic effect against Listeria monocytogenes and Escherichia coli O157:H7 on pineapple plugs. Our results show that at eight days of storage, the concentration of L. plantarum and L. fermentum on pineapples pieces ranged between 7.3 and 6.3 log cfu g−1, respectively, without affecting the final quality of the fresh-cut pineapple. The antagonistic assays indicated that L. plantarum was able to inhibit the growth of both pathogens, while L. fermentum was effective only against L. monocytogenes. This study suggests that both L. plantarum and L. fermentum could be successfully applied during processing of fresh-cut pineapples, contributing at the same time to inducing a protective effect against relevant foodborne pathogens. PMID:25093163

  9. Symbionts as major modulators of insect health: lactic acid bacteria and honeybees.

    PubMed

    Vásquez, Alejandra; Forsgren, Eva; Fries, Ingemar; Paxton, Robert J; Flaberg, Emilie; Szekely, Laszlo; Olofsson, Tobias C

    2012-01-01

    Lactic acid bacteria (LAB) are well recognized beneficial host-associated members of the microbiota of humans and animals. Yet LAB-associations of invertebrates have been poorly characterized and their functions remain obscure. Here we show that honeybees possess an abundant, diverse and ancient LAB microbiota in their honey crop with beneficial effects for bee health, defending them against microbial threats. Our studies of LAB in all extant honeybee species plus related apid bees reveal one of the largest collections of novel species from the genera Lactobacillus and Bifidobacterium ever discovered within a single insect and suggest a long (>80 mya) history of association. Bee associated microbiotas highlight Lactobacillus kunkeei as the dominant LAB member. Those showing potent antimicrobial properties are acquired by callow honey bee workers from nestmates and maintained within the crop in biofilms, though beekeeping management practices can negatively impact this microbiota. Prophylactic practices that enhance LAB, or supplementary feeding of LAB, may serve in integrated approaches to sustainable pollinator service provision. We anticipate this microbiota will become central to studies on honeybee health, including colony collapse disorder, and act as an exemplar case of insect-microbe symbiosis.

  10. Short communication: Lactic acid bacteria from the honeybee inhibit the in vitro growth of mastitis pathogens.

    PubMed

    Piccart, K; Vásquez, A; Piepers, S; De Vliegher, S; Olofsson, T C

    2016-04-01

    Despite the increasing knowledge of prevention and control strategies, bovine mastitis remains one of the most challenging diseases in the dairy industry. This study investigated the antimicrobial activity of 13 species of lactic acid bacteria (LAB), previously isolated from the honey crop of the honeybee, on several mastitis pathogens. The viable LAB were first reintroduced into a sterilized heather honey matrix. More than 20 different bovine mastitis isolates were tested against the mixture of the 13 LAB species in the honey medium using a dual-culture overlay assay. The mastitis isolates were identified through bacteriological culturing, followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Additionally, the mastitis isolates were subjected to antimicrobial susceptibility testing through disk diffusion. Growth of all tested mastitis pathogens, including the ones displaying antimicrobial resistance to one or more antimicrobial compounds, were inhibited to some extent by the honey and LAB combination. The antibacterial effect of these LAB opens up new perspectives on alternative treatment and prevention of bovine mastitis.

  11. Isolation and characteristics of lactic acid bacteria isolated from ripe mulberries in Taiwan

    PubMed Central

    Chen, Yi-sheng; Wu, Hui-chung; Yanagida, Fujitoshi

    2010-01-01

    The objective of this study was to isolate, characterize, and identify lactic acid bacteria (LAB) from ripe mulberries collected in Taiwan. Ripe mulberry samples were collected at five mulberry farms, located in different counties of Taiwan. Eighty-eight acid-producing cultures were isolated from these samples, and isolates were divided into classes first by phenotype, then into groups by restriction fragment length polymorphism (RFLP) analysis and sequencing of 16S ribosomal DNA (rDNA). Phenotypic and biochemical characteristics led to identification of four bacterial groups (A to D). Weissella cibaria was the most abundant type of LAB distributed in four mulberry farms, and Lactobacillus plantarum was the most abundant LAB found in the remaining farm. Ten W. cibaria and one Lactococcus lactis subsp. lactis isolate produced bacteriocins against the indicator strain Lactobacillus sakei JCM 1157T. These results suggest that various LAB are distributed in ripe mulberries and W. cibaria was the most abundant LAB found in this study. PMID:24031571

  12. Bacteriocins from lactic acid bacteria and their applications in meat and meat products.

    PubMed

    Woraprayote, Weerapong; Malila, Yuwares; Sorapukdee, Supaluk; Swetwiwathana, Adisorn; Benjakul, Soottawat; Visessanguan, Wonnop

    2016-10-01

    Meat and meat products have always been an important part of human diet, and contain valuable nutrients for growth and health. Nevertheless, they are perishable and susceptible to microbial contamination, leading to an increased health risk for consumers as well as to the economic loss in meat industry. The utilization of bacteriocins produced by lactic acid bacteria (LAB) as a natural preservative has received a considerable attention. Inoculation of bacteriocin-producing LAB cell as starter or protective cultures is suitable for fermented meats, whilst the direct addition of bacteriocin as food additive is more preferable when live cells of LAB could not produce bacteriocin in the real meat system. The incorporation of bacteriocins in packaging is another way to improve meat safety to avoid direct addition of bacteriocin to meat. Utilization of bacteriocins can effectively contribute to food safety, especially when integrated into hurdle concepts. In this review, LAB bacteriocins and their applications in meat and meat products are revisited. The molecular structure and characteristics of bacteriocins recently discovered, as well as exemplary properties are also discussed.

  13. Potential of lactic acid bacteria at regulating Escherichia coli infection and inflammation of bovine endometrium.

    PubMed

    Genís, Sandra; Bach, Àlex; Fàbregas, Francesc; Arís, Anna

    2016-03-01

    About 40% of dairy cattle develop uterine disease during postpartum period, causing infertility. Some studies indicate that uterine infection, predominantly by Escherichia coli in the first week postpartum, is associated with metritis, an uterus inflammation in which the cow fails to completely clear bacterial contaminants. The aim of this study was to evaluate the potential of four lactic acid bacteria (LAB) (Lactobacillus rhamnosus, Pediococcus acidilactici, Lactobacillus reuteri, and Lactobacillus sakei) to modulate the E coli infection and inflammation in endometrial cells. Primary endometrial epithelial cells were isolated from fresh endometrium of a healthy cow and cultured in vitro to evaluate the effects of LAB at three different doses. Cell extracts were obtained to analyze the expression of proinflammatory cytokines and to quantify E coli infection on MacConkey agar plates. L sakei and L reuteri showed a positive effect preventing E coli infection (87% and 78%, respectively, P < 0.001); however, they were also associated to a dose-variable effect on tissular inflammation that could further exacerbate the proinflammatory status. Infection of E coli was clearly reduced (P < 0.001) up to an 83% with P acidilactici, whereas, the expression of proinflammatory cytokines IL-8 and IL-1β dropped significantly (P < 0.001) up to 85.11 and 5.24 folds, respectively, in the presence of L rhamnosus. In conclusion, these results demonstrate a clear potential of some LAB in the modulation of endometrial infection and inflammation in cattle.

  14. Design of a Protein-Targeting System for Lactic Acid Bacteria

    PubMed Central

    Dieye, Y.; Usai, S.; Clier, F.; Gruss, A.; Piard, J.-C.

    2001-01-01

    We designed an expression and export system that enabled the targeting of a reporter protein (the staphylococcal nuclease Nuc) to specific locations in Lactococcus lactis cells, i.e., cytoplasm, cell wall, or medium. Optimization of protein secretion and of protein cell wall anchoring was performed with L. lactis cells by modifying the signals located at the N and C termini, respectively, of the reporter protein. Efficient translocation of precursor (∼95%) is obtained using the signal peptide from the lactococcal Usp45 protein and provided that the mature protein is fused to overall anionic amino acids at its N terminus; those residues prevented interactions of Nuc with the cell envelope. Nuc could be covalently anchored to the peptidoglycan by using the cell wall anchor motif of the Streptococcus pyogenes M6 protein. However, the anchoring step proved to not be totally efficient in L. lactis, as considerable amounts of protein remained membrane associated. Our results may suggest that the defect is due to limiting sortase in the cell. The optimized expression and export vectors also allowed secretion and cell wall anchoring of Nuc in food-fermenting and commensal strains of Lactobacillus. In all strains tested, both secreted and cell wall-anchored Nuc was enzymatically active, suggesting proper enzyme folding in the different locations. These results provide the first report of a targeting system in lactic acid bacteria in which the final location of a protein is controlled and biological activity is maintained. PMID:11418555

  15. Changes in satiety hormone concentrations and feed intake in rats in response to lactic acid bacteria.

    PubMed

    Forssten, Sofia D; Korczyńska, Marta Z; Zwijsen, Renate M L; Noordman, Wouter H; Madetoja, Mari; Ouwehand, Arthur C

    2013-12-01

    A negative energy balance can be accomplished by reducing the caloric intake which results in an increased feeling of hunger. This physiological state is regulated by secretion of satiety hormones. The secretion of these hormones can be influenced by ingestion of e.g. fat. Fat, dairy beverage and synbiotic mixture have been found to have satiety-inducing effects in humans and rats. Thus, the aim of this study was to investigate the change of satiety hormone concentration in rats in response to feeding of fermented milks containing lactic acid bacteria. Two studies were conducted with Wistar rats randomly allocated into groups receiving Lactobacillus fermented (2 L. acidophilus, L. bulgaricus, L. salivarius and L. rhamnosus) milk. A single isocaloric oral dose with the test item or control was given to the rats. Blood samples were taken after dosing with the test product and the satiety hormones were measured. For the test groups, significant changes could be detected in PYY concentrations after 60 min, although some groups had a significant lower feed intake. In conclusion, some probiotic Lactobacillus strains may modify satiety hormones production. However, more studies are needed to evaluate their potential of prolonging satiety.

  16. Symbionts as Major Modulators of Insect Health: Lactic Acid Bacteria and Honeybees

    PubMed Central

    Vásquez, Alejandra; Forsgren, Eva; Fries, Ingemar; Paxton, Robert J.; Flaberg, Emilie; Szekely, Laszlo

    2012-01-01

    Lactic acid bacteria (LAB) are well recognized beneficial host-associated members of the microbiota of humans and animals. Yet LAB-associations of invertebrates have been poorly characterized and their functions remain obscure. Here we show that honeybees possess an abundant, diverse and ancient LAB microbiota in their honey crop with beneficial effects for bee health, defending them against microbial threats. Our studies of LAB in all extant honeybee species plus related apid bees reveal one of the largest collections of novel species from the genera Lactobacillus and Bifidobacterium ever discovered within a single insect and suggest a long (>80 mya) history of association. Bee associated microbiotas highlight Lactobacillus kunkeei as the dominant LAB member. Those showing potent antimicrobial properties are acquired by callow honey bee workers from nestmates and maintained within the crop in biofilms, though beekeeping management practices can negatively impact this microbiota. Prophylactic practices that enhance LAB, or supplementary feeding of LAB, may serve in integrated approaches to sustainable pollinator service provision. We anticipate this microbiota will become central to studies on honeybee health, including colony collapse disorder, and act as an exemplar case of insect-microbe symbiosis. PMID:22427985

  17. Identification of lactic acid bacteria isolated from wine using real-time PCR.

    PubMed

    Kántor, Attila; Kluz, Maciej; Puchalski, Czeslaw; Terentjeva, Margarita; Kačániová, Miroslava

    2016-01-01

    Different lactic acid bacteria strains have been shown to cause wine spoilage, including the generation of substances undesirable for the health of wine consumers. The aim of this study was to investigate the occurrence of selected species of heterofermentative lactobacilli, specifically Lactobacillus brevis, Lactobacillus hilgardii, and Lactobacillus plantarum in six different Slovak red wines following the fermentation process. In order to identify the dominant Lactobacillus strain using quantitative (real time) polymerized chain reaction (qPCR) method, pure lyophilized bacterial cultures from the Czech Collection of Microorganisms were used. Six different red wine samples following malolactic fermentation were obtained from selected wineries. After collection, the samples were subjected to a classic plate dilution method for enumeration of lactobacilli cells. Real-time PCR was performed after DNA extraction from pure bacterial strains and wine samples. We used SYBR® Green master mix reagents for measuring the fluorescence in qPCR. The number of lactobacilli ranged from 3.60 to 5.02 log CFU mL(-1). Specific lactobacilli strains were confirmed by qPCR in all wine samples. The number of lactobacilli ranged from 10(3) to 10(6) CFU mL(-1). A melting curve with different melting temperatures (T(m)) of DNA amplicons was obtained after PCR for the comparison of T(m) of control and experimental portions, revealing that the most common species in wine samples was Lactobacillus plantarum with a T(m) of 84.64°C.

  18. Characterization of lactic acid bacteria isolated from Bukuljac, a homemade goat's milk cheese.

    PubMed

    Nikolic, Milica; Terzic-Vidojevic, Amarela; Jovcic, Branko; Begovic, Jelena; Golic, Natasa; Topisirovic, Ljubisa

    2008-02-29

    The Bukuljac cheese is traditionally homemade cheese, produced from heat-treated goat's milk without the addition of any bacterial starter culture. The presence of lactic acid bacteria (LAB) in Bukuljac cheese has been analyzed by using a polyphasic approach including microbiological and molecular methods such as rep-PCR with (GTG)5 primer. Lactobacillus paracasei subsp. paracasei represents a dominant strain in the microflora of analyzed cheese. Out of 55 Gram-positive and catalase-negative isolates, 48 belonged to L. paracasei subsp. paracasei species. Besides lactobacilli, five Lactococcus lactis subsp. lactis and two Enterococcus faecalis were found. Results of PCR-denaturing gradient gel electrophoresis (DGGE) of DNA extracted directly from the fresh cheese revealed the presence of Leuconostoc mesenteroides. Only lactobacilli showed a high proteolytic activity and hydrolyzed alpha(s1)- and beta-caseins. They are also producers of diacetyl. In addition, 34 out of 55 isolates, all determined as lactobacilli, showed the ability of auto-aggregation. Among 55 isolates, 50 also exhibited antimicrobial activity.

  19. Genetic and Technological Characterisation of Vineyard- and Winery-Associated Lactic Acid Bacteria

    PubMed Central

    Nisiotou, Aspasia A.; Filippousi, Maria-Evangelia; Fragkoulis, Petros; Tassou, Chryssoula; Banilas, Georgios

    2015-01-01

    Vineyard- and winery-associated lactic acid bacteria (LAB) from two major PDO regions in Greece, Peza and Nemea, were surveyed. LAB were isolated from grapes, fermenting musts, and winery tanks performing spontaneous malolactic fermentations (MLF). Higher population density and species richness were detected in Nemea than in Peza vineyards and on grapes than in fermenting musts. Pediococcus pentosaceus and Lactobacillus graminis were the most abundant LAB on grapes, while Lactobacillus plantarum dominated in fermenting musts from both regions. No particular structure of Lactobacillus plantarum populations according to the region of origin was observed, and strain distribution seems random. LAB species diversity in winery tanks differed significantly from that in vineyard samples, consisting principally of Oenococcus oeni. Different strains were analysed as per their enological characteristics and the ability to produce biogenic amines (BAs). Winery-associated species showed higher resistance to low pH, ethanol, SO2, and CuSO4 than vineyard-associated isolates. The frequency of BA-producing strains was relatively low but not negligible, considering that certain winery-associated Lactobacillus hilgardii strains were able to produce BAs. Present results show the necessity of controlling the MLF by selected starters in order to avoid BA accumulation in wine. PMID:25866789

  20. Anti-Listeria Activity of Lactic Acid Bacteria in Two Traditional Sicilian Cheeses

    PubMed Central

    Scatassa, Maria Luisa; Gaglio, Raimondo; Cardamone, Cinzia; Macaluso, Giusi; Arcuri, Luigi; Todaro, Massimo; Mancuso, Isabella

    2017-01-01

    Listeria monocytogenes is a pathogen frequently found in dairy products, and its growth is difficult to control. Bacteriocin-like inhibitory substances (BLIS), produced by lactic acid bacteria (LAB), having proven in vitro anti-Listeria activity, could provide an innovative approach to control L. monocytogenes; however, this application needs to be evaluated in vivo. In this study, twenty LAB strains isolated from different Sicilian dairy environments were tested for control of growth of L. monocytogenes in three different experimental trials. First, raw and UHT milk were inoculated with LAB strains alone, and LAB strains mixed with L. monocytogenes. Second, mini-cheeses containing LAB and/or L. monocytogenes were produced. Third, two traditional Sicilian cheeses inoculated with a multi-strain LAB mixture combined with L. monocytogenes were produced. The addition of BLIS produced by LAB to milk and in mini-cheese production was unable to inhibit the growth of L. monocytogenes. However, an anti-Listeria effect was observed in the Pecorino Siciliano cheeses, where, after 15 days of ripening, the cheeses with added LAB had fewer L. monocytogenes compared to the control cheeses with no added LAB, while in the Vastedda della valle del Belìce cheeses, the multi-strain LAB mixture completely prevented the growth of L. monocytogenes. PMID:28299290

  1. Binding and detoxification of chlorpyrifos by lactic acid bacteria on rice straw silage fermentation.

    PubMed

    Wang, Yan-Su; Wu, Tian-Hao; Yang, Yao; Zhu, Cen-Ling; Ding, Cheng-Long; Dai, Chuan-Chao

    2016-01-01

    This investigation examined the reduction of pesticide residues on straw inoculated with lactic acid bacteria (LAB) during ensiling. Lactobacillus casei WYS3 was isolated from rice straw that contained pesticide residues. Non-sterilized rice straw, which was inoculated with L. casei WYS3, showed increased removal of chlorpyrifos after ensiling, compared with rice straw that was not inoculated with L. casei WYS3 or sterilized rice straw. In pure culture, these strains can bind chlorpyrifos as indicated by high-performance liquid chromatography analysis. Viable L. casei WYS3 was shown to bind 33.3-42% of exogenously added chlorpyrifos. These results are similar to those of acid-treated cells but less than those of heat-treated cells, which were found to bind 32.0% and 77.2% of the added chlorpyrifos respectively. Furthermore, gas chromatography-mass spectrometry analysis determined that L. casei WYS3 detoxified chlorpyrifos via P-O-C cleavage. Real-time polymerized chain reaction analysis determined that organophosphorus hydrolase gene expression tripled after the addition of chlorpyrifos to LAB cultures, compared with the control group (without chlorpyrifos). This paper highlights the potential use of LAB starter cultures for the detoxification and removal of chlorpyrifos residues in the environment.

  2. Diversity of bacteriocinogenic lactic acid bacteria isolated from Mediterranean fish viscera.

    PubMed

    Migaw, Sarra; Ghrairi, Taoufik; Belguesmia, Yanath; Choiset, Yvan; Berjeaud, Jean-Marc; Chobert, Jean-Marc; Hani, Khaled; Haertlé, Thomas

    2014-04-01

    Nine lactic acid bacteria strains showing bacteriocin-like activity were isolated from various fresh fish viscera. The following species were identified based on 16S rDNA sequences: Enterococcus durans (7 isolates), Lactococcus lactis (1) and Enterococcus faecium (1). These strains were active against Listeria innocua and other LAB. Random amplified polymorphic DNA analyses showed four major patterns for the E. durans species. PCR analyses revealed a nisin gene in the genome of the Lc. lactis strain. Genes coding enterocins A, B and P were found in the genome of the E. faecium isolate. Enterocins A and B genes were also present in the genome of E. durans GM19. Hence, this is the first report describing E. durans strains producing enterocins A and B. Electrospray ionization mass spectrometry revealed that the purified bacteriocin produced by the E. durans GMT18 strain had an exact molecular mass of 6,316.89 Da. This bacteriocin was designated as durancin GMT18. Edman sequencing failed to proceed; suggesting that durancin GTM18 may contain terminal lanthionine residues. Overall, the results obtained revealed the presence of a variety of enterococci in Mediterranean fish viscera, as evidenced by their genetic profiles and abilities to produce different bacteriocins. These strains could be useful for food biopreservation or as probiotics.

  3. Biopreservation of Brined Shrimp (Pandalus borealis) by Bacteriocins from Lactic Acid Bacteria.

    PubMed

    Einarsson, H; Lauzon, H L

    1995-02-01

    In brined shrimp (ca. 3% NaCl), the effects of three different lactic acid bacteria bacteriocins (crude [6.54 x 10(sup10) U of bacteriocin activity {BU}/g] and purified [8.13 x 10(sup23) BU/g] nisin Z, carnocin UI49 [2.32 x 10(sup4) BU/g], and crude bavaricin A [2.78 BU/g]) on bacterial growth and shelf life were compared with those of a benzoate-sorbate solution (0.1% each [wt/wt]) and a control with no preservatives. The shelf life of shrimp subjected to the control treatment was found to be 10 days. Carnocin UI49 did not extend the shelf life, while crude bavaricin A (a cell-free supernatant of Lactobacillus bavaricus MI 401) resulted in a shelf life of 16 days, as opposed to 31 days with nisin Z for both its crude and purified forms. The benzoate-sorbate solution preserved the brined shrimp for the whole storage period (59 days). In the control, carnocin UI49, and crude bavaricin A treatments, a gram-positive flora dominated towards the end of the storage period while in the nisin Z treatment a gram-negative flora was more pronounced.

  4. Genetic diversity and some aspects of antimicrobial activity of lactic acid bacteria isolated from goat milk.

    PubMed

    Cavicchioli, Valéria Quintana; Dornellas, Wesley Dos Santos; Perin, Luana Martins; Pieri, Fábio Alessandro; Franco, Bernadette Dora Gombossy de Melo; Todorov, Svetoslav Dimitrov; Nero, Luís Augusto

    2015-03-01

    Lactic acid bacteria (LAB, n = 57) were previously obtained from raw goat milk, identified as Lactococcus spp. (n = 24) and Enterococcus spp. (n = 33), and characterized as bacteriocinogenic. Fingerprinting by pulsed field gel electrophoresis (PFGE) demonstrated high genetic diversity, and 30 strains were selected and exhibited strong antimicrobial activity against 46 target strains (LAB, spoilage, and foodborne pathogens). Six strains (Lactococcus lactis: GLc03 and GLc05; and Enterococcus durans: GEn09, GEn12, GEn14, and GEn17) were selected to characterize their bacteriocinogenic features, using Listeria monocytogenes ATCC 7644 as the target. The six strains produced bacteriocins at higher titer when incubated in MRS at 37 °C up to 12 h, when compared to growth at 25 and 30 °C. The produced bacteriocins kept their antimicrobial activity after exposure to 100 °C for 2 h and 121 °C for 20 min; the antimicrobial activity was also observed after treatment at pH 2.0 to 10.0, except for GLc03. L. monocytogenes populations were reduced approximately two logs after treatment with cell-free supernatants from the selected strains. These data show that goat milk can contain a diverse microbiota able to inhibit L. monocytogenes, a common pathogen found in dairy products, and can be potentially employed in biopreservation of food produced under different processing conditions.

  5. Cereal fungal infection, mycotoxins, and lactic acid bacteria mediated bioprotection: from crop farming to cereal products.

    PubMed

    Oliveira, Pedro M; Zannini, Emanuele; Arendt, Elke K

    2014-02-01

    Lactic acid bacteria (LAB) metabolites are a reliable alternative for reducing fungal infections pre-/post-harvest with additional advantages for cereal-base products which convene the food market's trend. Grain industrial use is in expansion owing to its applicability in generating functional food. The food market is directed towards functional natural food with clear health benefits for the consumer in detriment to chemical additives. The food market chain is becoming broader and more complex, which presents an ever-growing fungal threat. Toxigenic and spoilage fungi are responsible for numerous diseases and economic losses. Cereal infections may occur in the field or post-processing, along the food chain. Consequently, the investigation of LAB metabolites with antifungal activity has gained prominence in the scientific research community. LAB bioprotection retards the development of fungal diseases in the field and inhibit pathogens and spoilage fungi in food products. In addition to the health safety improvement, LAB metabolites also enhance shelf-life, organoleptic and texture qualities of cereal-base foods. This review presents an overview of the fungal impact through the cereal food chain leading to investigation on LAB antifungal compounds. Applicability of LAB in plant protection and cereal industry is discussed. Specific case studies include Fusarium head blight, malting and baking.

  6. Risk assessment of genetically modified lactic acid bacteria using the concept of substantial equivalence.

    PubMed

    LeBlanc, Jean Guy; Van Sinderen, Douwe; Hugenholtz, Jeroen; Piard, Jean-Christophe; Sesma, Fernando; de Giori, Graciela Savoy

    2010-12-01

    The use of food-grade microorganisms such as lactic acid bacteria (LAB) is one of the most promising methods for delivering health promoting compounds. Since it is not always possible to obtain strains that have the ability to produce specific compounds naturally or that produce them in sufficient quantities to obtain physiological responses, genetic modifications can be performed to improve their output. The objective of this study was to evaluate if previously studied genetically modified LAB (GM-LAB), with proven in vivo beneficial effects, are just as safe as the progenitor strain from which they were derived. Mice received an elevated concentration of different GM-LAB or the native parental strain from which they were derived during a prolonged period of time, and different health parameters were evaluated. Similar growth rates, hematological values, and other physiological parameters were obtained in the animals that received the GM-LAB compared to those that were fed with the native strain. These results demonstrate that the GM-LAB used in this study are just as safe as the native strains from which they were derived and thus merit further studies to include them into the food chain.

  7. Combined effect of sourdough lactic acid bacteria and additives on bread firmness and staling.

    PubMed

    Corsetti, A; Gobbetti, M; De Marco, B; Balestrieri, F; Paoletti, F; Russi, L; Rossi, J

    2000-07-01

    The effect of various sourdoughs and additives on bread firmness and staling was studied. Compared to the bread produced with Saccharomyces cerevisiae 141, the chemical acidification of dough fermented by S. cerevisiae 141 or the use of sourdoughs increased the volume of the breads. Only sourdough fermentation was effective in delaying starch retrogradation. The effect depended on the level of acidification and on the lactic acid bacteria strain. The effect of sourdough made of S. cerevisiae 141-Lactobacillus sanfranciscensis 57-Lactobacillus plantarum 13 was improved when fungal alpha-amylase or amylolytic strains such as L. amylovorus CNBL1008 or engineered L. sanfranciscensis CB1 Amy were added. When pentosans or pentosans, endoxylanase enzyme, and L. hilgardii S32 were added to the same sourdough, a greater delay of the bread firmness and staling was found. When pentosans were in part hydrolyzed by the endoxylanase enzyme, the bread also had the highest titratable acidity, due to the fermentation of pentoses by L. hilgardii S32. The addition of the bacterial protease to the sourdough increased the bread firmness and staling.

  8. Inhibition of Staphylococcus aureus by crude and fractionated extract from lactic acid bacteria.

    PubMed

    Wong, C-B; Khoo, B-Y; Sasidharan, S; Piyawattanametha, W; Kim, S H; Khemthongcharoen, N; Ang, M-Y; Chuah, L-O; Liong, M-T

    2015-03-01

    Increasing levels of antibiotic resistance by Staphylococcus aureus have posed a need to search for non-antibiotic alternatives. This study aimed to assess the inhibitory effects of crude and fractionated cell-free supernatants (CFS) of locally isolated lactic acid bacteria (LAB) against a clinical strain of S. aureus. A total of 42 LAB strains were isolated and identified from fresh vegetables, fresh fruits and fermented products prior to evaluation of inhibitory activities. CFS of LAB strains exhibiting a stronger inhibitive effect against S. aureus were fractionated into crude protein, polysaccharide and lipid fractions. Crude protein fractions showed greater inhibition against S. aureus compared to polysaccharide and lipid fractions, with a more prevalent effect from Lactobacillus plantarum 8513 and L. plantarum BT8513. Crude protein, polysaccharide and lipid fractions were also characterised with glycine, mannose and oleic acid being detected as the major component of each fraction, respectively. Scanning electron microscopy revealed roughed and wrinkled membrane morphology of S. aureus upon treatment with crude protein fractions of LAB, suggesting an inhibitory effect via the destruction of cellular membrane. This research illustrated the potential application of fractionated extracts from LAB to inhibit S. aureus for use in the food and health industry.

  9. Evaluation of mono or mixed cultures of lactic acid bacteria in type II sourdough system.

    PubMed

    Ekinci, Raci; Şimşek, Ömer; Küçükçuban, Ayca; Nas, Sebahattin

    2016-01-01

    The aim of this study was to evaluate the use of mono and mixed lactic acid bacteria (LAB) cultures to determine suitable LAB combinations for a type II sourdough system. In this context, previously isolated sourdough LAB strains with antimicrobial activity, which included Lactobacillus plantarum PFC22, Lactobacillus brevis PFC31, Pediococcus acidilactici PFC38, and Lactobacillus sanfranciscensis PFC80, were used as mono or mixed culture combinations in a fermentation system to produce type II sourdough, and subsequently in bread dough production. Compared to the monoculture fermentation of dough, the use of mixed cultures shortened the adaptation period by half. In addition, the use of mixed cultures ensured higher microbial viability, and enhanced the fruity flavor during bread dough production. It was determined that the combination of L. plantarum PFC22 + P. acidilactici PFC38 + L. sanfranciscensis PFC80 is a promising culture mixture that can be used in the production of type II sourdough systems, and that may also contribute to an increase in metabolic activity during bread production process.

  10. Inactivation of calcium-dependent lactic acid bacteria phages by phosphates.

    PubMed

    Suárez, V B; Capra, M L; Rivera, M; Reinheimer, J A

    2007-06-01

    The capacity of three phosphates to interrupt the lytic cycle of four specific autochthonal bacteriophages of lactic acid bacteria used as starters was assayed. The phosphates used (polyphosphates A and B and sodium tripolyphosphate-high solubility [TAS]) were selected on the basis of their capacity to sequester divalent cations, which are involved in the lytic cycle of certain bacteriophages. The assays were performed in culture media (deMan Rogosa Sharpe and Elliker broths) and reconstituted (10%, wt/vol) commercial skim milk to which phosphates had been added at concentrations of 0.1, 0.3, and 0.5% (wt/vol). Phosphate TAS was the most inhibitory one, since it was able to inhibit the lytic cycle of all bacteriophages studied, in both broths and milk. In broth, polyphosphates A and B inhibited the lytic cycle of only two bacteriophages at the maximal concentration used (0.5%), whereas in milk, they were not capable of maintaining the same inhibitory effect.

  11. Evolution and identification of lactic acid bacteria isolated during the ripening of Sardinian sausages.

    PubMed

    Greco, M; Mazzette, R; De Santis, E P L; Corona, A; Cosseddu, A M

    2005-04-01

    Lactic acid bacteria (LAB) were isolated during the production and the ripening of Sardinian sausage, a typical Italian dry fermented sausage. Samples were taken at different stages, and 112 strains were isolated. The isolates were characterized using the micromethod proposed by Font de Valdez et al. [Font de Valdez, G., Savoy de Giori, G., Oliver, G., & De Ruiz Holgado, A. P. (1993). Development and optimization of an expensive microsystem for the biochemical characterization of lactobacilli. Microbiologie Aliments Nutrition, 11, 215-219]. Schillinger and Lücke's [Schillinger, U., & Lücke, F. K. (1987). Identification of lactobacilli from meat and meat products. Food Microbiology. (4), 199-208] scheme and the biochemical patterns given by Bergey's Manual of Systematic Bacteriology [Bergey's Manual of Systematic Bacteriology (1986). Baltimore: William and Wilkins] were used for preliminary identification. A PCR-based method was then used to confirm the results. LAB were the dominant flora during ripening. They consisted mainly of homofermentative mesophilic rods. Lactobacillus sakei (43,3%), Lactobacillus plantarum (16,6%) and Lactobacillus curvatus (13,3%) were the main isolates. The results of the biochemical identification methods agreed well with those of PCR-based identification (91% agreement).

  12. Lactic acid bacteria in the prevention of pneumococcal respiratory infection: future opportunities and challenges.

    PubMed

    Villena, Julio; Oliveira, Maria Leonor S; Ferreira, Patricia C D; Salva, Susana; Alvarez, Susana

    2011-11-01

    Lactic acid bacteria (LAB) are technologically and commercially important and have various beneficial effects on human health. Several studies have demonstrated that certain LAB strains can exert their beneficial effect on the host through their immunomudulatory activity. Although most research concerning LAB-mediated enhanced immune protection is focused on gastrointestinal tract pathogens, recent studies have centered on whether these immunobiotics might sufficiently stimulate the common mucosal immune system to provide protection to other mucosal sites as well. In this sense, LAB have been used for the development of probiotic foods with the ability to stimulate respiratory immunity, which would increase resistance to infections, even in immunocompromised hosts. On the other hand, the advances in the molecular biology of LAB have enabled the development of recombinant strains expressing antigens from respiratory pathogens that have proved effective to induce protective immunity. In this review we examine the current scientific literature concerning the use of LAB strains to prevent respiratory infections. In particular, we have focused on the works that deal with the capacity of probiotic and recombinant LAB to improve the immune response against Streptococcus pneumoniae. Research from the last decade demonstrates that LAB represent a promising resource for the development of prevention strategies against respiratory infections that could be effective tools for medical application.

  13. Isolation of Lactic Acid Bacteria Showing Antioxidative and Probiotic Activities from Kimchi and Infant Feces.

    PubMed

    Ji, Keunho; Jang, Na Young; Kim, Young Tae

    2015-09-01

    The purpose of this study was to investigate lactic acid bacteria with antioxidative and probiotic activities isolated from Korean healthy infant feces and kimchi. Isolates A1, A2, S1, S2, and S3 were assigned to Lactobacillus sp. and isolates A3, A4, E1, E2, E3, and E4 were assigned to Leuconostoc sp. on the basis of their physiological properties and 16S ribosomal DNA sequence analysis. Most strains were confirmed as safe bioresources through nonhemolytic activities and non-production of harmful enzymes such as β-glucosidase, β- glucuronidase and tryptophanase. The 11 isolates showed different resistance to acid and bile acids. In addition, they exhibited antibacterial activity against foodborne bacteria, especially Bacillus cereus, Listeria monocytogenes, and Escherichia coli. Furthermore, all strains showed significantly high levels of hydrophobicity. The antioxidant effects of culture filtrates of the 11 strains included 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging capacity, 2.2'- azino-bis (2-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation scavenging activity, and superoxide dismutase activity. The results revealed that most of the culture filtrates have effective scavenging activity for DPPH and ABTS radicals. All strains appeared to have effective superoxide dismutase activity. In conclusion, the isolated strains A1, A3, S1, and S3 have significant probiotic activities applicable to the development of functional foods and health-related products. These strains might also contribute to preventing and controlling several diseases associated with oxidative stress, when used as probiotics.

  14. Immunoregulatory Effects Triggered by Lactic Acid Bacteria Exopolysaccharides: New Insights into Molecular Interactions with Host Cells.

    PubMed

    Laiño, Jonathan; Villena, Julio; Kanmani, Paulraj; Kitazawa, Haruki

    2016-08-15

    Researchers have demonstrated that lactic acid bacteria (LAB) with immunomodulatory capabilities (immunobiotics) exert their beneficial effects through several molecules, including cell wall, peptidoglycan, and exopolysaccharides (EPS), that are able to interact with specific host cell receptors. EPS from LAB show a wide heterogeneity in its composition, meaning that biological properties depend on the strain and. therefore, only a part of the mechanism of action has been elucidated for these molecules. In this review, we summarize the current knowledge of the health-promoting actions of EPS from LAB with special focus on their immunoregulatory actions. In addition, we describe our studies using porcine intestinal epithelial cells (PIE cells) as a model to evaluate the molecular interactions of EPS from two immunobiotic LAB strains and the host cells. Our studies showed that EPS from immunobiotic LAB have anti-inflammatory capacities in PIE cells since they are able to reduce the production of inflammatory cytokines in cells challenged with the Toll-like receptor (TLR)-4-agonist lipopolysaccharide. The effects of EPS were dependent on TLR2, TLR4, and negative regulators of TLR signaling. We also reported that the radioprotective 105 (RP105)/MD1 complex, a member of the TLR family, is partially involved in the immunoregulatory effects of the EPS from LAB. Our work described, for the first time, that LAB and their EPS reduce inflammation in intestinal epithelial cells in a RP105/MD1-dependent manner. A continuing challenge for the future is to reveal more effector-receptor relationships in immunobiotic-host interactions that contribute to the beneficial effects of these bacteria on mucosal immune homeostasis. A detailed molecular understanding should lead to a more rational use of immunobiotics in general, and their EPS in particular, as efficient prevention and therapies for specific immune-related disorders in humans and animals.

  15. Antimicrobial activity of bacteriocin-producing lactic acid bacteria isolated from cheeses and yogurts.

    PubMed

    Yang, En; Fan, Lihua; Jiang, Yueming; Doucette, Craig; Fillmore, Sherry

    2012-09-10

    The biopreservation of foods using bacteriocinogenic lactic acid bacteria (LAB) isolated directly from foods is an innovative approach. The objectives of this study were to isolate and identify bacteriocinogenic LAB from various cheeses and yogurts and evaluate their antimicrobial effects on selected spoilage and pathogenic microorganisms in vitro as well as on a food commodity.LAB were isolated using MRS and M17 media. The agar diffusion bioassay was used to screen for bacteriocin or bacteriocin-like substances (BLS) producing LAB using Lactobacillus sakei and Listeria innocua as indicator organisms. Out of 138 LAB isolates, 28 were found to inhibit these bacteria and were identified as strains of Enterococcus faecium, Streptococcus thermophilus, Lactobacillus casei and Lactobacillus sakei subsp. sakei using 16S rRNA gene sequencing. Eight isolates were tested for antimicrobial activity at 5°C and 20°C against L. innocua, Escherichia coli, Bacillus cereus, Pseudomonas fluorescens, Erwinia carotovora, and Leuconostoc mesenteroides subsp. mesenteroides using the agar diffusion bioassay, and also against Penicillium expansum, Botrytis cinerea and Monilinia frucitcola using the microdilution plate method. The effect of selected LAB strains on L. innocua inoculated onto fresh-cut onions was also investigated.Twenty percent of our isolates produced BLS inhibiting the growth of L. innocua and/or Lact. sakei. Organic acids and/or H2O2 produced by LAB and not the BLS had strong antimicrobial effects on all microorganisms tested with the exception of E. coli. Ent. faecium, Strep. thermophilus and Lact. casei effectively inhibited the growth of natural microflora and L. innocua inoculated onto fresh-cut onions. Bacteriocinogenic LAB present in cheeses and yogurts may have potential to be used as biopreservatives in foods.

  16. Antimicrobial activity of bacteriocin-producing lactic acid bacteria isolated from cheeses and yogurts

    PubMed Central

    2012-01-01

    The biopreservation of foods using bacteriocinogenic lactic acid bacteria (LAB) isolated directly from foods is an innovative approach. The objectives of this study were to isolate and identify bacteriocinogenic LAB from various cheeses and yogurts and evaluate their antimicrobial effects on selected spoilage and pathogenic microorganisms in vitro as well as on a food commodity. LAB were isolated using MRS and M17 media. The agar diffusion bioassay was used to screen for bacteriocin or bacteriocin-like substances (BLS) producing LAB using Lactobacillus sakei and Listeria innocua as indicator organisms. Out of 138 LAB isolates, 28 were found to inhibit these bacteria and were identified as strains of Enterococcus faecium, Streptococcus thermophilus, Lactobacillus casei and Lactobacillus sakei subsp. sakei using 16S rRNA gene sequencing. Eight isolates were tested for antimicrobial activity at 5°C and 20°C against L. innocua, Escherichia coli, Bacillus cereus, Pseudomonas fluorescens, Erwinia carotovora, and Leuconostoc mesenteroides subsp. mesenteroides using the agar diffusion bioassay, and also against Penicillium expansum, Botrytis cinerea and Monilinia frucitcola using the microdilution plate method. The effect of selected LAB strains on L. innocua inoculated onto fresh-cut onions was also investigated. Twenty percent of our isolates produced BLS inhibiting the growth of L. innocua and/or Lact. sakei. Organic acids and/or H2O2 produced by LAB and not the BLS had strong antimicrobial effects on all microorganisms tested with the exception of E. coli. Ent. faecium, Strep. thermophilus and Lact. casei effectively inhibited the growth of natural microflora and L. innocua inoculated onto fresh-cut onions. Bacteriocinogenic LAB present in cheeses and yogurts may have potential to be used as biopreservatives in foods. PMID:22963659

  17. Immunoregulatory Effects Triggered by Lactic Acid Bacteria Exopolysaccharides: New Insights into Molecular Interactions with Host Cells

    PubMed Central

    Laiño, Jonathan; Villena, Julio; Kanmani, Paulraj; Kitazawa, Haruki

    2016-01-01

    Researchers have demonstrated that lactic acid bacteria (LAB) with immunomodulatory capabilities (immunobiotics) exert their beneficial effects through several molecules, including cell wall, peptidoglycan, and exopolysaccharides (EPS), that are able to interact with specific host cell receptors. EPS from LAB show a wide heterogeneity in its composition, meaning that biological properties depend on the strain and. therefore, only a part of the mechanism of action has been elucidated for these molecules. In this review, we summarize the current knowledge of the health-promoting actions of EPS from LAB with special focus on their immunoregulatory actions. In addition, we describe our studies using porcine intestinal epithelial cells (PIE cells) as a model to evaluate the molecular interactions of EPS from two immunobiotic LAB strains and the host cells. Our studies showed that EPS from immunobiotic LAB have anti-inflammatory capacities in PIE cells since they are able to reduce the production of inflammatory cytokines in cells challenged with the Toll-like receptor (TLR)-4-agonist lipopolysaccharide. The effects of EPS were dependent on TLR2, TLR4, and negative regulators of TLR signaling. We also reported that the radioprotective 105 (RP105)/MD1 complex, a member of the TLR family, is partially involved in the immunoregulatory effects of the EPS from LAB. Our work described, for the first time, that LAB and their EPS reduce inflammation in intestinal epithelial cells in a RP105/MD1-dependent manner. A continuing challenge for the future is to reveal more effector-receptor relationships in immunobiotic-host interactions that contribute to the beneficial effects of these bacteria on mucosal immune homeostasis. A detailed molecular understanding should lead to a more rational use of immunobiotics in general, and their EPS in particular, as efficient prevention and therapies for specific immune-related disorders in humans and animals. PMID:27681921

  18. Structure-Function Relationships of Glucansucrase and Fructansucrase Enzymes from Lactic Acid Bacteria

    PubMed Central

    van Hijum, Sacha A. F. T.; Kralj, Slavko; Ozimek, Lukasz K.; Dijkhuizen, Lubbert; van Geel-Schutten, Ineke G. H.

    2006-01-01

    Lactic acid bacteria (LAB) employ sucrase-type enzymes to convert sucrose into homopolysaccharides consisting of either glucosyl units (glucans) or fructosyl units (fructans). The enzymes involved are labeled glucansucrases (GS) and fructansucrases (FS), respectively. The available molecular, biochemical, and structural information on sucrase genes and enzymes from various LAB and their fructan and α-glucan products is reviewed. The GS and FS enzymes are both glycoside hydrolase enzymes that act on the same substrate (sucrose) and catalyze (retaining) transglycosylation reactions that result in polysaccharide formation, but they possess completely different protein structures. GS enzymes (family GH70) are large multidomain proteins that occur exclusively in LAB. Their catalytic domain displays clear secondary-structure similarity with α-amylase enzymes (family GH13), with a predicted permuted (β/α)8 barrel structure for which detailed structural and mechanistic information is available. Emphasis now is on identification of residues and regions important for GS enzyme activity and product specificity (synthesis of α-glucans differing in glycosidic linkage type, degree and type of branching, glucan molecular mass, and solubility). FS enzymes (family GH68) occur in both gram-negative and gram-positive bacteria and synthesize β-fructan polymers with either β-(2→6) (inulin) or β-(2→1) (levan) glycosidic bonds. Recently, the first high-resolution three-dimensional structures have become available for FS (levansucrase) proteins, revealing a rare five-bladed β-propeller structure with a deep, negatively charged central pocket. Although these structures have provided detailed mechanistic insights, the structural features in FS enzymes dictating the synthesis of either β-(2→6) or β-(2→1) linkages, degree and type of branching, and fructan molecular mass remain to be identified. PMID:16524921

  19. Assessment of the in vitro bioactive properties of lactic acid bacteria isolated from native ecological niches of Ecuador.

    PubMed

    Benavides, Ana B; Ulcuango, Mario; Yépez, Lucía; Tenea, Gabriela N

    Lactic acid bacteria are known for their biotechnological potential. In various regions of Ecuador numerous indigenous biological resources are largely undocumented. In this study, we evaluated the potential probiotic characteristics and antagonistic in vitro properties of some lactic acid bacteria from native niches of the subtropical rain forests of Ecuador. These isolates were identified according to their morphological properties, standard API50CH fermentation profile and RAPD-DNA polymorphism pattern. The selected isolates were further evaluated for their probiotic potential. The isolates grew at 15°C and 45°C, survived at a pH ranging from 2.5 to 4.5 in the presence of 0.3% bile (>90%) and grew under sodium chloride conditions. All selected isolates were sensitive to ampicillin, amoxicillin and cefuroxime and some showed resistance to gentamicin, kanamycin and tetracycline. Moreover, the agar well diffusion assay showed that the supernatant of each strain at pH 3.0 and pH 4.0, but not at pH 7.0 exhibited increased antimicrobial activity (inhibition zone >15mm) against two foodborne pathogens, Escherichia coli and Salmonella spp. To our knowledge, this is the first report describing the antagonistic activity against two foodborne pathogens and the probiotic in vitro potential of lactic acid bacteria isolated from native biota of Ecuador.

  20. Development and quality of a Brazilian semi-hard goat cheese (coalho) with added probiotic lactic acid bacteria.

    PubMed

    Garcia, Estefânia Fernandes; de Oliveira, Maria Elieidy Gomes; Queiroga, Rita de Cássia Ramos Do Egypto; Machado, Tamires Alcântara Dourado; de Souza, Evandro Leite

    2012-12-01

    The effects of the addition of different strains of lactic acid bacteria on different quality parameters of a Brazilian goat semi-hard cheese (coalho) were assessed during 7 days of storage (10°C) as follows: Control, Lactobacillus lactis subsp. lactis and L. lactis subsp. cremoris (standard); C2, L. acidophilus; C3, L. paracasei; C4, Bifidobacterium lactis; and C5, L. acidophilus, L. paracasei and B. lactis. There were no differences for the proteolysis index and depth of proteolysis among the assessed cheeses. The cheeses presented increase in hardness, gumminess and chewiness during the storage. Regarding the ability to melt, all evaluated cheeses showed a reduction in diameter. Cheeses presented high luminosity with predominance of the yellow component; and number of lactic bacteria greater than 10⁶-10⁷ cfu/g during the 7 days of storage. C5 had better sensory scores in the acceptance test, purchase intention and preference ranking test. Coalho goat cheese could be a potential carrier of probiotic lactic acid bacteria.

  1. Use of Gas-Liquid Chromatography to Determine the End Products of Growth of Lactic Acid Bacteria

    PubMed Central

    Thornhill, Patrick J.; Cogan, Timothy M.

    1984-01-01

    A simple gas-liquid chromatographic procedure for analyzing ethanol, acetic acid, acetoin, and racemic and meso-2,3-butylene glycol in broth media is described. Overnight broth cultures were filtered or centrifuged, and the filtrate or supernatant was treated with formic acid to aid separation of volatile fatty acids. Samples were then directly analyzed by gas-liquid chromatography on a 20% Tween 80-Chromosorb W-AW column and propionic acid as an internal standard. A complete analysis took ca. 8 min. The method can be used to distinguish homofermentative from heterofermentative lactic acid bacteria based on the level of ethanol produced and citrate-utilizing from non-citrate-utilizing lactic acid bacteria based on the levels of acetic acid produced. The method also has potential in distinguishing other bacterial fermentations. Of the 13 species of lactic acid bacteria tested, Streptococcus lactis subsp. diacetylactis was the major producer of 2,3-butylene glycol (total range, 0.3 to 3.5 mM), and, except for strain DRC1, both the racemic and meso isomers were produced in approximately equal amounts. PMID:16346562

  2. Culturing aerobic and anaerobic bacteria and mammalian cells with a microfluidic differential oxygenator.

    PubMed

    Lam, Raymond H W; Kim, Min-Cheol; Thorsen, Todd

    2009-07-15

    In this manuscript, we report on the culture of anaerobic and aerobic species within a disposable multilayer polydimethylsiloxane (PDMS) microfluidic device with an integrated differential oxygenator. A gas-filled microchannel network functioning as an oxygen-nitrogen mixer generates differential oxygen concentration. By controlling the relative flow rate of the oxygen and nitrogen input gases, the dissolved oxygen (DO) concentration in proximal microchannels filled with culture media are precisely regulated by molecular diffusion. Sensors consisting of an oxygen-sensitive dye embedded in the fluid channels permit dynamic fluorescence-based monitoring of the DO concentration using low-cost light-emitting diodes. To demonstrate the general utility of the platform for both aerobic and anaerobic culture, three bacteria with differential oxygen requirements (E. coli, A. viscosus, and F. nucleatum), as well as a model mammalian cell line (murine embryonic fibroblast cells (3T3)), were cultured. Growth characteristics of the selected species were analyzed as a function of eight discrete DO concentrations, ranging from 0 ppm (anaerobic) to 42 ppm (fully saturated).

  3. Analyses of spatial distributions of sulfate-reducing bacteria and their activity in aerobic wastewater biofilms

    SciTech Connect

    Okabe, Satoshi; Itoh, Tsukasa; Satoh, Hisashi; Watanabe, Yoshimasa

    1999-11-01

    The vertical distribution of sulfate-reducing bacteria (SRB) in aerobic wastewater biofilms grown on rotating disk reactors was investigated by fluorescent in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes. To correlate the vertical distribution of SRB populations with their activity, the microprofiles of O{sub 2}, H{sub 2}S, NO{sub 2}{minus}, NH{sub 2}{sup +}, and pH were measured with microelectrodes. In addition, a cross-evaluation of the FISH and microelectrode analyses was performed by comparing them with culture-based approaches and biogeochemical measurements. In situ hybridization revealed that a relatively high abundance of the probe SRB385-stained cells were evenly distributed throughout the biofilm, even in the toxic surface. The probe SRB660-stained Desulfobulbus spp. were found to be numerically important members of SRB populations. The result of microelectrode measurements showed that a high sulfate-reducing activity was found in a narrow anaerobic zone located about 150 to 300 {micro}m below the biofilm surface and above which an intensive sulfide oxidation zone was found. The biogeochemical measurements showed that elemental sulfur (S{degree}) was an important intermediate of the sulfide reoxidation in such thin wastewater biofilms, which accounted for about 75% of the total S pool in the biofilm. The contribution of an internal Fe-sulfur cycle to the overall sulfur cycle in aerobic wastewater biofilms was insignificant (less than 1%) due to the relatively high sulfate reduction rate.

  4. Culturable aerobic and facultative bacteria from the gut of the polyphagic dung beetle Thorectes lusitanicus.

    PubMed

    Hernández, Noemi; Escudero, José A; San Millán, Álvaro; González-Zorn, Bruno; Lobo, Jorge M; Verdú, José R; Suárez, Mónica

    2015-04-01

    Unlike other dung beetles, the Iberian geotrupid, Thorectes lusitanicus, exhibits polyphagous behavior; for example, it is able to eat acorns, fungi, fruits, and carrion in addition to the dung of different mammals. This adaptation to digest a wider diet has physiological and developmental advantages and requires key changes in the composition and diversity of the beetle's gut microbiota. In this study, we isolated aerobic, facultative anaerobic, and aerotolerant microbiota amenable to grow in culture from the gut contents of T. lusitanicus and resolved isolate identity to the species level by sequencing 16S rRNA gene fragments. Using BLAST similarity searches and maximum likelihood phylogenetic analyses, we were able to reveal that the analyzed fraction (culturable, aerobic, facultative anaerobic, and aerotolerant) of beetle gut microbiota is dominated by the phyla Proteobacteria, Firmicutes, and Actinobacteria. Among Proteobacteria, members of the order Enterobacteriales (Gammaproteobacteria) were the most abundant. The main functions associated with the bacteria found in the gut of T. lusitanicus would likely include nitrogen fixation, denitrification, detoxification, and diverse defensive roles against pathogens.

  5. Diversity and phylogeny of the ectoine biosynthesis genes in aerobic, moderately halophilic methylotrophic bacteria.

    PubMed

    Reshetnikov, Alexander S; Khmelenina, Valentina N; Mustakhimov, Ildar I; Kalyuzhnaya, Marina; Lidstrom, Mary; Trotsenko, Yuri A

    2011-11-01

    The genes of ectoine biosynthesis pathway were identified in six species of aerobic, slightly halophilic bacteria utilizing methane, methanol or methylamine. Two types of ectoine gene cluster organization were revealed in the methylotrophs. The gene cluster ectABC coding for diaminobutyric acid (DABA) acetyltransferase (EctA), DABA aminotransferase (EctB) and ectoine synthase (EctC) was found in methanotrophs Methylobacter marinus 7C and Methylomicrobium kenyense AMO1(T). In methanotroph Methylomicrobium alcaliphilum ML1, methanol-utilizers Methylophaga thalassica 33146(T) , Methylophaga alcalica M8 and methylamine-utilizer Methylarcula marina h1(T), the genes forming the ectABC-ask operon are preceded by ectR, encoding a putative transcriptional regulatory protein EctR. Phylogenetic relationships of the Ect proteins do not correlate with phylogenetic affiliation of the strains, thus implying that the ability of methylotrophs to produce ectoine is most likely the result of a horizontal transfer event.

  6. Isolation and identification of microorganisms including lactic acid bacteria and their use in microbial deacidification of wines from domestic vineyards.

    PubMed

    Drozdz, Iwona; Makarewicz, Malgorzata; Tuszyński, Tadeusz

    2013-01-01

    The aim of this study was to identify various bacteria isolated from grapes and their wines. Additionally we investigated the capacity of lactic acid bacteria for microbiological deacidification of wines produced in Poland. We have identified Oenococcus oeni, Lactobacillus acidophilus and Lactobacillus delbrueckii. During the microbial deacidification process, we observed decreases of total acidity and increases of volatile acidity, with statistically significant changes noted for O. oeni in Marechal Foch and Seyval Blanc, and for Lb. acidophilus in Frontenac. On the other hand, a statistically significant increase in pH was observed in Marechal Foch and Seyval Blanc following deacidification by O. oeni.

  7. [Use of real-time PCR for quantitative assessment of lactic acid bacteria and bifidobacteria in dairy products].

    PubMed

    Zelenaia, L B; Kovalenko, N K; Oblap, R V; Hovak, N B; Golubets, R A

    2012-01-01

    Composition of lactic acid bacteria and bifidobacteria in raw milk and home-made milk products has been analyzed using real-time PCR (quantitative PCR) with genus-specific primers to Enterococcus, Lactobacillus and Bifidobacteria. Bacteria belonging to these genera have been revealed in all samples analyzed (milk, sour cream, cottage cheese). It has been shown that the representatives of Enterococcus and Lactobacillus genera dominated in the samples analyzed (10(3)-10(7) genome equivalent/ml (mg)). The largest number of these microorganisms (10(7) genome equivalent/mg) has been detected in cottage cheese.

  8. Industrial application of selected lactic acid bacteria isolated from local semolinas for typical sourdough bread production.

    PubMed

    Corona, Onofrio; Alfonzo, Antonio; Ventimiglia, Giusi; Nasca, Anna; Francesca, Nicola; Martorana, Alessandra; Moschetti, Giancarlo; Settanni, Luca

    2016-10-01

    Four obligate heterofermentative lactic acid bacteria (LAB) strains (Weissella cibaria PON10030 and PON10032 and Leuconostoc citreum PON 10079 and PON10080) were tested as single strain starters, mono-species dual strain starters, and multiple strain starter for the preparation and propagation of sourdoughs for the production of a typical bread at industrial level. The kinetics of pH and TTA during the daily sourdough refreshments indicated a correct acidification process for all trials. The concentration of lactic and acetic acid increased consistently during fermentation. The resulting molar ratios between these two organic acids in the experimental trials were lower than those observed in the control trial. The microbiological investigation showed levels of approximately 10(9) CFU/mL in almost all sourdoughs and the comparison of the genetic polymorphisms of the dominating LAB with those of the pure cultures evidenced the persistence of the added strains over time. The resulting breads were evaluated for several quality parameters. The breads with the greatest height were obtained with the quadruple combination of leuconostocs and weissellas. The highest softness was registered for the breads obtained from fermentations performed by W. cibaria PON10032 alone and in combination. The different inocula influenced also the color, the void fraction, the cell density and the mean cell area of the breads. Different levels of acids, alcohols, aldehydes, esters, hydrocarbons, ketones, terpenes, furans and phenol were emitted by the breads. The sensory tests indicated the breads from the sourdoughs fermented with the seven LAB inocula as sweeter and less acidic than control breads and the breads from the trials with the highest complexity of LAB inoculums were those more appreciated by tasters. A multivariate approach found strong differences among the trials. In particular, control breads and the breads obtained with different starter LAB were quite distant and a more

  9. Comparison between rinse and crush-and-rub sampling for aerobic bacteria recovery from broiler hatching eggs after sanitization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study compared surface and deep eggshell aerobic bacteria recovered by rinse and crush-and-rub sampling methods for commercial hatching eggs after treatment with sanitizers. Eggs were arranged into 5 treatments consisting of No-treatment, Water, and three sanitizers. Sanitizers were Hydrogen ...

  10. Comparison between Rinse and Crush-and-Rub Sampling for Aerobic Bacteria Recovery from Hatching Eggs after Sanitization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study compared surface and deep eggshell aerobic bacteria recovered by rinse and crush-and-rub sampling methods for commercial hatching eggs after treatments with sanitizers. Eggs were arranged into 5 treatments consisting of three sanitizers, Water, and No-treatment. Sanitizers were Hydrogen...

  11. Growth of Aerobic Ripening Bacteria at the Cheese Surface Is Limited by the Availability of Iron

    PubMed Central

    Back, Alexandre; Irlinger, Françoise

    2012-01-01

    The microflora on the surface of smear-ripened cheeses is composed of various species of bacteria and yeasts that contribute to the production of the desired organoleptic properties. The objective of the present study was to show that iron availability is a limiting factor in the growth of typical aerobic ripening bacteria in cheese. For that purpose, we investigated the effect of iron or siderophore addition in model cheeses that were coinoculated with a yeast and a ripening bacterium. Both iron and the siderophore desferrioxamine B stimulated the growth of ripening bacteria belonging to the genera Arthrobacter, Corynebacterium, and Brevibacterium. The extent of stimulation was strain dependent, and generally, the effect of desferrioxamine B was greater than that of iron. Measurements of the expression of genes related to the metabolism of iron by Arthrobacter arilaitensis Re117 by real-time reverse transcription-PCR showed that these genes were transcribed during growth in cheese. The addition of desferrioxamine B increased the expression of two genes encoding iron-siderophore ABC transport binding proteins. The addition of iron decreased the expression of siderophore biosynthesis genes and of part of the genes encoding iron-siderophore ABC transport components. It was concluded that iron availability is a limiting factor in the growth of typical cheese surface bacteria. The selection of strains with efficient iron acquisition systems may be useful for the development of defined-strain surface cultures. Furthermore, the importance of iron metabolism in the microbial ecology of cheeses should be investigated since it may result in positive or negative microbial interactions. PMID:22367081

  12. Growth of aerobic ripening bacteria at the cheese surface is limited by the availability of iron.

    PubMed

    Monnet, Christophe; Back, Alexandre; Irlinger, Françoise

    2012-05-01

    The microflora on the surface of smear-ripened cheeses is composed of various species of bacteria and yeasts that contribute to the production of the desired organoleptic properties. The objective of the present study was to show that iron availability is a limiting factor in the growth of typical aerobic ripening bacteria in cheese. For that purpose, we investigated the effect of iron or siderophore addition in model cheeses that were coinoculated with a yeast and a ripening bacterium. Both iron and the siderophore desferrioxamine B stimulated the growth of ripening bacteria belonging to the genera Arthrobacter, Corynebacterium, and Brevibacterium. The extent of stimulation was strain dependent, and generally, the effect of desferrioxamine B was greater than that of iron. Measurements of the expression of genes related to the metabolism of iron by Arthrobacter arilaitensis Re117 by real-time reverse transcription-PCR showed that these genes were transcribed during growth in cheese. The addition of desferrioxamine B increased the expression of two genes encoding iron-siderophore ABC transport binding proteins. The addition of iron decreased the expression of siderophore biosynthesis genes and of part of the genes encoding iron-siderophore ABC transport components. It was concluded that iron availability is a limiting factor in the growth of typical cheese surface bacteria. The selection of strains with efficient iron acquisition systems may be useful for the development of defined-strain surface cultures. Furthermore, the importance of iron metabolism in the microbial ecology of cheeses should be investigated since it may result in positive or negative microbial interactions.

  13. Genotypic characterization and safety assessment of lactic acid bacteria from indigenous African fermented food products

    PubMed Central

    2012-01-01

    Background Indigenous fermented food products play an essential role in the diet of millions of Africans. Lactic acid bacteria (LAB) are among the predominant microbial species in African indigenous fermented food products and are used for different applications in the food and biotechnology industries. Numerous studies have described antimicrobial susceptibility profiles of LAB from different parts of the world. However, there is limited information on antimicrobial resistance profiles of LAB from Africa. The aim of this study was to characterize 33 LAB previously isolated from three different African indigenous fermented food products using (GTG)5-based rep-PCR, sequencing of the 16S rRNA gene and species-specific PCR techniques for differentiation of closely related species and further evaluate their antibiotic resistance profiles by the broth microdilution method and their haemolytic activity on sheep blood agar plates as indicators of safety traits among these bacteria. Results Using molecular biology based methods and selected phenotypic tests such as catalase reaction, CO2 production from glucose, colonies and cells morphology, the isolates were identified as Lactobacillus delbrueckii, Lactobacillus fermentum, Lactobacillus ghanensis, Lactobacillus plantarum, Lactobacillus salivarius, Leuconostoc pseudomesenteroides, Pediococcus acidilactici, Pediococcus pentosaceus and Weissella confusa. The bacteria were susceptible to ampicillin, chloramphenicol, clindamycin and erythromycin but resistant to vancomycin, kanamycin and streptomycin. Variable sensitivity profiles to tetracycline and gentamicin was observed among the isolates with Lb. plantarum, Lb. salivarius, W. confusa (except strain SK9-5) and Lb. fermentum strains being susceptible to tetracycline whereas Pediococcus strains and Lb. ghanensis strains were resistant. For gentamicin, Leuc. pseudomesenteroides, Lb. ghanensis and Ped. acidilactici strains were resistant to 64 mg/L whereas some W. confusa

  14. Exploitation of sweet cherry (Prunus avium L.) puree added of stem infusion through fermentation by selected autochthonous lactic acid bacteria.

    PubMed

    Di Cagno, Raffaella; Surico, Rosalinda Fortunata; Minervini, Giovanna; Rizzello, Carlo Giuseppe; Lovino, Raffaella; Servili, Maurizio; Taticchi, Agnese; Urbani, Sefania; Gobbetti, Marco

    2011-08-01

    Strains of Lactobacillus plantarum, Pediococcus acidilactici, Pediococcus pentosaceus and Leuconostoc mesenteroides subsp. mesenteroides were identified from 8 cultivars of sweet cherry by partial 16S rRNA gene sequence and subjected to typing by Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) analysis. Representative isolates from each species and each cultivar were screened based on the kinetics of growth on cherry puree added of (10%, v/v) stem infusion (CP-SI). A protocol for processing and storage of CP-SI, which included fermentation by selected autochthonous P. pentosaceus SWE5 and L. plantarum FP3 (started CP-SI) or spontaneous fermentation (unstarted CP-SI), was set up. Starters grew and remained viable at elevated cell numbers (ca. 9.0 log cfu g(-1)) during 60 days of storage at 4 °C. The number of presumptive lactic acid bacteria of the unstarted CP-SI did not exceed the value of ca. 3.0 log cfu g(-1). Consumption of carbohydrates (e.g., glucose and fructose) by starter lactic acid bacteria was limited as well as it was the lactic acid fermentation. Consumption of organic acids (e.g., malic acid) and free amino acids was evident, especially, throughout storage. Compared to CP-SI before processing, the concentrations of total phenolic compounds and anthocyanins did not vary in the started CP-SI. The concentration of anthocyanins slightly decreased in the unstarted CP-SI. The antioxidant activity, expressed as the scavenging activity toward DPPH radical, was found at highest level in the started CP-SI which approached that found in CP-SI before processing. During storage, viscosity and, especially, color indexes of started CP-SI were higher than those found in the unstarted CP-SI. Fermentation by autochthonous lactic acid bacteria seemed to also positively interfere with the sensory attributes of CP-SI.

  15. Study of Lactic Acid Bacteria Community From Raw Milk of Iranian One Humped Camel and Evaluation of Their Probiotic Properties

    PubMed Central

    Davati, Nafiseh; Tabatabaee Yazdi, Farideh; Zibaee, Saeed; Shahidi, Fakhri; Edalatian, Mohammad Reza

    2015-01-01

    Background: Camel milk is amongst valuable food sources in Iran. On the other hand, due to the presence of probiotic bacteria and bacteriocin producers in camel milk, probiotic bacteria can be isolated and identified from this food product. Objectives: The objectives of the present research were the isolation and molecular identification of lactic acid bacteria from camel milk and evaluation of their probiotic properties. Materials and Methods: A total of ten samples of camel milk were collected from the Golestan province of Iran under aseptic conditions. Bacteria were isolated by culturing the samples on selective medium. Isolates were identified by amplification of the 16S rDNA and Internal Transcribed Spacer (ITS) region between the 16S and 23S rRNA genes by Polymerase Chain Reaction (PCR) and were then screened and grouped by the Amplified Ribosomal DNA Restriction Analysis (ARDRA) method. To evaluate probiotic properties, representative isolates of different ARDRA profiles were analyzed. The antimicrobial activity of Lactic Acid Bacteria (LAB) against Pediococcus pentosaceus, Escherichia coli and Bacillus cereus was examined by the agar diffusion assay. Acid and bile tolerance of isolates were evaluated. Results: A total of 64 isolates were analyzed based on biochemical tests and morphological characteristics. The most frequently isolated LAB was Enterococci. Weissella, Leuconostoc, Lactobacilli and Pediococci were less frequently found. Based on restriction analysis of the ITS, the isolates were grouped into nine different ARDRA patterns that were identified by ribosomal DNA sequencing as P. pentosaceus, Enterococcus faecium strain Y-2, E. faecium strain JZ1-1, E. faecium strain E6, E. durans, E. lactis, Leuconostoc mesenteroides, Lactobacillus casei and Weissella cibaria. The results showed that antimicrobial activity of the tested isolates was remarkable and P. pentosaceus showed the most antibacterial activity. In addition, E. durans, E. lactis, L. casei

  16. An initial investigation into the ecology of culturable aerobic postmortem bacteria.

    PubMed

    Chun, Lauren P; Miguel, Marcus J; Junkins, Emily N; Forbes, Shari L; Carter, David O

    2015-12-01

    Postmortem microorganisms are increasingly recognized for their potential to serve as physical evidence. Yet, we still understand little about the ecology of postmortem microbes, particularly those associated with the skin and larval masses. We conducted an experiment to characterize microbiological and chemical properties of decomposing swine (Sus scrofa domesticus) carcasses on the island of Oahu, Hawaii, USA, during June 2013. Bacteria were collected from the head, limb, and larval mass during the initial 145h of decomposition. We also measured the pH, temperature, and oxidation-reduction potential of larval masses in situ. Bacteria were cultured aerobically on Standard Nutrient Agar at 22°C and identified using protein or genetic signals. Carcass decomposition followed a typical sigmoidal pattern and associated bacterial communities differed by sampling location and time since death, although all communities were dominated by phyla Actinobacteria, Firmicutes, and Proteobacteria. Larval masses were reducing environments (~-200mV) of neutral pH (6.5-7.5) and high temperature (35°C-40°C). We recommend that culturable postmortem and larval mass microbiology and chemistry be investigated in more detail, as it has potential to complement culture-independent studies and serve as a rapid estimate of PMI.

  17. Reducing time to identification of aerobic bacteria and fastidious micro-organisms in positive blood cultures.

    PubMed

    Intra, J; Sala, M R; Falbo, R; Cappellini, F; Brambilla, P

    2016-12-01

    Rapid and early identification of micro-organisms in blood has a key role in the diagnosis of a febrile patient, in particular, in guiding the clinician to define the correct antibiotic therapy. This study presents a simple and very fast method with high performances for identifying bacteria by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) after only 4 h of incubation. We used early bacterial growth on PolyViteX chocolate agar plates inoculated with five drops of blood-broth medium deposited in the same point and spread with a sterile loop, followed by a direct transfer procedure on MALDI-TOF MS target slides without additional modification. Ninety-nine percentage of aerobic bacteria were correctly identified from 600 monomicrobial-positive blood cultures. This procedure allowed obtaining the correct identification of fastidious pathogens, such as Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae that need complex nutritional and environmental requirements in order to grow. Compared to the traditional pathogen identification from blood cultures that takes over 24 h, the reliability of results, rapid performance and suitability of this protocol allowed a more rapid administration of optimal antimicrobial treatment in the patients.

  18. Acetic acid production from food wastes using yeast and acetic acid bacteria micro-aerobic fermentation.

    PubMed

    Li, Yang; He, Dongwei; Niu, Dongjie; Zhao, Youcai

    2015-05-01

    In this study, yeast and acetic acid bacteria strains were adopted to enhance the ethanol-type fermentation resulting to a volatile fatty acids yield of 30.22 g/L, and improve acetic acid production to 25.88 g/L, with food wastes as substrate. In contrast, only 12.81 g/L acetic acid can be obtained in the absence of strains. The parameters such as pH, oxidation reduction potential and volatile fatty acids were tested and the microbial diversity of different strains and activity of hydrolytic ferment were investigated to reveal the mechanism. The optimum pH and oxidation reduction potential for the acetic acid production were determined to be at 3.0-3.5 and -500 mV, respectively. Yeast can convert organic matters into ethanol, which is used by acetic acid bacteria to convert the organic wastes into acetic acid. The acetic acid thus obtained from food wastes micro-aerobic fermentation liquid could be extracted by distillation to get high-pure acetic acid.

  19. Molecular identification and physiological characterization of yeasts, lactic acid bacteria and acetic acid bacteria isolated from heap and box cocoa bean fermentations in West Africa.

    PubMed

    Visintin, Simonetta; Alessandria, Valentina; Valente, Antonio; Dolci, Paola; Cocolin, Luca

    2016-01-04

    Yeast, lactic acid bacteria (LAB) and acetic acid bacteria (AAB) populations, isolated from cocoa bean heap and box fermentations in West Africa, have been investigated. The fermentation dynamicswere determined by viable counts, and 106 yeasts, 105 LAB and 82 AAB isolateswere identified by means of rep-PCR grouping and sequencing of the rRNA genes. During the box fermentations, the most abundant species were Saccharomyces cerevisiae, Candida ethanolica, Lactobacillus fermentum, Lactobacillus plantarum, Acetobacter pasteurianus and Acetobacter syzygii, while S. cerevisiae, Schizosaccharomyces pombe, Hanseniaspora guilliermondii, Pichia manshurica, C. ethanolica, Hanseniaspora uvarum, Lb. fermentum, Lb. plantarum, A. pasteurianus and Acetobacter lovaniensis were identified in the heap fermentations. Furthermore, the most abundant species were molecularly characterized by analyzing the rep-PCR profiles. Strains grouped according to the type of fermentations and their progression during the transformation process were also highlighted. The yeast, LAB and AAB isolates were physiologically characterized to determine their ability to grow at different temperatures, as well as at different pH, and ethanol concentrations, tolerance to osmotic stress, and lactic acid and acetic acid inhibition. Temperatures of 45 °C, a pH of 2.5 to 3.5, 12% (v/v) ethanol and high concentrations of lactic and acetic acid have a significant influence on the growth of yeasts, LAB and AAB. Finally, the yeastswere screened for enzymatic activity, and the S. cerevisiae, H. guilliermondii, H. uvarumand C. ethanolica species were shown to possess several enzymes that may impact the quality of the final product.

  20. Lactic Acid Bacteria in Durum Wheat Flour Are Endophytic Components of the Plant during Its Entire Life Cycle.

    PubMed

    Minervini, Fabio; Celano, Giuseppe; Lattanzi, Anna; Tedone, Luigi; De Mastro, Giuseppe; Gobbetti, Marco; De Angelis, Maria

    2015-10-01

    This study aimed at assessing the dynamics of lactic acid bacteria and other Firmicutes associated with durum wheat organs and processed products. 16S rRNA gene-based high-throughput sequencing showed that Lactobacillus, Streptococcus, Enterococcus, and Lactococcus were the main epiphytic and endophytic genera among lactic acid bacteria. Bacillus, Exiguobacterium, Paenibacillus, and Staphylococcus completed the picture of the core genus microbiome. The relative abundance of each lactic acid bacterium genus was affected by cultivars, phenological stages, other Firmicutes genera, environmental temperature, and water activity (aw) of plant organs. Lactobacilli, showing the highest sensitivity to aw, markedly decreased during milk development (Odisseo) and physiological maturity (Saragolla). At these stages, Lactobacillus was mainly replaced by Streptococcus, Lactococcus, and Enterococcus. However, a key sourdough species, Lactobacillus plantarum, was associated with plant organs during the life cycle of Odisseo and Saragolla wheat. The composition of the sourdough microbiota and the overall quality of leavened baked goods are also determined throughout the phenological stages of wheat cultivation, with variations depending on environmental and agronomic factors.

  1. Lactic Acid Bacteria in Durum Wheat Flour Are Endophytic Components of the Plant during Its Entire Life Cycle

    PubMed Central

    Minervini, Fabio; Celano, Giuseppe; Lattanzi, Anna; Tedone, Luigi; De Mastro, Giuseppe; De Angelis, Maria

    2015-01-01

    This study aimed at assessing the dynamics of lactic acid bacteria and other Firmicutes associated with durum wheat organs and processed products. 16S rRNA gene-based high-throughput sequencing showed that Lactobacillus, Streptococcus, Enterococcus, and Lactococcus were the main epiphytic and endophytic genera among lactic acid bacteria. Bacillus, Exiguobacterium, Paenibacillus, and Staphylococcus completed the picture of the core genus microbiome. The relative abundance of each lactic acid bacterium genus was affected by cultivars, phenological stages, other Firmicutes genera, environmental temperature, and water activity (aw) of plant organs. Lactobacilli, showing the highest sensitivity to aw, markedly decreased during milk development (Odisseo) and physiological maturity (Saragolla). At these stages, Lactobacillus was mainly replaced by Streptococcus, Lactococcus, and Enterococcus. However, a key sourdough species, Lactobacillus plantarum, was associated with plant organs during the life cycle of Odisseo and Saragolla wheat. The composition of the sourdough microbiota and the overall quality of leavened baked goods are also determined throughout the phenological stages of wheat cultivation, with variations depending on environmental and agronomic factors. PMID:26187970

  2. Antimicrobial activity of neutralized extracellular culture filtrates of lactic acid bacteria isolated from a cultured Indian milk product ('dahi').

    PubMed

    Varadaraj, M C; Devi, N; Keshava, N; Manjrekar, S P

    1993-12-01

    Neutralized extracellular culture filtrate obtained from isolates of Lactobacillus acidophilus, Lactobacillus delbruecki ssp. bulgaricus, Lactobacillus salivarius and Lactococcus lactis ssp. lactis from 'dahi' showed weak to moderate inhibition of Staphylococcus aureus, Bacillus cereus, Escherichia coli, Bacillus brevis, Bacillus circulans, Bacillus coagulans, Bacillus laterosporus, Bacillus subtilis and Pseudomonas aeruginosa when tested by the diffusion agar well assay method. The effective minimum quantity of lactic culture filtrates required to obtain complete inhibition of an inoculum of 10(3) cfu/ml of the bacteria tested was between 20 and 26% (vol/vol), as determined by the agar incorporation method. Neutralized extracellular culture filtrate of these lactic cultures added at a level of 10% in sterile, 10% reconstituted non-fat dry milk was able to either suppress or retard growth of selected bacterial cultures when incubated at 37 degrees C for 24 h. This study indicated the antimicrobial activity of dahi and the potential of using neutralized extracellular culture filtrate of lactic acid bacteria in the biopreservation of foods.

  3. Genetic diversity, safety and technological characterization of lactic acid bacteria isolated from artisanal Pico cheese.

    PubMed

    Domingos-Lopes, M F P; Stanton, C; Ross, P R; Dapkevicius, M L E; Silva, C C G

    2017-05-01

    A total of 114 lactic acid bacteria were isolated at one and 21 days of ripening from a traditional raw cow's milk cheese without the addition of starter culture, produced by three artisanal cheese-makers in Azores Island (Pico, Portugal). Identification to species and strain level was accomplished by16S rRNA gene and PFGE analysis. Carbohydrate utilization profiles were obtained with the relevant API kits. Isolates were evaluated according to safety and technological criteria. The most frequently observed genus identified by 16S rRNA sequencing analysis was Enterococcus, whereas API system mostly identified Lactobacillus. The highest percentages of antibiotic resistance were to nalidixic acid (95%), and aminoglycosides (64-87%). All isolates were sensitive to several beta-lactam antibiotics and negative for histamine and DNase production. Gelatinase activity was detected in 49.1% of isolates, 43% were able to degrade casein and 93% were α-hemolytic. Most enterococci presented virulence genes, such as gelE, asaI, ace. Diacetyl production was found to be species dependent and one strain (Leu. citreum) produced exopolysaccharides. Selected strains were further studied for technological application and were found to be slow acid producers in milk and experimental cheeses, a desirable trait for adjunct cultures. Two strains were selected on the basis of technological and safety application as adjunct cultures in cheese production and presented the best cheese aroma and flavor in consumer preference tests. This is the first effort to characterize Pico cheese LAB isolates for potential application as adjunct cultures; the results suggest the potential of two strains to improve the quality of this traditional raw milk product.

  4. Codominance of Lactobacillus plantarum and obligate heterofermentative lactic acid bacteria during sourdough fermentation.

    PubMed

    Ventimiglia, Giusi; Alfonzo, Antonio; Galluzzo, Paola; Corona, Onofrio; Francesca, Nicola; Caracappa, Santo; Moschetti, Giancarlo; Settanni, Luca

    2015-10-01

    Fifteen sourdoughs produced in western Sicily (southern Italy) were analysed by classical methods for their chemico-physical characteristics and the levels of lactic acid bacteria (LAB). pH and total titratable acidity (TTA) were mostly in the range commonly reported for similar products produced in Italy, but the fermentation quotient (FQ) of the majority of samples was above 4.0, due to the low concentration of acetic acid estimated by high performance liquid chromatography (HPLC). Specific counts of LAB showed levels higher than 10(8) CFU g(-1) for many samples. The colonies representing various morphologies were isolated and, after the differentiation based on phenotypic characteristics, divided into 10 groups. The most numerous group was composed of facultative heterofermentative isolates, indicating a relevance of this bacterial group during fermentation. The genetic analysis by randomly amplified polymorphic DNA (RAPD)-PCR, 16S rRNA gene sequencing and species-specific PCRs identified 33 strains as Lactobacillus plantarum, Lactobacillus curvatus and Lactobacillus graminis. Due to the consistent presence of L. plantarum, it was concluded that this species codominates with obligate heterofermentative LAB in sourdough production in this geographical area. In order to evaluate the performances at the basis of their fitness, the 29 L. plantarum strains were investigated for several technological traits. Twelve cultures showed good acidifying abilities in vitro and L. plantarum PON100148 produced the highest concentrations of organic acids. Eleven strains were positive for extracellular protease activity. Bacteriocin-like inhibitory substances (BLIS) production and antifungal activity was scored positive for several strains, included L. plantarum PON100148 which was selected as starter for experimental sourdough production. The characteristics of the sourdoughs and the resulting breads indicated that the best productions were obtained in presence of L

  5. Antifungal Activity of Lactic Acid Bacteria Strains Isolated from Natural Honey against Pathogenic Candida Species

    PubMed Central

    Bulgasem, Bulgasem Y.; Lani, Mohd Nizam; Wan Yusoff, Wan Mohtar; Fnaish, Sumaya G.

    2016-01-01

    The role of lactic acid bacteria (LAB) in honey as antifungal activity has received little attention and their mechanism of inhibitory of fungi is not fully understood. In this study, LAB were isolated from honey samples from Malaysia, Libya, Saudi Arabia, and Yemen. Twenty-five isolates were confirmed LAB by catalase test and Gram staining, and were screened for antifungal activity. Four LAB showed inhibitory activity against Candida spp. using the dual agar overlay method. And they were identified as Lactobacillus plantarum HS isolated from Al-Seder honey, Lactobacillus curvatus HH isolated from Al-Hanon honey, Pediococcus acidilactici HC isolated from Tualang honey and Pediococcus pentosaceus HM isolated from Al-Maray honey by the 16S rDNA sequence. The growth of Candida glabrata ATCC 2001 was strongly inhibited (>15.0 mm) and (10~15 mm) by the isolates of L. curvatus HH and P. pentosaceus HM, respectively. The antifungal activity of the crude supernatant (cell free supernatant, CFS) was evaluated using well diffusion method. The CFS showed high antifungal activity against Candida spp. especially The CFS of L. curvatus HH was significantly (p < 0.05) inhibited growth of C. glabrata ATCC 2001, C. parapsilosis ATCC 2201, and C. tropicalis ATCC 750 with inhibitory zone 22.0, 15.6, and 14.7 mm, respectively. While CFS of P. pentosaceus HM was significantly (p < 0.05) effective against C. krusei, C. glabrata, and C. albicans with inhibition zone 17.2, 16.0, and 13.3 mm, respectively. The results indicated that LAB isolated from honey produced compounds which can be used to inhibit the growth of the pathogenic Candida species. PMID:28154488

  6. Efficacy of Lactic Acid Bacteria (LAB) supplement in management of constipation among nursing home residents

    PubMed Central

    2010-01-01

    Background Constipation is a significant problem in the elderly, specifically nursing home and/or extended-care facility residents are reported to suffer from constipation. Lactic acid bacteria (LAB) are beneficial probiotic organisms that contribute to improved nutrition, microbial balance, and immuno-enhancement of the intestinal tract, as well as diarrhea and constipation effect. The objective of this study was to investigate the efficacy of this LAB supplement in the management of nursing home residents. Methods Nineteen subjects (8M, 11F; mean age 77.1 ± 10.1) suffering with chronic constipation were assigned to receive LAB (3.0 × 1011 CFU/g) twice (to be taken 30 minutes after breakfast and dinner) a day for 2 weeks in November 2008. Subjects draw up a questionnaire on defecation habits (frequency of defecation, amount and state of stool), and we collected fecal samples from the subjects both before entering and after ending the trial, to investigate LAB levels and inhibition of harmful enzyme activities. Results were tested with SAS and Student's t-test. Results Analysis of questionnaire showed that there was an increase in the frequency of defecation and amount of stool excreted in defecation habit after LAB treatment, but there were no significant changes. And it also affects the intestinal environment, through significantly increase (p < 0.05) fecal LAB levels. In addition, tryptophanase and urease among harmful enzyme activities of intestinal microflora were significantly decreased (p < 0.05) after LAB treatment. Conclusion LAB, when added to the standard treatment regimen for nursing home residents with chronic constipation, increased defecation habit such as frequency of defecation, amount and state of stool. So, it may be used as functional probiotics to improve human health by helping to prevent constipation. PMID:20137076

  7. Identification and Antimicrobial Activity Detection of Lactic Acid Bacteria Isolated from Corn Stover Silage

    PubMed Central

    Li, Dongxia; Ni, Kuikui; Pang, Huili; Wang, Yanping; Cai, Yimin; Jin, Qingsheng

    2015-01-01

    A total of 59 lactic acid bacteria (LAB) strains were isolated from corn stover silage. According to phenotypic and chemotaxonomic characteristics, 16S ribosomal DNA (rDNA) sequences and recA gene polymerase chain reaction amplification, these LAB isolates were identified as five species: Lactobacillus (L.) plantarum subsp. plantarum, Pediococcus pentosaceus, Enterococcus mundtii, Weissella cibaria and Leuconostoc pseudomesenteroides, respectively. Those strains were also screened for antimicrobial activity using a dual-culture agar plate assay. Based on excluding the effects of organic acids and hydrogen peroxide, two L. plantarum subsp. plantarum strains ZZU 203 and 204, which strongly inhibited Salmonella enterica ATCC 43971T, Micrococcus luteus ATCC 4698T and Escherichia coli ATCC 11775T were selected for further research on sensitivity of the antimicrobial substance to heat, pH and protease. Cell-free culture supernatants of the two strains exhibited strong heat stability (60 min at 100°C), but the antimicrobial activity was eliminated after treatment at 121°C for 15 min. The antimicrobial substance remained active under acidic condition (pH 2.0 to 6.0), but became inactive under neutral and alkaline condition (pH 7.0 to 9.0). In addition, the antimicrobial activities of these two strains decreased remarkably after digestion by protease K. These results preliminarily suggest that the desirable antimicrobial activity of strains ZZU 203 and 204 is the result of the production of a bacteriocin-like substance, and these two strains with antimicrobial activity could be used as silage additives to inhibit proliferation of unwanted microorganism during ensiling and preserve nutrients of silage. The nature of the antimicrobial substances is being investigated in our laboratory. PMID:25924957

  8. Bacillus spp. produce antibacterial activities against lactic acid bacteria that contaminate fuel ethanol plants.

    PubMed

    Manitchotpisit, Pennapa; Bischoff, Kenneth M; Price, Neil P J; Leathers, Timothy D

    2013-05-01

    Lactic acid bacteria (LAB) frequently contaminate commercial fuel ethanol fermentations, reducing yields and decreasing profitability of biofuel production. Microorganisms from environmental sources in different geographic regions of Thailand were tested for antibacterial activity against LAB. Four bacterial strains, designated as ALT3A, ALT3B, ALT17, and MR1, produced inhibitory effects on growth of LAB. Sequencing of rRNA identified these strains as species of Bacillus subtilis (ALT3A and ALT3B) and B. cereus (ALT17 and MR1). Cell mass from colonies and agar samples from inhibition zones were analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The spectra of ALT3A and ALT3B showed a strong signal at m/z 1,060, similar in mass to the surfactin family of antimicrobial lipopeptides. ALT3A and ALT3B were analyzed by zymogram analysis using SDS-PAGE gels placed on agar plates inoculated with LAB. Cell lysates possessed an inhibitory protein of less than 10 kDa, consistent with the production of an antibacterial lipopeptide. Mass spectra of ALT17 and MR1 had notable signals at m/z 908 and 930 in the whole cell extracts and at m/z 687 in agar, but these masses do not correlate with those of previously reported antibacterial lipopeptides, and no antibacterial activity was detected by zymogram. The antibacterial activities produced by these strains may have application in the fuel ethanol industry as an alternative to antibiotics for prevention and control of bacterial contamination.

  9. Lactic acid bacteria contribution to gut microbiota complexity: lights and shadows

    PubMed Central

    Pessione, Enrica

    2012-01-01

    Lactic Acid Bacteria (LAB) are ancient organisms that cannot biosynthesize functional cytochromes, and cannot get ATP from respiration. Besides sugar fermentation, they evolved electrogenic decarboxylations and ATP-forming deiminations. The right balance between sugar fermentation and decarboxylation/deimination ensures buffered environments thus enabling LAB to survive in human gastric trait and colonize gut. A complex molecular cross-talk between LAB and host exists. LAB moonlight proteins are made in response to gut stimuli and promote bacterial adhesion to mucosa and stimulate immune cells. Similarly, when LAB are present, human enterocytes activate specific gene expression of specific genes only. Furthermore, LAB antagonistic relationships with other microorganisms constitute the basis for their anti-infective role. Histamine and tyramine are LAB bioactive catabolites that act on the CNS, causing hypertension and allergies. Nevertheless, some LAB biosynthesize both gamma-amino-butyrate (GABA), that has relaxing effect on gut smooth muscles, and beta-phenylethylamine, that controls satiety and mood. Since LAB have reduced amino acid biosynthetic abilities, they developed a sophisticated proteolytic system, that is also involved in antihypertensive and opiod peptide generation from milk proteins. Short-chain fatty acids are glycolytic and phosphoketolase end-products, regulating epithelial cell proliferation and differentiation. Nevertheless, they constitute a supplementary energy source for the host, causing weight gain. Human metabolism can also be affected by anabolic LAB products such as conjugated linoleic acids (CLA). Some CLA isomers reduce cancer cell viability and ameliorate insulin resistance, while others lower the HDL/LDL ratio and modify eicosanoid production, with detrimental health effects. A further appreciated LAB feature is the ability to fix selenium into seleno-cysteine. Thus, opening interesting perspectives for their utilization as

  10. Lactic Acid Bacteria Isolated from Bovine Mammary Microbiota: Potential Allies against Bovine Mastitis

    PubMed Central

    Saraoui, Taous; Rault, Lucie; Germon, Pierre; Gonzalez-Moreno, Candelaria; Nader-Macias, Fatima M. E.; Baud, Damien; François, Patrice; Chuat, Victoria; Chain, Florian; Langella, Philippe; Nicoli, Jacques; Le Loir, Yves; Even, Sergine

    2015-01-01

    Bovine mastitis is a costly disease in dairy cattle worldwide. As of yet, the control of bovine mastitis is mostly based on prevention by thorough hygienic procedures during milking. Additional strategies include vaccination and utilization of antibiotics. Despite these measures, mastitis is not fully under control, thus prompting the need for alternative strategies. The goal of this study was to isolate autochthonous lactic acid bacteria (LAB) from bovine mammary microbiota that exhibit beneficial properties that could be used for mastitis prevention and/or treatment. Sampling of the teat canal led to the isolation of 165 isolates, among which a selection of ten non-redundant LAB strains belonging to the genera Lactobacillus and Lactococcus were further characterized with regard to several properties: surface properties (hydrophobicity, autoaggregation); inhibition potential of three main mastitis pathogens, Staphylococcus aureus, Escherichia coli and Streptococcus uberis; colonization capacities of bovine mammary epithelial cells (bMEC); and immunomodulation properties. Three strains, Lactobacillus brevis 1595 and 1597 and Lactobacillus plantarum 1610, showed high colonization capacities and a medium surface hydrophobicity. These strains are good candidates to compete with pathogens for mammary gland colonization. Moreover, nine strains exhibited anti-inflammatory properties, as illustrated by the lower IL-8 secretion by E. coli-stimulated bMEC in the presence of these LAB. Full genome sequencing of five candidate strains allowed to check for undesirable genetic elements such as antibiotic resistance genes and to identify potential bacterial determinants involved in the beneficial properties. This large screening of beneficial properties while checking for undesirable genetic markers allowed the selection of promising candidate LAB strains from bovine mammary microbiota for the prevention and/or treatment of bovine mastitis. PMID:26713450

  11. Bioactive Molecules Released in Food by Lactic Acid Bacteria: Encrypted Peptides and Biogenic Amines

    PubMed Central

    Pessione, Enrica; Cirrincione, Simona

    2016-01-01

    Lactic acid bacteria (LAB) can produce a huge amount of bioactive compounds. Since their elective habitat is food, especially dairy but also vegetal food, it is frequent to find bioactive molecules in fermented products. Sometimes these compounds can have adverse effects on human health such as biogenic amines (tyramine and histamine), causing allergies, hypertensive crises, and headache. However, some LAB products also display benefits for the consumers. In the present review article, the main nitrogen compounds produced by LAB are considered. Besides biogenic amines derived from the amino acids tyrosine, histidine, phenylalanine, lysine, ornithine, and glutamate by decarboxylation, interesting peptides can be decrypted by the proteolytic activity of LAB. LAB proteolytic system is very efficient in releasing encrypted molecules from several proteins present in different food matrices. Alpha and beta-caseins, albumin and globulin from milk and dairy products, rubisco from spinach, beta-conglycinin from soy and gluten from cereals constitute a good source of important bioactive compounds. These encrypted peptides are able to control nutrition (mineral absorption and oxidative stress protection), metabolism (blood glucose and cholesterol lowering) cardiovascular function (antithrombotic and hypotensive action), infection (microbial inhibition and immunomodulation) and gut-brain axis (opioids and anti-opioids controlling mood and food intake). Very recent results underline the role of food-encrypted peptides in protein folding (chaperone-like molecules) as well as in cell cycle and apoptosis control, suggesting new and positive aspects of fermented food, still unexplored. In this context, the detailed (transcriptomic, proteomic, and metabolomic) characterization of LAB of food interest (as starters, biocontrol agents, nutraceuticals, and probiotics) can supply a solid evidence-based science to support beneficial effects and it is a promising approach as well to obtain

  12. Antifungal Activity of Lactic Acid Bacteria Strains Isolated from Natural Honey against Pathogenic Candida Species.

    PubMed

    Bulgasem, Bulgasem Y; Lani, Mohd Nizam; Hassan, Zaiton; Wan Yusoff, Wan Mohtar; Fnaish, Sumaya G

    2016-12-01

    The role of lactic acid bacteria (LAB) in honey as antifungal activity has received little attention and their mechanism of inhibitory of fungi is not fully understood. In this study, LAB were isolated from honey samples from Malaysia, Libya, Saudi Arabia, and Yemen. Twenty-five isolates were confirmed LAB by catalase test and Gram staining, and were screened for antifungal activity. Four LAB showed inhibitory activity against Candida spp. using the dual agar overlay method. And they were identified as Lactobacillus plantarum HS isolated from Al-Seder honey, Lactobacillus curvatus HH isolated from Al-Hanon honey, Pediococcus acidilactici HC isolated from Tualang honey and Pediococcus pentosaceus HM isolated from Al-Maray honey by the 16S rDNA sequence. The growth of Candida glabrata ATCC 2001 was strongly inhibited (>15.0 mm) and (10~15 mm) by the isolates of L. curvatus HH and P. pentosaceus HM, respectively. The antifungal activity of the crude supernatant (cell free supernatant, CFS) was evaluated using well diffusion method. The CFS showed high antifungal activity against Candida spp. especially The CFS of L. curvatus HH was significantly (p < 0.05) inhibited growth of C. glabrata ATCC 2001, C. parapsilosis ATCC 2201, and C. tropicalis ATCC 750 with inhibitory zone 22.0, 15.6, and 14.7 mm, respectively. While CFS of P. pentosaceus HM was significantly (p < 0.05) effective against C. krusei, C. glabrata, and C. albicans with inhibition zone 17.2, 16.0, and 13.3 mm, respectively. The results indicated that LAB isolated from honey produced compounds which can be used to inhibit the growth of the pathogenic Candida species.

  13. Fighting Off Wound Pathogens in Horses with Honeybee Lactic Acid Bacteria.

    PubMed

    Olofsson, Tobias C; Butler, Éile; Lindholm, Christina; Nilson, Bo; Michanek, Per; Vásquez, Alejandra

    2016-10-01

    In the global perspective of antibiotic resistance, it is urgent to find potent topical antibiotics for the use in human and animal infection. Healing of equine wounds, particularly in the limbs, is difficult due to hydrostatic factors and exposure to environmental contaminants, which can lead to heavy bio-burden/biofilm formation and sometimes to infection. Therefore, antibiotics are often prescribed. Recent studies have shown that honeybee-specific lactic acid bacteria (LAB), involved in honey production, and inhibit human wound pathogens. The aim of this pilot study was to investigate the effects on the healing of hard-to-heal equine wounds after treatment with these LAB symbionts viable in a heather honey formulation. For this, we included ten horses with wound duration of >1 year, investigated the wound microbiota, and treated wounds with the novel honeybee LAB formulation. We identified the microbiota using MALDI-TOF mass spectrometry and DNA sequencing. In addition, the antimicrobial properties of the honeybee LAB formulation were tested against all wound isolates in vitro. Our results indicate a diverse wound microbiota including fifty-three bacterial species that showed 90 % colonization by at least one species of Staphylococcus. Treatment with the formulation promoted wound healing in all cases already after the first application and the wounds were either completely healed (n = 3) in less than 20 days or healing was in progress. Furthermore, the honeybee LAB formulation inhibited all pathogens when tested in vitro. Consequently, this new treatment option presents as a powerful candidate for the topical treatment of hard-to-heal wounds in horses.

  14. Molecular identification and quantification of lactic acid bacteria in traditional fermented dairy foods of Russia.

    PubMed

    Yu, J; Wang, H M; Zha, M S; Qing, Y T; Bai, N; Ren, Y; Xi, X X; Liu, W J; Menghe, B L G; Zhang, H P

    2015-08-01

    Russian traditional fermented dairy foods have been consumed for thousands of years. However, little research has focused on exploiting lactic acid bacteria (LAB) resources and analyzing the LAB composition of Russian traditional fermented dairy foods. In the present study, we cultured LAB isolated from fermented mare and cow milks, sour cream, and cheese collected from Kalmykiya, Buryats, and Tuva regions of Russia. Seven lactobacillus species and the Bifidobacterium genus were quantified by quantitative PCR. The LAB counts in these samples ranged from 3.18 to 9.77 log cfu/mL (or per gram). In total, 599 LAB strains were obtained from these samples using de Man, Rogosa, and Sharpe agar and M17 agar. The identified LAB belonged to 7 genera and 30 species by 16S rRNA and murE gene sequencing and multiplex PCR assay. The predominant LAB isolates were Lactobacillus helveticus (176 strains) and Lactobacillus plantarum (63 strains), which represented 39.9% of all isolates. The quantitative PCR results revealed that counts of 7 lactobacilli species and Bifidobacterium spp. of 30 fermented cow milk samples ranged from 1.19±0.34 (Lactobacillus helveticus in Tuva) to 8.09±0.71 (Lactobacillus acidophilus in Kalmykiya) log cfu/mL of fermented cow milk (mean ± standard error). The numbers of Bifidobacterium spp., Lb. plantarum, Lb. helveticus, and Lb. acidophilus revealed no significant difference between the 3 regions; nevertheless, Lactobacillus paracasei, Lactobacillus fermentum, Lactobacillus sakei, and Lactobacillus delbrueckii ssp. bulgaricus exhibited different degrees of variation across 3 regions. The results demonstrate that traditional fermented dairy products from different regions of Russia have complex compositions of LAB species. The diversity of LAB might be related to the type of fermented dairy product, geographical origin, and manufacturing process.

  15. Survey on the community and dynamics of lactic acid bacteria in Grana Padano cheese.

    PubMed

    Santarelli, Marcela; Bottari, Benedetta; Lazzi, Camilla; Neviani, Erasmo; Gatti, Monica

    2013-12-01

    Grana Padano (GP) is a Protected Designation of Origin cheese made with raw milk and natural whey culture (NWC) that is characterised by a long ripening period. In this study, six GP productions were considered in order to evaluate the trend of microbial dynamics and compare lactic acid bacteria (LAB) population levels in cheeses during the entire cheese-making process. To reach this goal, for each GP production, samples of vat raw milk, NWC and cheeses at 48h, 2, 6, 9 and 13 months were subjected to plate counts and direct counts by fluorescence microscopy, as well as amplicon length heterogeneity-PCR (LH-PCR). Statistical analysis was applied to the results and ecological indices were estimated. It was demonstrated that the LAB able to grow in the cheese-environment conditions could arise from both raw milk and NWC. Starter lactobacilli (SLAB) from NWC were the main species present during acidification, and non-starter LAB (NSLAB), mainly from milk but also from NWC, were able to grow after brining and they dominated during ripening. The peak areas of LH-PCR profiles were used to determine ecological indices during manufacture and ripening. Among cheese ecosystems with different ageing times, diversity, Evenness and Richness were different, with highest bacterial growth and diversity occurring in cheese ripening at 2 months. At this time point, which seemed to be a crucial moment for GP microbial evolution, cell lysis of both SLAB and NSLAB was also observed. Sampling modality and statistical analysis gave greater significance to the results used to describe the microbiological characteristics of a cheese recognised worldwide.

  16. Bacteriocins from lactic acid bacteria and their potential in the preservation of fruit products.

    PubMed

    Barbosa, Ana Andréa Teixeira; Mantovani, Hilário Cuquetto; Jain, Sona

    2017-01-03

    Bacteriocins produced by lactic acid bacteria (LAB) are well-recognized for their potential as natural food preservatives. These antimicrobial peptides usually do not change the sensorial properties of food products and can be used in combination with traditional preservation methods to ensure microbial stability. In recent years, fruit products are increasingly being associated with food-borne pathogens and spoilage microorganisms, and bacteriocins are important candidates to preserve these products. Bacteriocins have been extensively studied to preserve foods of animal origin. However, little information is available for their use in vegetable products, especially in minimally processed ready-to-eat fruits. Although, many bacteriocins possess useful characteristics that can be used to preserve fruit products, to date, only nisin, enterocin AS-48, bovicin HC5, enterocin 416K1, pediocin and bificin C6165 have been tested for their activity against spoilage and pathogenic microorganisms in these products. Among these, only nisin and pediocin are approved to be commercially used as food additives, and their use in fruit products is still limited to certain countries. Considering the increasing demand for fresh-tasting fruit products and concern for public safety, the study of other bacteriocins with biochemical characteristics that make them candidates for the preservation of these products are of great interest. Efforts for their approval as food additives are also important. In this review, we discuss why the study of bacteriocins as an alternative method to preserve fruit products is important; we detail the biotechnological approaches for the use of bacteriocins in fruit products; and describe some bacteriocins that have been tested and have potential to be tested for the preservation of fruit products.

  17. Rapid detection and identification of beer-spoilage lactic acid bacteria by microcolony method.

    PubMed

    Asano, Shizuka; Iijima, Kazumaru; Suzuki, Koji; Motoyama, Yasuo; Ogata, Tomoo; Kitagawa, Yasushi

    2009-08-01

    We evaluated a microcolony method for the detection and identification of beer-spoilage lactic acid bacteria (LAB). In this approach, bacterial cells were trapped on a polycarbonate membrane filter and cultured on ABD medium, a medium that allows highly specific detection of beer-spoilage LAB strains. After short-time incubation, viable cells forming microcolonies were stained with carboxyfluorescein diacetate (CFDA) and counted with muFinder Inspection System. In our study, we first investigated the growth behavior of various beer-spoilage LAB by traditional culture method, and Lactobacillus lindneri and several L. paracollinoides strains were selected as slow growers on ABD medium. Then the detection speeds were evaluated by microcolony method, using these slowly growing strains. As a result, all of the slowly growing beer-spoilage LAB strains were detected within 3 days of incubation. The specificity of this method was found to be exceptionally high and even discriminated intra-species differences in beer-spoilage ability of LAB strains upon detection. These results indicate that our microcolony approach allows rapid and specific detection of beer-spoilage LAB strains with inexpensive CFDA staining. For further confirmation of species status of detected strains, subsequent treatment with species-specific fluorescence in situ hybridization (FISH) probes was shown as effective for identifying the CFDA-detected microcolonies to the species level. In addition, no false-positive results arising from noise signals were recognized for CFDA staining and FISH methods. Taken together, the developed microcolony method was demonstrated as a rapid and highly specific countermeasure against beer-spoilage LAB, and compared favorably with the conventional culture methods.

  18. Regulation of the activity of lactate dehydrogenases from four lactic acid bacteria.

    PubMed

    Feldman-Salit, Anna; Hering, Silvio; Messiha, Hanan L; Veith, Nadine; Cojocaru, Vlad; Sieg, Antje; Westerhoff, Hans V; Kreikemeyer, Bernd; Wade, Rebecca C; Fiedler, Tomas

    2013-07-19

    Despite high similarity in sequence and catalytic properties, the l-lactate dehydrogenases (LDHs) in lactic acid bacteria (LAB) display differences in their regulation that may arise from their adaptation to different habitats. We combined experimental and computational approaches to investigate the effects of fructose 1,6-bisphosphate (FBP), phosphate (Pi), and ionic strength (NaCl concentration) on six LDHs from four LABs studied at pH 6 and pH 7. We found that 1) the extent of activation by FBP (Kact) differs. Lactobacillus plantarum LDH is not regulated by FBP, but the other LDHs are activated with increasing sensitivity in the following order: Enterococcus faecalis LDH2 ≤ Lactococcus lactis LDH2 < E. faecalis LDH1 < L. lactis LDH1 ≤ Streptococcus pyogenes LDH. This trend reflects the electrostatic properties in the allosteric binding site of the LDH enzymes. 2) For L. plantarum, S. pyogenes, and E. faecalis, the effects of Pi are distinguishable from the effect of changing ionic strength by adding NaCl. 3) Addition of Pi inhibits E. faecalis LDH2, whereas in the absence of FBP, Pi is an activator of S. pyogenes LDH, E. faecalis LDH1, and L. lactis LDH1 and LDH2 at pH 6. These effects can be interpreted by considering the computed binding affinities of Pi to the catalytic and allosteric binding sites of the enzymes modeled in protonation states corresponding to pH 6 and pH 7. Overall, the results show a subtle interplay among the effects of Pi, FBP, and pH that results in different regulatory effects on the LDHs of different LABs.

  19. Bioactive Molecules Released in Food by Lactic Acid Bacteria: Encrypted Peptides and Biogenic Amines.

    PubMed

    Pessione, Enrica; Cirrincione, Simona

    2016-01-01

    Lactic acid bacteria (LAB) can produce a huge amount of bioactive compounds. Since their elective habitat is food, especially dairy but also vegetal food, it is frequent to find bioactive molecules in fermented products. Sometimes these compounds can have adverse effects on human health such as biogenic amines (tyramine and histamine), causing allergies, hypertensive crises, and headache. However, some LAB products also display benefits for the consumers. In the present review article, the main nitrogen compounds produced by LAB are considered. Besides biogenic amines derived from the amino acids tyrosine, histidine, phenylalanine, lysine, ornithine, and glutamate by decarboxylation, interesting peptides can be decrypted by the proteolytic activity of LAB. LAB proteolytic system is very efficient in releasing encrypted molecules from several proteins present in different food matrices. Alpha and beta-caseins, albumin and globulin from milk and dairy products, rubisco from spinach, beta-conglycinin from soy and gluten from cereals constitute a good source of important bioactive compounds. These encrypted peptides are able to control nutrition (mineral absorption and oxidative stress protection), metabolism (blood glucose and cholesterol lowering) cardiovascular function (antithrombotic and hypotensive action), infection (microbial inhibition and immunomodulation) and gut-brain axis (opioids and anti-opioids controlling mood and food intake). Very recent results underline the role of food-encrypted peptides in protein folding (chaperone-like molecules) as well as in cell cycle and apoptosis control, suggesting new and positive aspects of fermented food, still unexplored. In this context, the detailed (transcriptomic, proteomic, and metabolomic) characterization of LAB of food interest (as starters, biocontrol agents, nutraceuticals, and probiotics) can supply a solid evidence-based science to support beneficial effects and it is a promising approach as well to obtain

  20. Biodiversity of lactic acid bacteria and yeasts in spontaneously-fermented buckwheat and teff sourdoughs.

    PubMed

    Moroni, Alice V; Arendt, Elke K; Dal Bello, Fabio

    2011-05-01

    In this study, four different laboratory scale gluten-free (GF) sourdoughs were developed from buckwheat or teff flours. The fermentations were initiated by the spontaneous biota of the flours and developed under two technological conditions (A and B). Sourdoughs were propagated by continuous back-slopping until the stability was reached. The composition of the stable biota occurring in each sourdough was assessed using both culture-dependent and -independent techniques. Overall, a broad spectrum of lactic acid bacteria (LAB) and yeasts species, belonging mainly to the genera Lactobacillus, Pediococcus, Leuconostoc, Kazachstania and Candida, were identified in the stable sourdoughs. Buckwheat and teff sourdoughs were dominated mainly by obligate or facultative heterofermentative LAB, which are commonly associated with traditional wheat or rye sourdoughs. However, the spontaneous fermentation of the GF flours resulted also in the selection of species which are not consider endemic to traditional sourdoughs, i.e. Pediococcus pentosaceus, Leuconostoc holzapfelii, Lactobacillus gallinarum, Lactobacillus vaginalis, Lactobacillus sakei, Lactobacillus graminis and Weissella cibaria. In general, the composition of the stable biota was strongly affected by the fermentation conditions, whilst Lactobacillus plantarum dominated in all buckwheat sourdoughs. Lactobacillus pontis is described for the first time as dominant species in teff sourdough. Among yeasts, Saccharomyces cerevisiae and Candida glabrata dominated teff sourdoughs, whereas the solely Kazachstania barnetti was isolated in buckwheat sourdough developed under condition A. This study allowed the identification and isolation of LAB and yeasts species which are highly competitive during fermentation of buckwheat or teff flours. Representatives of these species can be selected as starters for the production of sourdough destined to GF bread production.

  1. Display of recombinant proteins at the surface of lactic acid bacteria: strategies and applications.

    PubMed

    Michon, C; Langella, P; Eijsink, V G H; Mathiesen, G; Chatel, J M

    2016-05-03

    Lactic acid bacteria (LAB) are promising vectors of choice to deliver active molecules to mucosal tissues. They are recognized as safe by the World Health Organization and some strains have probiotic properties. The wide range of potential applications of LAB-driven mucosal delivery includes control of inflammatory bowel disease, vaccine delivery, and management of auto-immune diseases. Because of this potential, strategies for the display of proteins at the surface of LAB are gaining interest. To display a protein at the surface of LAB, a signal peptide and an anchor domain are necessary. The recombinant protein can be attached to the membrane layer, using a transmembrane anchor or a lipoprotein-anchor, or to the cell wall, by a covalent link using sortase mediated anchoring via the LPXTG motif, or by non-covalent liaisons employing binding domains such as LysM or WxL. Both the stability and functionality of the displayed proteins will be affected by the kind of anchor used. The most commonly surfaced exposed recombinant proteins produced in LAB are antigens and antibodies and the most commonly used LAB are lactococci and lactobacilli. Although it is not necessarily so that surface-display is the preferred localization in all cases, it has been shown that for certain applications, such as delivery of the human papillomavirus E7 antigen, surface-display elicits better biological responses, compared to cytosolic expression or secretion. Recent developments include the display of peptides and proteins targeting host cell receptors, for the purpose of enhancing the interactions between LAB and host. Surface-display technologies have other potential applications, such as degradation of biomass, which is of importance for some potential industrial applications of LAB.

  2. Competitive inhibition of Listeria monocytogenes in ready-to-eat meat products by lactic acid bacteria.

    PubMed

    Amézquita, A; Brashears, M M

    2002-02-01

    Forty-nine strains of lactic acid bacteria (LAB), isolated from commercially available ready-to-eat (RTE) meat products, were screened for their ability to inhibit the growth of Listeria monocytogenes at refrigeration (5 degrees C) temperatures on agar spot tests. The three most inhibitory strains were identified as Pediococcus acidilactici, Lactobacillus casei, and Lactobacillus paracasei by 16S rDNA sequence analysis. Their antilisterial activity was quantified in associative cultures in deMan Rogosa Sharpe (MRS) broth at 5 degrees C for 28 days, resulting in a pathogen reduction of 3.5 log10 cycles compared to its initial level. A combined culture of these strains was added to frankfurters and cooked ham coinoculated with L. monocytogenes, vacuum packaged, and stored at 5 degrees C for 28 days. Bacteriostatic activity was observed in cooked ham, whereas bactericidal activity was observed in frankfurters. Numbers of L. monocytogenes were 4.2 to 4.7 log10 and 2.6 log10 cycles lower than controls in frankfurters and cooked ham, respectively, after the 28-day refrigerated storage. In all cases, numbers of LAB increased by only 1 log10 cycle. The strain identified as P. acidilactici was possibly a bacteriocin producer, whereas the antilisterial activity of the other two strains was due to the production of organic acids. There was no significant difference (P > 0.05) in the antilisterial activity detected in frankfurters whether the LAB strains were used individually or as combined cultures. Further studies over a 56-day period indicated no impact on the quality of the product. This method represents a potential antilisterial intervention in RTE meats, because it inhibited the growth of the pathogen at refrigeration temperatures without causing sensory changes.

  3. Proteolytic and antimicrobial activity of lactic acid bacteria grown in goat milk.

    PubMed

    Atanasova, Jivka; Moncheva, Penka; Ivanova, Iskra

    2014-11-02

    We examined 62 strains and 21 trade starter cultures from the collection of LB Bulgaricum PLC for proteolytic and antimicrobial activity of lactic acid bacteria (LAB) grown in goat milk. The aim of this study was to investigate the fermentation of caseins, α-lactalbumin and β-lactoglobulin by LAB, using the o-phthaldialdehyde (OPA) spectrophotometric assay and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The proteolysis targeted mainly caseins, especially β-casein. Whey proteins were proteolyzed, essentially β-lactoglobulin. The proteolytic activity of Lactococcus lactis l598, Streptococcus thermophilus t3D1, Dt1, Lactobacillus lactis 1043 and L. delbrueckii subsp. bulgaricus b38, b122 and b24 was notably high. The proteolysis process gave rise to medium-sized peptide populations. Most of the examined strains showed antimicrobial activity against some food pathogens, such as Escherichia coli, Staphylococcus aureus, Salmonella cholere enteridis, Listeria monocytogenes, Listeria innocua and Enterobacter aerogenes. The most active producers of antimicrobial-active peptides were strains of L. delbrueckii subsp. bulgaricus and S. thermophilus, which are of practical importance. The starter cultures containing the examined species showed high proteolytic and antimicrobial activity in skimmed goat milk. The greatest antimicrobial activity of the cultures was detected against E. aerogenes. The obtained results demonstrated the significant proteolytic potential of the examined strains in goat milk and their potential for application in the production of dairy products from goat's milk. The present results could be considered as the first data on the proteolytic capacity of strains and starter cultures in goat milk for the purposes of trade interest of LB Bulgaricum PLC.

  4. Core Fluxome and Metafluxome of Lactic Acid Bacteria under Simulated Cocoa Pulp Fermentation Conditions

    PubMed Central

    Adler, Philipp; Bolten, Christoph Josef; Dohnt, Katrin; Hansen, Carl Erik

    2013-01-01

    In the present work, simulated cocoa fermentation was investigated at the level of metabolic pathway fluxes (fluxome) of lactic acid bacteria (LAB), which are typically found in the microbial consortium known to convert nutrients from the cocoa pulp into organic acids. A comprehensive 13C labeling approach allowed to quantify carbon fluxes during simulated cocoa fermentation by (i) parallel 13C studies with [13C6]glucose, [1,2-13C2]glucose, and [13C6]fructose, respectively, (ii) gas chromatography-mass spectrometry (GC/MS) analysis of secreted acetate and lactate, (iii) stoichiometric profiling, and (iv) isotopomer modeling for flux calculation. The study of several strains of L. fermentum and L. plantarum revealed major differences in their fluxes. The L. fermentum strains channeled only a small amount (4 to 6%) of fructose into central metabolism, i.e., the phosphoketolase pathway, whereas only L. fermentum NCC 575 used fructose to form mannitol. In contrast, L. plantarum strains exhibited a high glycolytic flux. All strains differed in acetate flux, which originated from fractions of citrate (25 to 80%) and corresponding amounts of glucose and fructose. Subsequent, metafluxome studies with consortia of different L. fermentum and L. plantarum strains indicated a dominant (96%) contribution of L. fermentum NCC 575 to the overall flux in the microbial community, a scenario that was not observed for the other strains. This highlights the idea that individual LAB strains vary in their metabolic contribution to the overall fermentation process and opens up new routes toward streamlined starter cultures. L. fermentum NCC 575 might be one candidate due to its superior performance in flux activity. PMID:23851099

  5. Factors affecting the numbers of expected viable lactic acid bacteria in inoculant applicator tanks.

    PubMed

    Windle, M C; Kung, L

    2016-11-01

    The application of correct numbers of viable microorganisms to forages at the time of ensiling is one of the most important factors affecting the probability of a beneficial effect from an inoculant. The objective of this study was to determine relationships between numbers of expected lactic acid bacteria (LAB) from silage inoculants in application tanks and various factors that might affect their viability. The pH and temperature of inoculant-water mixes were measured in applicator tanks (n=53) on farms in Wisconsin, Minnesota, South Dakota, and California during the corn harvest season of 2012. Samples were collected on-farm and plated on de Man, Rogosa, and Sharpe agar to enumerate LAB and establish the number of viable LAB (cfu/mL). Expected numbers of LAB were calculated from the minimum label guarantees for viable bacteria and mixing rates with water. In addition, the pH of the inoculant-water mixes at sampling, the ambient temperature at sampling, and the length of time that the samples had been in the tank were measured and obtained. The log difference between the measured and expected numbers of LAB was calculated and expressed as ΔM - E in log scale. Ambient temperature at sampling had no relationship with time in the tank or ΔM - E. Most (83%) of the inoculants had been mixed with water in the applicator tanks for <10h. For these samples, a negative linear correlation (R(2)=0.36) existed between time that the inoculant-water mixes were in the applicators tanks and ΔM - E. The pH of the inoculant-water mixes was also negatively correlated (R(2)=0.28) with time in the applicator tank, but pH was not related to ΔM - E. The temperatures of the inoculant-water mixtures were negatively correlated with ΔM - E (R(2)=0.39). Seven of 8 samples whose ΔM - E were at least -0.95 or more lower than expected (equivalent of about 1 or more log concentration less than expected) had water temperatures above 35°C. These data support our previous laboratory findings

  6. Amino acid profiles of lactic acid bacteria, isolated from kefir grains and kefir starter made from them.

    PubMed

    Simova, Emilina; Simov, Zhelyasko; Beshkova, Dora; Frengova, Ginka; Dimitrov, Zhechko; Spasov, Zdravko

    2006-03-15

    The characteristics of cell growth, lactic acid production, amino acid release and consumption by single-strain cultures of lactic acid bacteria (isolated from kefir grains), and by a multiple-strain kefir starter prepared from them, were studied. The change in the levels of free amino acids was followed throughout the kefir process: single-strain kefir bacteria and the kefir starter (Lactococcus lactis C15-1%+Lactobacillus helveticus MP12-3%+(Streptococcus thermophilus T15+Lactobacillus bulgaricus HP1 = 1:1)-3%) were cultivated in pasteurized (92 degrees C for 20 min) cow's milk (3% fat content) at 28 degrees C for 5 h (the kefir starter reached pH 4.7) and subsequently grown at 20 degrees C for 16 h; storage was at 4 degrees C for 168 h. The strain L. helveticus MP12 was unrivaled with respect to free amino acid production (53.38 mg (100 g)(-1)) and cell growth (17.8 x 10(8) CFU ml(-1)); however, it manifested the lowest acidification activity. L. bulgaricus HP1 released approximately 3.7 times less amino acids, nearly 5 times lower cell growth, and produced about 1.2 times more lactic acid. S. thermophilus T15 demonstrated dramatically complex amino acid necessities for growth and metabolism. With L. lactis C15, the highest levels of growth and lactic acid synthesis were recorded (18.3 x 10(8) CFU ml(-1) and 7.8 g l(-1) lactic acid at the 21st hour), and as for free amino acid production, it approximated L. bulgaricus HP1 (17.03 mg (100 g)(-1) maximum concentration). In the L. lactis C15 culture, the amino acids were used more actively throughout the first exponential growth phase (by the 10th hour) than during the second growth phase. The unique properties of the L. helveticus MP12 strain to produce amino acids were employed to create a symbiotic bioconsortium kefir culture, which, under conditions of kefir formation, enhanced lactic acid production and shortened the time required to reach pH 4.7; intensified cell growth activity, resulting in a respective 90

  7. Diversity and Habitat Preferences of Cultivated and Uncultivated Aerobic Methanotrophic Bacteria Evaluated Based on pmoA as Molecular Marker

    PubMed Central

    Knief, Claudia

    2015-01-01

    Methane-oxidizing bacteria are characterized by their capability to grow on methane as sole source of carbon and energy. Cultivation-dependent and -independent methods have revealed that this functional guild of bacteria comprises a substantial diversity of organisms. In particular the use of cultivation-independent methods targeting a subunit of the particulate methane monooxygenase (pmoA) as functional marker for the detection of aerobic methanotrophs has resulted in thousands of sequences representing “unknown methanotrophic bacteria.” This limits data interpretation due to restricted information about these uncultured methanotrophs. A few groups of uncultivated methanotrophs are assumed to play important roles in methane oxidation in specific habitats, while the biology behind other sequence clusters remains still largely unknown. The discovery of evolutionary related monooxygenases in non-methanotrophic bacteria and of pmoA paralogs in methanotrophs requires that sequence clusters of uncultivated organisms have to be interpreted with care. This review article describes the present diversity of cultivated and uncultivated aerobic methanotrophic bacteria based on pmoA gene sequence diversity. It summarizes current knowledge about cultivated and major clusters of uncultivated methanotrophic bacteria and evaluates habitat specificity of these bacteria at different levels of taxonomic resolution. Habitat specificity exists for diverse lineages and at different taxonomic levels. Methanotrophic genera such as Methylocystis and Methylocaldum are identified as generalists, but they harbor habitat specific methanotrophs at species level. This finding implies that future studies should consider these diverging preferences at different taxonomic levels when analyzing methanotrophic communities. PMID:26696968

  8. Diversity and Habitat Preferences of Cultivated and Uncultivated Aerobic Methanotrophic Bacteria Evaluated Based on pmoA as Molecular Marker.

    PubMed

    Knief, Claudia

    2015-01-01

    Methane-oxidizing bacteria are characterized by their capability to grow on methane as sole source of carbon and energy. Cultivation-dependent and -independent methods have revealed that this functional guild of bacteria comprises a substantial diversity of organisms. In particular the use of cultivation-independent methods targeting a subunit of the particulate methane monooxygenase (pmoA) as functional marker for the detection of aerobic methanotrophs has resulted in thousands of sequences representing "unknown methanotrophic bacteria." This limits data interpretation due to restricted information about these uncultured methanotrophs. A few groups of uncultivated methanotrophs are assumed to play important roles in methane oxidation in specific habitats, while the biology behind other sequence clusters remains still largely unknown. The discovery of evolutionary related monooxygenases in non-methanotrophic bacteria and of pmoA paralogs in methanotrophs requires that sequence clusters of uncultivated organisms have to be interpreted with care. This review article describes the present diversity of cultivated and uncultivated aerobic methanotrophic bacteria based on pmoA gene sequence diversity. It summarizes current knowledge about cultivated and major clusters of uncultivated methanotrophic bacteria and evaluates habitat specificity of these bacteria at different levels of taxonomic resolution. Habitat specificity exists for diverse lineages and at different taxonomic levels. Methanotrophic genera such as Methylocystis and Methylocaldum are identified as generalists, but they harbor habitat specific methanotrophs at species level. This finding implies that future studies should consider these diverging preferences at different taxonomic levels when analyzing methanotrophic communities.

  9. Cultivable microbiota of Lithobates catesbeianus and advances in the selection of lactic acid bacteria as biological control agents in raniculture.

    PubMed

    Mendoza, Gabriela Montel; Pasteris, Sergio E; Ale, Cesar E; Otero, María C; Bühler, Marta I; Nader-Macías, María E Fátima

    2012-12-01

    The cultivable microbiota of skin and cloaca of captive Lithobates catesbeianus includes microorganisms generally accepted as beneficial and potentially pathogenic bacteria. In order to select a group of potentially probiotic bacteria, 136 isolates were evaluated for their surface properties and production of antagonistic metabolites. Then, 11 lactic acid bacteria (LAB) strains were selected and identified as Lactobacillus plantarum, Lb. brevis, Pediococcus pentosaceus, Lactococcus lactis, L. garvieae and Enterococcus gallinarum. Studies of compatibility indicate that all the strains could be included in a multi-strain probiotic, with the exception of Ent. gallinarum CRL 1826 which inhibited LAB species through a bacteriocin-like metabolite. These results contribute to the design of a probiotic product to improve the sanitary status of bullfrogs in intensive culture systems, to avoid the use of antibiotics and thus to reduce production costs. It could also be an alternative to prevent infectious diseases during the ex situ breeding of amphibian species under threat of extinction.

  10. Lactic acid permeabilizes gram-negative bacteria by disrupting the outer membrane.

    PubMed

    Alakomi, H L; Skyttä, E; Saarela, M; Mattila-Sandholm, T; Latva-Kala, K; Helander, I M

    2000-05-01

    The effect of lactic acid on the outer membrane permeability of Escherichia coli O157:H7, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium was studied utilizing a fluorescent-probe uptake assay and sensitization to bacteriolysis. For control purposes, similar assays were performed with EDTA (a permeabilizer acting by chelation) and with hydrochloric acid, the latter at pH values corresponding to those yielded by lactic acid, and also in the presence of KCN. Already 5 mM (pH 4.0) lactic acid caused prominent permeabilization in each species, the effect in the fluorescence assay being stronger than that of EDTA or HCl. Similar results were obtained in the presence of KCN, except for P. aeruginosa, for which an increase in the effect of HCl was observed in the presence of KCN. The permeabilization by lactic and hydrochloric acid was partly abolished by MgCl(2). Lactic acid sensitized E. coli and serovar Typhimurium to the lytic action of sodium dodecyl sulfate (SDS) more efficiently than did HCl, whereas both acids sensitized P. aeruginosa to SDS and to Triton X-100. P. aeruginosa was effectively sensitized to lysozyme by lactic acid and by HCl. Considerable proportions of lipopolysaccharide were liberated from serovar Typhimurium by these acids; analysis of liberated material by electrophoresis and by fatty acid analysis showed that lactic acid was more active than EDTA or HCl in liberating lipopolysaccharide from the outer membrane. Thus, lactic acid, in addition to its antimicrobial property due to the lowering of the pH, also functions as a permeabilizer of the gram-negative bacterial outer membrane and may act as a potentiator of the effects of other antimicrobial substances.

  11. Lactic Acid Permeabilizes Gram-Negative Bacteria by Disrupting the Outer Membrane

    PubMed Central

    Alakomi, H.-L.; Skyttä, E.; Saarela, M.; Mattila-Sandholm, T.; Latva-Kala, K.; Helander, I. M.

    2000-01-01

    The effect of lactic acid on the outer membrane permeability of Escherichia coli O157:H7, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium was studied utilizing a fluorescent-probe uptake assay and sensitization to bacteriolysis. For control purposes, similar assays were performed with EDTA (a permeabilizer acting by chelation) and with hydrochloric acid, the latter at pH values corresponding to those yielded by lactic acid, and also in the presence of KCN. Already 5 mM (pH 4.0) lactic acid caused prominent permeabilization in each species, the effect in the fluorescence assay being stronger than that of EDTA or HCl. Similar results were obtained in the presence of KCN, except for P. aeruginosa, for which an increase in the effect of HCl was observed in the presence of KCN. The permeabilization by lactic and hydrochloric acid was partly abolished by MgCl2. Lactic acid sensitized E. coli and serovar Typhimurium to the lytic action of sodium dodecyl sulfate (SDS) more efficiently than did HCl, whereas both acids sensitized P. aeruginosa to SDS and to Triton X-100. P. aeruginosa was effectively sensitized to lysozyme by lactic acid and by HCl. Considerable proportions of lipopolysaccharide were liberated from serovar Typhimurium by these acids; analysis of liberated material by electrophoresis and by fatty acid analysis showed that lactic acid was more active than EDTA or HCl in liberating lipopolysaccharide from the outer membrane. Thus, lactic acid, in addition to its antimicrobial property due to the lowering of the pH, also functions as a permeabilizer of the gram-negative bacterial outer membrane and may act as a potentiator of the effects of other antimicrobial substances. PMID:10788373

  12. Space agriculture for habitation on Mars with hyper-thermophilic aerobic composting bacteria

    NASA Astrophysics Data System (ADS)

    Space Agriculture Task Force; Ishikawa, Y.; Tomita-Yokotani, K.; Hashimoto, H.; Kitaya, Y.; Yamashita, M.; Nagatomo, M.; Oshima, T.; Wada, H.

    Manned Mars exploration, especially for extended periods of time, will require recycle of materials to support human life. Here, a conceptual design is developed for a Martian agricultural system driven by biologically regenerative functions. One of the core biotechnologies function is the use of hyper-thermophilic aerobic composting bacterial ecology. These thermophilic bacteria can play an important role in increasing the effectiveness of the processing of human metabolic waste and inedible biomass and of converting them to fertilizer for the cultivation of plants. This microbial technology has been already well established for the purpose of processing sewage and waste materials for small local communities in Japan. One of the characteristics of the technology is that the metabolic heat release that occurs during bacterial fermentation raises the processing temperature sufficiently high at 80 100 °C to support hyper-thermophilic bacteria. Such a hyper-thermophilic system is found to have great capability of decomposing wastes including even their normally recalcitrant components, in a reasonably short period of time and of providing a better quality of fertilizer as an end-product. High quality compost has been shown to be a key element in creating a healthy regenerative food production system. In ground-based studies, the soil microbial ecology after the addition of high quality compost was shown to improve plant growth and promote a healthy symbiosis of arbuscular mycorrhizal fungi. Another advantage of such high processing temperature is the ability to sterilize the pathogenic organisms through the fermentation process and thus to secure the hygienic safety of the system. Plant cultivation is one of the other major systems. It should fully utilize solar energy received on the Martian surface for supplying energy for photosynthesis. Subsurface water and atmospheric carbon dioxide mined on Mars should be also used in the plant cultivation system. Oxygen and

  13. Isolation of Optically Targeted Single Bacteria by Application of Fluidic Force Microscopy to Aerobic Anoxygenic Phototrophs from the Phyllosphere

    PubMed Central

    Stiefel, Philipp; Zambelli, Tomaso

    2013-01-01

    In their natural environment, bacteria often behave differently than they do under laboratory conditions. To gain insight into the physiology of bacteria in situ, dedicated approaches are required to monitor their adaptations and specific behaviors under environmental conditions. Optical microscopy is crucial for the observation of fundamental characteristics of bacteria, such as cell shape, size, and marker gene expression. Here, fluidic force microscopy (FluidFM) was exploited to isolate optically selected bacteria for subsequent identification and characterization. In this study, bacteriochlorophyll-producing bacteria, which can be visualized due to their characteristic fluorescence in the infrared range, were isolated from leaf washes. Bacterial communities from the phyllosphere were investigated because they harbor genes indicative of aerobic anoxygenic photosynthesis. Our data show that different species of Methylobacterium express their photosystem in planta, and they show a distinct pattern of bacteriochlorophyll production under laboratory conditions that is dependent on supplied carbon sources. PMID:23770907

  14. In vitro Characterization of Bacteriocin Produced by Lactic Acid Bacteria Isolated from Nem Chua, a Traditional Vietnamese Fermented Pork.

    PubMed

    Pilasombut, Komkhae; Rumjuankiat, Kittaporn; Ngamyeesoon, Nualphan; Duy, Le Nguyen Doan

    2015-01-01

    The aim of this study was to screen and In vitro characterize the properties of bacteriocin produced by lactic acid bacteria isolated from Vietnamese fermented pork (Nem chua). One hundred and fifty LAB were isolated from ten samples of Nem chua and screened for bacteriocin-producing lactic acid bacteria. Antimicrobial activity of bacteriocin was carried out by spot on lawn method against both gram positive and gram negative bacteria. One isolate, assigned as KL-1, produced bacteriocin and showed inhibitory activity against Lactobacillus sakei, Leuconostoc mesenteroides and Enterococcus faecalis. To characterize the bacteriocin-producing strain, optimum temperature, incubation period for maximum bacteriocin production and identification of bacteriocin-producing strain were determined. It was found that the optimum cultivation temperature of the strain to produce the maximum bacteriocin activity (12,800 AU/mL) was obtained at 30℃. Meanwhile, bacteriocin production at 6,400 AU/mL was found when culturing the strain at 37℃ and 42℃. The isolate KL-1 was identified as L. plantarum. Antimicrobial activity of cell-free supernatant was completely inhibited by proteolytic enzyme of trypsin, alpha-chymotrypsin and proteinase K. Bacteriocin activity was stable at high temperature up to 100℃ for 10 min and at 4℃ storage for 2 d. However, the longer heating at 100℃ and 4℃ storage, its activity was reduced.

  15. A PCR assay for detection of acetic acid-tolerant lactic acid bacteria in acidic food products.

    PubMed

    Nakano, Shigeru; Matsumura, Atsushi; Yamada, Toshihiro

    2004-03-01

    A PCR assay for the detection of acetic acid-tolerant lactic acid bacteria in the genera of Lactobacillus and Pediococcus was developed in this study. Primers targeting the bacterial 16S rRNA gene were newly designed and used in this PCR assay. To determine the specificity of the assay, 56 different bacterial strains (of 33 genera), 2 fungi, 3 animals, and 4 plants were tested. Results were positive for most tested bacterial members of 16S rRNA gene-based phylogenetic groups (classified in the Lactobacillus casei and Pediococcus group), including Lactobacillus fructivorans, Lactobacillus brevis, Lactobacillus buchneri, Lactobacillus plantarum, and Lactobacillus paracasei. For all other bacterial strains and eukaryote tested, results were negative. Bacterial DNA for PCR was prepared with a simple procedure with the use of Chelex 100 resin from culture after growth in deMan Rogosa Sharpe broth (pH 6.0). To test this PCR assay for the monitoring of the acetic acid-tolerant lactic acid bacteria, L. fructivorans was inoculated into several acidic food as an indicator. Before the PCR, the inoculation of 10 to 50 CFU of bacteria per g of food was followed by a 28-h enrichment culture step, and the PCR assay allowed the detection of bacterial cells. Including the enrichment culture step, the entire PCR detection process can be completed within 30 h.

  16. Selection of lactic acid bacteria isolated from Tunisian cereals and exploitation of the use as starters for sourdough fermentation.

    PubMed

    Mamhoud, Asma; Nionelli, Luana; Bouzaine, Taroub; Hamdi, Moktar; Gobbetti, Marco; Rizzello, Carlo Giuseppe

    2016-05-16

    Wheat bread is the most popular staple food consumed in Tunisia and, despite the niche production of some typical breads (e.g. Tabouna, Mlawi, Mtabga), the major part is currently produced with baker's yeast at industrial or, mainly, at artisanal level, while the use of sourdough fermentation is rarely reported. Considering the growing national demand for cereal baked goods, it can be hypothesized that sourdough fermentation through the use of selected lactic acid bacteria as starters could improve the overall quality and the diversification of local products. Different cereal grains were collected from the regions of Ariana, Bizerta, Beja Nabeul, and Seliana, and the autochthonous lactic acid bacteria were isolated, identified, characterized and selected on the basis of the kinetics of acidification, the proteolytic activity, and the quotient of fermentation. Lactobacillus curvatus MA2, Pediococcus pentosaceus OA2, and Pediococcus acidilactici O1A1 were used together as mixed starter to obtain a selected sourdough. According to the backslopping procedure, a type I sourdough was made from a Tunisian flour (spontaneous sourdough). Compared to the use of the spontaneous sourdough, the one obtained with selected and mixed starters by a unique fermentation step, favored the increase of the concentrations of organic acids, phenols, and total free amino acids, the most suitable quotient of fermentation, and the most intense phytase and antioxidant activities, that increased ca. 20% compared to the control. Moreover, the selected starters improved the in vitro protein digestibility (ca. 82% when selected sourdough was used), textural and sensory features of the breads, as determined by textural profile analysis and panel test, respectively. This study aimed at exploiting the potential of selected autochthonous lactic acid bacteria and extending the use of a sourdough (type II), thanks to the set-up of a two-step fermentation protocol designed for application at the

  17. Using In Vitro Immunomodulatory Properties of Lactic Acid Bacteria for Selection of Probiotics against Salmonella Infection in Broiler Chicks.

    PubMed

    Feng, Junchang; Wang, Lihong; Zhou, Luoxiong; Yang, Xin; Zhao, Xin

    2016-01-01

    Poultry is known to be a major reservoir of Salmonella. The use of lactic acid bacteria has become one of successful strategies to control Salmonella in poultry. The purpose of this study was to select lactic acid bacteria strains by their in vitro immunomodulatory properties for potential use as probiotics against Salmonella infection in broiler chicks. Among 101 isolated lactic acid bacteria strains, 13 strains effectively survived under acidic (pH 2.5) and bile salt (ranging from 0.1% to 1.0%) conditions, effectively inhibited growth of 6 pathogens, and adhered to Caco-2 cells. However, their in vitro immunomodulatory activities differed significantly. Finally, three strains with higher in vitro immunomodulatory properties (Lactobacillus plantarum PZ01, Lactobacillus salivarius JM32 and Pediococcus acidilactici JH231) and three strains with lower in vitro immunomodulatory activities (Enterococcus faecium JS11, Lactobacillus salivarius JK22 and Lactobacillus salivarius JM2A1) were compared for their inhibitory effects on Salmonella adhesion and invasion to Caco-2 cells in vitro and their antimicrobial effects in vivo. The former three strains inhibited Salmonella adhesion and invasion to Caco-2 cells in vitro, reduced the number of Salmonella in intestinal content, spleen and liver, reduced the levels of lipopolysaccharide-induced TNF-α factor (LITAF), IL-1β, IL-6 and IL-12 in serum and increased the level of IL-10 in serum during a challenge study in vivo more efficiently than the latter three strains. These results suggest that in vitro immunomodulatory activities could be used as additional parameters to select more effective probiotics as feed supplements for poultry.

  18. Hydroxycinnamic Acids Used as External Acceptors of Electrons: an Energetic Advantage for Strictly Heterofermentative Lactic Acid Bacteria

    PubMed Central

    Filannino, Pasquale; Gobbetti, Marco; De Angelis, Maria

    2014-01-01

    The metabolism of hydroxycinnamic acids by strictly heterofermentative lactic acid bacteria (19 strains) was investigated as a potential alternative energy route. Lactobacillus curvatus PE5 was the most tolerant to hydroxycinnamic acids, followed by strains of Weissella spp., Lactobacillus brevis, Lactobacillus fermentum, and Leuconostoc mesenteroides, for which the MIC values were the same. The highest sensitivity was found for Lactobacillus rossiae strains. During growth in MRS broth, lactic acid bacteria reduced caffeic, p-coumaric, and ferulic acids into dihydrocaffeic, phloretic, and dihydroferulic acids, respectively, or decarboxylated hydroxycinnamic acids into the corresponding vinyl derivatives and then reduced the latter compounds to ethyl compounds. Reductase activities mainly emerged, and the activities of selected strains were further investigated in chemically defined basal medium (CDM) under anaerobic conditions. The end products of carbon metabolism were quantified, as were the levels of intracellular ATP and the NAD+/NADH ratio. Electron and carbon balances and theoretical ATP/glucose yields were also estimated. When CDM was supplemented with hydroxycinnamic acids, the synthesis of ethanol decreased and the concentration of acetic acid increased. The levels of these metabolites reflected on the alcohol dehydrogenase and acetate kinase activities. Overall, some biochemical traits distinguished the common metabolism of strictly heterofermentative strains: main reductase activity toward hydroxycinnamic acids, a shift from alcohol dehydrogenase to acetate kinase activities, an increase in the NAD+/NADH ratio, and the accumulation of supplementary intracellular ATP. Taken together, the above-described metabolic responses suggest that strictly heterofermentative lactic acid bacteria mainly use hydroxycinnamic acids as external acceptors of electrons. PMID:25261518

  19. Hydroxycinnamic acids used as external acceptors of electrons: an energetic advantage for strictly heterofermentative lactic acid bacteria.

    PubMed

    Filannino, Pasquale; Gobbetti, Marco; De Angelis, Maria; Di Cagno, Raffaella

    2014-12-01

    The metabolism of hydroxycinnamic acids by strictly heterofermentative lactic acid bacteria (19 strains) was investigated as a potential alternative energy route. Lactobacillus curvatus PE5 was the most tolerant to hydroxycinnamic acids, followed by strains of Weissella spp., Lactobacillus brevis, Lactobacillus fermentum, and Leuconostoc mesenteroides, for which the MIC values were the same. The highest sensitivity was found for Lactobacillus rossiae strains. During growth in MRS broth, lactic acid bacteria reduced caffeic, p-coumaric, and ferulic acids into dihydrocaffeic, phloretic, and dihydroferulic acids, respectively, or decarboxylated hydroxycinnamic acids into the corresponding vinyl derivatives and then reduced the latter compounds to ethyl compounds. Reductase activities mainly emerged, and the activities of selected strains were further investigated in chemically defined basal medium (CDM) under anaerobic conditions. The end products of carbon metabolism were quantified, as were the levels of intracellular ATP and the NAD(+)/NADH ratio. Electron and carbon balances and theoretical ATP/glucose yields were also estimated. When CDM was supplemented with hydroxycinnamic acids, the synthesis of ethanol decreased and the concentration of acetic acid increased. The levels of these metabolites reflected on the alcohol dehydrogenase and acetate kinase activities. Overall, some biochemical traits distinguished the common metabolism of strictly heterofermentative strains: main reductase activity toward hydroxycinnamic acids, a shift from alcohol dehydrogenase to acetate kinase activities, an increase in the NAD(+)/NADH ratio, and the accumulation of supplementary intracellular ATP. Taken together, the above-described metabolic responses suggest that strictly heterofermentative lactic acid bacteria mainly use hydroxycinnamic acids as external acceptors of electrons.

  20. Safety assessment of dairy microorganisms: aerobic coryneform bacteria isolated from the surface of smear-ripened cheeses.

    PubMed

    Denis, Catherine; Irlinger, Françoise

    2008-09-01

    The group of "coryneform bacteria" belongs to the class of Actinobacteria including a diverse and heterogeneous collection of bacteria of various genera. Most of them are known as environmental residents and/or commensal flora of humans and they are isolated frequently in clinical studies. Actinobacteria include also several aerobic species, present at the surface of smear-ripened cheeses for decades and used as ripening culture in the dairy industry. Their clinical significance is controversial because an easy combination of phenotypic and molecular methods to characterize Actinobacteria at the species level is still lacking. A bibliographical survey was conducted to assess the safety status of Actinobacteria species used as starter culture in fermented dairy foods, according to their technological interest. Aerobic coryneform bacteria isolated from smear-ripened cheeses are most commonly recovered from soil, the environment or food. To date, no clinical infection or food toxi-infection related to smear cheese coryneform bacteria ingestion has been reported. From a taxonomic viewpoint, dairy species are distant from the reference species associated with known pathologies. From a physiological viewpoint, cheese smear coryneform bacteria appear to be related to particular ecological niches: they are all oxidative species, and most are psychrotrophic and unable to grow at 37 degrees C whereas medically relevant coryneform bacteria are facultative anaerobes and grow at 35-37 degrees C. Consequently, technological strains must be selected according to taxonomic criteria (nonpathogenic species) and ecological criteria.

  1. Organic osmolytes in aerobic bacteria from mono lake, an alkaline, moderately hypersaline environment.

    PubMed

    Ciulla, R A; Diaz, M R; Taylor, B F; Roberts, M F

    1997-01-01

    The identity and concentrations of intracellular organic solutes were determined by nuclear magnetic resonance spectroscopy for two strains of aerobic, gram-negative bacteria isolated from Mono Lake, Calif., an alkaline, moderately hypersaline lake. Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) was the major endogenous solute in both organisms. Concentrations of ectoine varied with external NaCl levels in strain ML-D but not in strain ML-G, where the level was high but invariant from 1.5 to 3.0 M NaCl. Hydroxyectoine also occurred in strain ML-D, especially at elevated NaCl concentrations (2.5 and 3.0 M), but at levels lower than those of ectoine. Exogenous organic solutes that might occur in Mono Lake were examined for their effects on the de novo synthesis of ectoine. Dimethylsulfoniopropionate (DMSP) (0.1 or 1 mM) did not significantly lower ectoine levels in either isolate, and only strain ML-G showed any capacity for DMSP accumulation. With nitrogen limitation, however, DMSP (0.1 mM) substituted for ectoine in strain ML-G and became the main organic solute. Glycine betaine (GB) was more effective than DMSP in affecting ectoine levels, principally in strain ML-D. Strain ML-D accumulated GB to 50 or 67% of its organic solute pool at 2.5 M NaCl, at an external level of 0.1 or 1 mM GB, respectively. Strain ML-D also accumulated arsenobetaine. The methylated zwitterionic compounds, probably metabolic products of phytoplankton (DMSP and GB) or brine shrimps (arsenobetaine) in Mono Lake, may function as osmolytes for indigenous bacteria when present at high concentrations or under conditions of nitrogen limitation or salt stress.

  2. Spatial and temporal variability of aerobic anoxygenic photoheterotrophic bacteria along the east coast of Australia.

    PubMed

    Bibiloni-Isaksson, Jaime; Seymour, Justin R; Ingleton, Tim; van de Kamp, Jodie; Bodrossy, Levente; Brown, Mark V

    2016-12-01

    Aerobic Anoxygenic Phototrophic Bacteria (AAnPB) are ecologically important microorganisms, widespread in oceanic photic zones. However, the key environmental drivers underpinning AAnPB abundance and diversity are still largely undefined. The temporal patterns in AAnPB dynamics at three oceanographic reference stations spanning at approximately 15° latitude along the Australian east coast were examined. AAnPB abundance was highly variable, with pufM gene copies ranging from 1.1 × 10(2) to 1.4 × 10(5) ml(-1) and positively correlated with day length and solar radiation. pufM gene Miseq sequencing revealed that the majority of sequences were closely related to those obtained previously, suggesting that key AAnPB groups are widely distributed across similar environments globally. Temperature was a major structuring factor for AAnPB assemblages across large spatial scales, correlating positively with richness and Gammaproteobacteria (phylogroup K) abundance but negatively with Roseobacter-clade (phylogroup E) abundance, with temperatures between 16°C and 18°C identified as a potential transition zone between these groups. Network analysis revealed that discrete AAnPB populations exploit specific niches defined by varying temperature, light and nutrient conditions in the Tasman Sea system, with evidence for both niche sharing and partitioning amongst closely related operational taxonomic units.

  3. Effects of exogenous aerobic bacteria on methane production and biodegradation of municipal solid waste in bioreactors.

    PubMed

    Ge, Sai; Liu, Lei; Xue, Qiang; Yuan, Zhiming

    2016-09-01

    Landfill is the most common and efficient ways of municipal solid waste (MSW) disposal and the landfill biogas, mostly methane, is currently utilized to generate electricity and heat. The aim of this work is to study the effects and the role of exogenous aerobic bacteria mixture (EABM) on methane production and biodegradation of MSW in bioreactors. The results showed that the addition of EABM could effectively enhance hydrolysis and acidogenesis processes of MSW degradation, resulting in 63.95% reduction of volatile solid (VS), the highest methane production rate (89.83Lkg(-1) organic matter) ever recorded and a threefold increase in accumulative methane production (362.9L) than the control (127.1L). In addition, it is demonstrated that white-rot fungi (WRF) might further promote the methane production through highly decomposing lignin, but the lower pH value in leachate and longer acidogenesis duration may cause methane production reduced. The data demonstrated that methane production and biodegradation of MSW in bioreactors could be significantly enhanced by EABM via enhanced hydrolysis and acidogenesis processes, and the results are of great economic importance for the future design and management of landfill.

  4. Regulation of beta-galactoside transport and accumulation in heterofermentative lactic acid bacteria.

    PubMed Central

    Romano, A H; Brino, G; Peterkofsky, A; Reizer, J

    1987-01-01

    Galactose-grown cells of the heterofermentative lactic acid bacteria Lactobacillus brevis and Lactobacillus buchneri transported methyl-beta-D-thiogalactopyranoside (TMG) by an active transport mechanism and accumulated intracellular free TMG when provided with an exogenous source of energy, such as arginine. The intracellular concentration of TMG resultant under these conditions was approximately 20-fold higher than that in the medium. In contrast, the provision of energy by metabolism of glucose, gluconate, or glucosamine promoted a rapid but transient uptake of TMG followed by efflux that established a low cellular concentration of the galactoside, i.e., only two- to fourfold higher than that in the medium. Furthermore, the addition of glucose to cells preloaded with TMG in the presence of arginine elicited a rapid efflux of the intracellular galactoside. The extent of cellular TMG displacement and the duration of the transient effect of glucose on TMG transport were related to the initial concentration of glucose in the medium. Exhaustion of glucose from the medium restored uptake and accumulation of TMG, providing arginine was available for ATP generation. The nonmetabolizable sugar 2-deoxyglucose elicited efflux of TMG from preloaded cells of L. buchneri but not from those of L. brevis. Phosphorylation of this glucose analog was catalyzed by cell extracts of L. buchneri but not by those of L. brevis. Iodoacetate, at a concentration that inhibits growth and ATP production from glucose, did not prevent efflux of cellular TMG elicited by glucose. The results suggested that a phosphorylated metabolite(s) at or above the level of glyceraldehyde-3-phosphate was required to evoke displacement of intracellular TMG from the cells. Counterflow experiments suggested that glucose converted the active uptake of TMG in L. brevis to a facilitated diffusion mechanism that allowed equilibrium of TMG between the extra- and intracellular milieux. The means by which glucose

  5. Monitoring of wheat lactic acid bacteria from the field until the first step of dough fermentation.

    PubMed

    Alfonzo, Antonio; Miceli, Claudia; Nasca, Anna; Franciosi, Elena; Ventimiglia, Giusi; Di Gerlando, Rosalia; Tuohy, Kieran; Francesca, Nicola; Moschetti, Giancarlo; Settanni, Luca

    2017-04-01

    The present work was carried out to retrieve the origin of lactic acid bacteria (LAB) in sourdough. To this purpose, wheat LAB were monitored from ear harvest until the first step of fermentation for sourdough development. The influence of the geographical area and variety on LAB species/strain composition was also determined. The ears of four Triticum durum varieties (Duilio, Iride, Saragolla and Simeto) were collected from several fields located within the Palermo province (Sicily, Italy) and microbiologically investigated. In order to trace the transfer of LAB during the consecutive steps of manipulation, ears were transformed aseptically and, after threshing, milling and fermentation, samples of kernels, semolinas and doughs, respectively, were analysed. LAB were not found to dominate the microbial communities of the raw materials. In general, kernels harboured lower levels of microorganisms than ears and ears than semolinas. Several samples showing no development of LAB colonies acidified the enrichment broth suggesting the presence of LAB below the detection limit. After fermentation, LAB loads increased consistently for all doughs, reaching levels of 7.0-7.5 Log CFU/g on M17. The values of pH (5.0) and TTA (5.6 mL NaOH/10 g of dough) indicated the occurrence of the acidification process for several doughs. LAB were phenotypically and genotypically differentiated by randomly amplified polymorphic DNA (RAPD)-PCR into eight groups including 51 strains belonging to the species Lactobacillus brevis, Lactobacillus coryniformis, Lactobacillus plantarum, Lactococcus lactis, Lactococcus garvieae, Enterococcus casseliflavus, Enterococcus faecium, Leuconostoc citreum, and Pediococcus pentosaceus. Lactobacilli constituted a minority the LAB community, while lactococci represented more than 50% of strains. Lower LAB complexity was found on kernels, while a richer biodiversity was observed in semolinas and fermented doughs. For broader microbiota characterisation in

  6. Specific Strains of Lactic Acid Bacteria Differentially Modulate the Profile of Adipokines In Vitro.

    PubMed

    Fabersani, Emanuel; Abeijon-Mukdsi, María Claudia; Ross, Romina; Medina, Roxana; González, Silvia; Gauffin-Cano, Paola

    2017-01-01

    Obesity induces local/systemic inflammation accompanied by increases in macrophage infiltration into adipose tissue and production of inflammatory cytokines, chemokines, and hormones. Previous studies have shown that probiotics could improve the intestinal dysbiosis induced by metabolic diseases such as obesity, diabetes, and metabolic syndrome. Microorganisms could (directly or indirectly) affect adipokine levels due to their capacity to induce translocation of several intestinal microbial antigens into systemic circulation, which could lead to metabolic endotoxemia or produce immunomodulation in different organs. The aim of the present study was to select non-inflammatory lactic acid bacteria (LAB) strains with the capacity to modulate adipokine secretion by the adipose tissue. We wish to elucidate the role of potential probiotic strains in the regulation of the cross talking between immune cells such as macrophages and adipose cells. Mouse macrophage cell line RAW 264.7 was used for evaluating the ability of 14 LAB strains to induce cytokine production. The LAB strains were chosen based on their previously studied beneficial properties in health. Then, in murine adipocyte culture and macrophage-adipocyte coculture, we determined the ability of these strains to induce cytokines and leptin secretion. Tumor necrosis factor alpha, interleukin 6 (IL-6), IL-10, monocyte chemoattractant protein-1, and leptin levels were measured in cell supernatants. We also performed the detection and quantification of leptin receptor (Ob-Rb) expression in macrophage cell lines stimulated by these LAB strains. Differential secretion profile of cytokines in macrophage cells induced by LAB strains was observed. Also, the levels of Ob-Rb expression diverged among different LAB strains. In LAB-stimulated coculture cells (adipocytes and macrophages), we observed differential production of leptin and cytokines. Furthermore, we detected lower production levels in single culture than

  7. Phytic acid degrading lactic acid bacteria in tef-injera fermentation.

    PubMed

    Fischer, Maren M; Egli, Ines M; Aeberli, Isabelle; Hurrell, Richard F; Meile, Leo

    2014-11-03

    Ethiopian injera, a soft pancake, baked from fermented batter, is preferentially prepared from tef (Eragrostis tef) flour. The phytic acid (PA) content of tef is high and is only partly degraded during the fermentation step. PA chelates with iron and zinc in the human digestive tract and strongly inhibits their absorption. With the aim to formulate a starter culture that would substantially degrade PA during injera preparation, we assessed the potential of microorganisms isolated from Ethiopian household-tef fermentations to degrade PA. Lactic acid bacteria (LAB) were found to be among the dominating microorganisms. Seventy-six isolates from thirteen different tef fermentations were analyzed for phytase activity and thirteen different isolates of seven different species were detected to be positive in a phytase screening assay. In 20-mL model tef fermentations, out of these thirteen isolates, the use of Lactobacillus (L.) buchneri strain MF58 and Pediococcus pentosaceus strain MF35 resulted in lowest PA contents in the fermented tef of 41% and 42%, respectively of its initial content. In comparison 59% of PA remained when spontaneously fermented. Full scale tef fermentation (0.6L) and injera production using L. buchneri MF58 as culture additive decreased PA in cooked injera from 1.05 to 0.34±0.02 g/100 g, representing a degradation of 68% compared to 42% in injera from non-inoculated traditional fermentation. The visual appearance of the pancakes was similar. The final molar ratios of PA to iron of 4 and to zinc of 12 achieved with L. buchneri MF58 were decreased by ca. 50% compared to the traditional fermentation. In conclusion, selected LAB strains in tef fermentations can degrade PA, with L. buchneri MF58 displaying the highest PA degrading potential. The 68% PA degradation achieved by the application of L. buchneri MF58 would be expected to improve human zinc absorption from tef-injera, but further PA degradation is probably necessary if iron absorption has to

  8. Potential of wine-associated lactic acid bacteria to degrade biogenic amines.

    PubMed

    García-Ruiz, Almudena; González-Rompinelli, Eva M; Bartolomé, Begoña; Moreno-Arribas, M Victoria

    2011-08-02

    Some lactic acid bacteria (LAB) isolated from fermented foods have been proven to degrade biogenic amines through the production of amine oxidase enzymes. Since little is known about this in relation to wine micro-organisms, this work examined the ability of LAB strains (n=85) isolated from wines and other related enological sources, as well as commercial malolactic starter cultures (n=3) and type strains (n=2), to degrade histamine, tyramine and putrescine. The biogenic amine-degrading ability of the strains was evaluated by RP-HPLC in culture media and wine malolactic fermentation laboratory experiments. Although at different extent, 25% of the LAB isolates were able to degrade histamine, 18% tyramine and 18% putrescine, whereas none of the commercial malolactic starter cultures or type strains were able to degrade any of the tested amines. The greatest biogenic amine-degrading ability was exhibited by 9 strains belonging to the Lactobacillus and Pediococcus groups, and most of them were able to simultaneously degrade at least two of the three studied biogenic amines. Further experiments with one of the strains that showed high biogenic amine-degrading ability (L. casei IFI-CA 52) revealed that cell-free extracts maintained this ability in comparison to the cell suspensions at pH 4.6, indicating that amine-degrading enzymes were effectively extracted from the cells and their action was optimal in the degradation of biogenic amines. In addition, it was confirmed that wine components such as ethanol (12%) and polyphenols (75 mg/L), and wine additives such as SO(2) (30 mg/L), reduced the histamine-degrading ability of L. casei IFI-CA 52 at pH 4.6 by 80%, 85% and 11%, respectively, in cell suspensions, whereas the reduction was 91%, 67% and 50%, respectively, in cell-free extracts. In spite of this adverse influence of the wine matrix, our results proved the potential of wine-associated LAB as a promising strategy to reduce biogenic amines in wine.

  9. Production of Antilisterial Bacteriocins from Lactic Acid Bacteria in Dairy-Based Media: A Comparative Study.

    PubMed

    Ünlü, Gülhan; Nielsen, Barbara; Ionita, Claudia

    2015-12-01

    One hundred and eight strains of lactic acid bacteria (LAB) were screened for bacteriocin production by the modified deferred antagonism and agar well diffusion methods. When the modified deferred antagonism method was employed, 82 LAB strains showed inhibitory action against Listeria monocytogenes v7 ½a, whereas 26 LAB strains expressed no inhibition. Only 12 LAB strains exhibited inhibitory activity when the agar well diffusion method was used, 11 of which had been previously recognized as bacteriocin production positive (Bac(+)). Lactobacillus viridescens NRRL B-1951 was determined, for the first time, to produce an inhibitory compound with a proteinaceous nature. The inhibitory activity was observed in the presence of lipase, α-chymotrypsin, and trypsin, but no inhibition zone could be detected in the presence of proteinase K, indicating the proteinaceous nature of the inhibitory compound. The inhibitory compound was active against Lact. sake ATCC 15521 and Lact. plantarum NCDO 995. Bacteriocin production by the Bac(+) LAB strains was assessed in Lactobacillus MRS Broth as well as in dairy-based media such as nonfat milk, demineralized whey powder, and cheddar cheese whey supplemented with complex nutrient sources that are rich in nitrogen. Lact. sake ATCC 15521 and L. monocytogenes CWD 1002, CWD 1092, CWD 1157, CWD 1198, and v7 ½a were used as indicators. The inhibitory activities of the bacteriocins varied depending on the indicator strains and the growth media used. The LAB indicator strains were found to be more sensitive to inhibition by bacteriocins when compared to the listerial indicator strains. Among the listerial indicators, L. monocytogenes CWD 1002 and CWD 1198 were the most sensitive strains to the bacteriocins investigated in this study. Media composition had a significant influence on bacteriocin production and activity. When compared to demineralized whey powder medium and cheddar cheese whey medium supplemented with whey protein concentrate

  10. Specific Strains of Lactic Acid Bacteria Differentially Modulate the Profile of Adipokines In Vitro

    PubMed Central

    Fabersani, Emanuel; Abeijon-Mukdsi, María Claudia; Ross, Romina; Medina, Roxana; González, Silvia; Gauffin-Cano, Paola

    2017-01-01

    Obesity induces local/systemic inflammation accompanied by increases in macrophage infiltration into adipose tissue and production of inflammatory cytokines, chemokines, and hormones. Previous studies have shown that probiotics could improve the intestinal dysbiosis induced by metabolic diseases such as obesity, diabetes, and metabolic syndrome. Microorganisms could (directly or indirectly) affect adipokine levels due to their capacity to induce translocation of several intestinal microbial antigens into systemic circulation, which could lead to metabolic endotoxemia or produce immunomodulation in different organs. The aim of the present study was to select non-inflammatory lactic acid bacteria (LAB) strains with the capacity to modulate adipokine secretion by the adipose tissue. We wish to elucidate the role of potential probiotic strains in the regulation of the cross talking between immune cells such as macrophages and adipose cells. Mouse macrophage cell line RAW 264.7 was used for evaluating the ability of 14 LAB strains to induce cytokine production. The LAB strains were chosen based on their previously studied beneficial properties in health. Then, in murine adipocyte culture and macrophage–adipocyte coculture, we determined the ability of these strains to induce cytokines and leptin secretion. Tumor necrosis factor alpha, interleukin 6 (IL-6), IL-10, monocyte chemoattractant protein-1, and leptin levels were measured in cell supernatants. We also performed the detection and quantification of leptin receptor (Ob-Rb) expression in macrophage cell lines stimulated by these LAB strains. Differential secretion profile of cytokines in macrophage cells induced by LAB strains was observed. Also, the levels of Ob-Rb expression diverged among different LAB strains. In LAB-stimulated coculture cells (adipocytes and macrophages), we observed differential production of leptin and cytokines. Furthermore, we detected lower production levels in single culture than

  11. Probiotic potential of lactic acid bacteria present in home made curd in southern India

    PubMed Central

    Balamurugan, Ramadass; Chandragunasekaran, Aarthi Sophia; Chellappan, Gowri; Rajaram, Krithika; Ramamoorthi, Gayathri; Ramakrishna, Balakrishnan S.

    2014-01-01

    Background & objectives: The human gut microbiota play a significant role in nutritional processes. The concept of probiotics has led to widespread consumption of food preparations containing probiotic microbes such as curd and yogurt. Curd prepared at home is consumed every day in most homes in southern India. In this study the home-made curd was evaluated for lactic acid bacteria (LAB) with probiotic potential. Methods: Fifteen LAB (12 lactobacilli, 1 Lactococcus, 2 Leuconostoc) and one yeast isolated from home-made curd were evaluated for resistance to acid, pepsin, pancreatin and bile salts; antimicrobial resistance; intrinsic antimicrobial activity; adherence to Caco-2 epithelial cells; ability to block pathogen adherence to Caco-2 cells; ability to inhibit interleukin (IL)-8 secretion from HT-29 epithelial cells in response to Vibrio cholerae; and ability to induce anti-inflammatory cytokine expression in THP-1 monocyte cells. Results: Lactobacillus abundance in fermenting curd peaked sharply at 12 h. Nine of the strains survived exposure to acid (pH 3.0) for at least one hour, and all strains survived in the presence of pancreatin or bile salts for 3 h. None showed haemolytic activity. All were resistant to most antimicrobials tested, but were sensitive to imipenem. Most strains inhibited the growth of Salmonella Typhimurium while five inhibited growth of V. cholerae O139. Seven strains showed adherence to Caco-2 cells ranging from 20-104 per cent of adherence of an adherent strain of Escherichia coli, but all inhibited V. cholerae adherence to Caco-2 cells by 20-100 per cent. They inhibited interleukin-8 secretion from HT-29 cells, in response to V. cholerae, by 50-80 per cent. Two strains induced IL-10 and IL-12 messenger ribonucleic acid (mRNA) expression in THP-1 cells. Interpretation & conclusions: LAB in curd had properties consistent with probiotic potential, but these were not consistent across species. LAB abundance in curd increased rapidly at 12 h

  12. Growth and Metabolism of Lactic Acid Bacteria during and after Malolactic Fermentation of Wines at Different pH

    PubMed Central

    Davis, C. R.; Wibowo, D. J.; Lee, T. H.; Fleet, G. H.

    1986-01-01

    Commercially produced red wines were adjusted to pH 3.0, 3.2, 3.5, 3.7, or 4.0 and examined during and after malolactic fermentation for growth of lactic acid bacteria and changes in the concentrations of carbohydrates, organic acids, amino acids, and acetaldehyde. With one exception, Leuconostoc oenos conducted the malolactic fermentation in all wines and was the only species to occur in wines at pH below 3.5. Malolactic fermentation by L. oenos was accompanied by degradation of malic, citric, and fumaric acids and production of lactic and acetic acids. The concentrations of arginine, histidine, and acetaldehyde also decreased at this stage, but the behavior of hexose and pentose sugars was complicated by other factors. Pediococcus parvulus conducted the malolactic fermentation in one wine containing 72 mg of total sulfur dioxide per liter. Fumaric and citric acids were not degraded during this malolactic fermentation, but hexose sugars were metabolized. P. parvulus and species of Lactobacillus grew after malolactic fermentation in wines with pH adjusted above 3.5. This growth was accompanied by the utilization of wine sugars and production of lactic and acetic acids. PMID:16347015

  13. Phenotypic and genotypic diversity of dominant lactic acid bacteria isolated from traditional yoghurts produced by tribes of Iran

    PubMed Central

    RoushanZadeh, S; Eskandari, M. H.; Shekarforoush, S. S.; Hosseini, A

    2014-01-01

    Morphological, biochemical and molecular characteristics were studied to identify dominant lactic acid bacteria (LAB), isolated from traditional yoghurts produced by tribes of Iran. From 60 yoghurt samples, a total of 137 LAB isolates were determined, in which 66 and 71 were identified as lactic acid cocci and bacilli, respectively. Biochemical tests showed the occurrence of 9.76% mesophilic homofermentative, 10.98% mesophilic hetrofermentative, 26.83% thermophilic homofermentative and 47.56% mesophilic homofermentative cocci. As for lactic acid bacilli, mesophilic facultative hetrofermentative (26%); thermophilic obligate homofermentative (56%); mesophilic obligate hetrofermentative (18%) were found. Genetically the presence of the following species were verified: E. faecium; E. faecalis; E. durans; L. lactis subsp. lactis; St. thermophilus; Lb. delbruecki subsp. bulgaricus; Lb. brevis; Lb. diolivorans; Lb. helveticus; Lb. jensenii; Lb. plantarum. 9% of the Lactobacillus isolates showed incompatible results between phenotypic and genotypic characteristics. From the cocci isolates, 38.46% showed identical results between phylogenetic characteristics. The current study constitutes the first step in the designing process of LAB starter cultures, to protect the typical organoleptic characteristics of traditional yoghurt. The results could also be used to introduce new starter cultures for commercial use. PMID:27175129

  14. Effects of the Essential Oil from Origanum vulgare L. on Survival of Pathogenic Bacteria and Starter Lactic Acid Bacteria in Semihard Cheese Broth and Slurry.

    PubMed

    de Souza, Geany Targino; de Carvalho, Rayssa Julliane; de Sousa, Jossana Pereira; Tavares, Josean Fechine; Schaffner, Donald; de Souza, Evandro Leite; Magnani, Marciane

    2016-02-01

    This study assessed the inhibitory effects of the essential oil from Origanum vulgare L. (OVEO) on Staphylococcus aureus, Listeria monocytogenes, and a mesophilic starter coculture composed of lactic acid bacteria (Lactococcus lactis subsp. lactis and L. lactis subsp. cremoris) in Brazilian coalho cheese systems. The MIC of OVEO was 2.5 μl/ml against both S. aureus and L. monocytogenes and 0.6 μl/ml against the tested starter coculture. In cheese broth containing OVEO at 0.6 μl/ml, no decrease in viable cell counts (VCC) of both pathogenic bacteria was observed, whereas the initial VCC of the starter coculture decreased approximately 1.0 log CFU/ml after 24 h of exposure at 10°C. OVEO at 1.25 and 2.5 μl/ml caused reductions of up to 2.0 and 2.5 log CFU/ml in S. aureus and L. monocytogenes, respectively, after 24 h of exposure in cheese broth. At these same concentrations, OVEO caused a greater decrease of initial VCC of the starter coculture following 4 h of exposure. Higher concentrations of OVEO were required to decrease the VCC of all target bacteria in semisolid coalho cheese slurry compared with cheese broth. The VCC of Lactococcus spp. in coalho cheese slurry containing OVEO were always lower than those of pathogenic bacteria under the same conditions. These results suggest that the concentrations of OVEO used to control pathogenic bacteria in semihard cheese should be carefully evaluated because of its inhibitory effects on the growth of starter lactic acid cultures used during the production of the product.

  15. Characterization of aerobic spore-forming bacteria associated with industrial dairy processing environments and product spoilage.

    PubMed

    Lücking, Genia; Stoeckel, Marina; Atamer, Zeynep; Hinrichs, Jörg; Ehling-Schulz, Monika

    2013-09-02

    Due to changes in the design of industrial food processing and increasing international trade, highly thermoresistant spore-forming bacteria are an emerging problem in food production. Minimally processed foods and products with extended shelf life, such as milk products, are at special risk for contamination and subsequent product damages, but information about origin and food quality related properties of highly heat-resistant spore-formers is still limited. Therefore, the aim of this study was to determine the biodiversity, heat resistance, and food quality and safety affecting characteristics of aerobic spore-formers in the dairy sector. Thus, a comprehensive panel of strains (n=467), which originated from dairy processing environments, raw materials and processed foods, was compiled. The set included isolates associated with recent food spoilage cases and product damages as well as isolates not linked to product spoilage. Identification of the isolates by means of Fourier-transform infrared spectroscopy and molecular methods revealed a large biodiversity of spore-formers, especially among the spoilage associated isolates. These could be assigned to 43 species, representing 11 genera, with Bacillus cereus s.l. and Bacillus licheniformis being predominant. A screening for isolates forming thermoresistant spores (TRS, surviving 100°C, 20 min) showed that about one third of the tested spore-formers was heat-resistant, with Bacillus subtilis and Geobacillus stearothermophilus being the prevalent species. Strains producing highly thermoresistant spores (HTRS, surviving 125°C, 30 min) were found among mesophilic as well as among thermophilic species. B. subtilis and Bacillus amyloliquefaciens were dominating the group of mesophilic HTRS, while Bacillus smithii and Geobacillus pallidus were dominating the group of thermophilic HTRS. Analysis of spoilage-related enzymes of the TRS isolates showed that mesophilic strains, belonging to the B. subtilis and B. cereus

  16. Evaluation of epidemiological studies of intestinal bacteria that affected occurrence of colorectal cancer: studies of prevention of colorectal tumors by dairy products and lactic acid bacteria.

    PubMed

    Kawano, Atsuko; Ishikawa, Hideki; Nakamura, Tomiyo; Kono, Koichi

    2010-05-01

    Enviromental factors have been consistently associated with colon cancer risk. In particular, consumption of Western-style diet including red meat is the most widely accepted etiologic risk factor. It has been reported that dietary factors change the proportion of intestinal flora, and it also affects the composition of fecal bile acids and the intestinal activity of some mutagens. In addition, it was suggested that modulating the composition of intestinal flora may reduce the occurrence of colorectal cancer. In this review, we present the clinical studies on the association between intestinal flora and the risk of colorectal cancer that have been carried out to date. The clinical studies of intestinal bacteria related to colorectal cancer risk have not shown consistent results so far, compared with the accomplishments of some basic studies. On the other hand, it was suggested in some clinical studies that lactic acid bacteria reduce the occurrence of colorectal cancer.

  17. Target identification of volatile metabolites to allow the differentiation of lactic acid bacteria by gas chromatography-ion mobility spectrometry.

    PubMed

    Gallegos, Janneth; Arce, Cristina; Jordano, Rafael; Arce, Lourdes; Medina, Luis M

    2017-04-01

    The purpose of this work was to study the potential of gas chromatography-ion mobility spectrometry (GC-IMS) to differentiate lactic acid bacteria (LAB) through target identification and fingerprints of volatile metabolites. The LAB selected were used as reference strains for their influence in the flavour of cheese. The four strains of LAB can be distinguished by the fingerprints generated by the volatile organic compounds (VOCs) emitted. 2-butanone, 2-pentanone, 2-heptanone and 3-methyl-1-butanol were identified as relevant VOCs for Lactobacillus casei and Lactobacillus paracasei subsp. paracasei. 2-Butanone and 3-methyl-1-butanol were identified in Lactococcus lactis subsp. lactis and Lactococcus cremoris subsp. cremoris. The IMS signals monitoring during a 24-30h period showed the growth of the LAB in vitro. The results demonstrated that GC-IMS is a useful technology for bacteria recognition and also for screening the aromatic potential of new isolates of LAB.

  18. Lactic acid bacteria evolution during winemaking: use of rpoB gene as a target for PCR-DGGE analysis.

    PubMed

    Renouf, Vincent; Claisse, Olivier; Miot-Sertier, Cécile; Lonvaud-Funel, Aline

    2006-04-01

    Evolution of the microbial population during winemaking is crucial. Winemakers are more and more attentive to microbial aspects during fermentation. During aging, microbial stabilization is preponderant to avoid development of spoilage yeast and bacteria. Therefore, it is necessary to improve methods to study the evolution of micro-organisms and for early detection of undesirable strain. The aim of this study was to develop a culture-independent method for identifying lactic acid bacteria (LAB) and to monitoring predominant species. The benefits of PCR-DGGE for the analysis of microbial changes during winemaking were clearly demonstrated. Targeting rpoB gene allowed a reliable discrimination of each species. The primers were able to avoid the interspecies heterogeneity problem caused by the use of the 16S rRNA gene. This method was applied to study the influence of different oenological practices on LAB population and their evolution during winemaking.

  19. A prebiotic role of Ecklonia cava improves the mortality of Edwardsiella tarda-infected zebrafish models via regulating the growth of lactic acid bacteria and pathogen bacteria.

    PubMed

    Lee, WonWoo; Oh, Jae Young; Kim, Eun-A; Kang, Nalae; Kim, Kil-Nam; Ahn, Ginnae; Jeon, You-Jin

    2016-07-01

    In this study, the beneficial prebiotic roles of Ecklonia cava (E. cava, EC) were evaluated on the growth of lactic acid bacteria (LAB) and pathogen bacteria and the mortality of pathogen-bacteria infected zebrafish model. The result showed that the original E. cava (EC) led to the highest growth effects on three LABs (Lactobacillus brevis, L. brevis; Lactobacillus pentosus, L. pentosus; Lactobacillus plantarum; L. plantarum) and it was dose-dependent manners. Also, EC, its Celluclast enzymatic (ECC) and 100% ethanol extracts (ECE) showed the anti-bacterial activities on the fish pathogenic bacteria such as (Edwardsiella tarda; E. tarda, Streptococcus iniae; S. iniae, and Vibrio harveyi; V. harveyi). Interestingly, EC induced the higher production of the secondary metabolites from L. plantarum in MRS medium. The secondary metabolites produced by EC significantly inhibited the growth of pathogen bacteria. In further in vivo study, the co-treatment of EC and L. plantarum improved the growth and mortality of E. tarda-infected zebrafish as regulating the expression of inflammatory molecules such as iNOS and COX2. Taken together, our present study suggests that the EC plays an important role as a potential prebiotic and has a protective effect against the infection caused by E. tarda injection in zebrafish. Also, our conclusion from this evidence is that EC can be used and applied as a useful prebiotic.

  20. A novel plasmid for delivering genes into mammalian cells with noninvasive food and commensal lactic acid bacteria.

    PubMed

    Tao, Lin; Pavlova, Sylvia I; Ji, Xin; Jin, Ling; Spear, Gregory

    2011-01-01

    Using food and commensal lactic acid bacteria (LAB) as vehicles for DNA delivery into epithelial cells is a new strategy for vaccine delivery or gene therapy. However, present methods for DNA delivery with LAB have suffered low efficiency. Our goal was to develop a new system to deliver DNA into epithelial cells with high efficiency using food and commensal LAB. An Escherichia coli-LAB shuttle plasmid, pLKV1, for DNA delivery into eukaryotic cells was constructed. Two reporter plasmids with green and red fluorescent protein genes were also constructed to monitor the uptake of protein and DNA, respectively. Bacteria delivering these reporter plasmids into Caco-2 cells were monitored by fluorescence microscopy. Several methods that weaken the bacterial cell wall prior to co-culture with Caco-2 cells were evaluated for their role in the improvement of gene transfer efficiency. Treating Streptococcus gordonii with penicillin and lysozyme greatly increased its rate of gene delivery to mammalian cells compared to untreated control bacteria, while glycine pretreatment promoted the highest gene transfer rate for Lactococcus lactis. Uptake of green fluorescent bacteria by Caco-2 cells showed that the cell wall-weakening treatment promoted the internalization of the noninvasive bacteria into Caco-2 cells. In conclusion, we have developed a noninvasive system using LAB as a vehicle for vaccine delivery or gene therapy, and tested this system in vitro with Caco-2 cells.

  1. Exopolysaccharides Isolated from Milk Fermented with Lactic Acid Bacteria Prevent Ultraviolet-Induced Skin Damage in Hairless Mice

    PubMed Central

    Morifuji, Masashi; Kitade, Masami; Fukasawa, Tomoyuki; Yamaji, Taketo; Ichihashi, Masamitsu

    2017-01-01

    Background: We studied the mechanism by which fermented milk ameliorates UV-B-induced skin damage and determined the active components in milk fermented with lactic acid bacteria by evaluating erythema formation, dryness, epidermal proliferation, DNA damage and cytokine mRNA levels in hairless mice exposed to acute UV-B irradiation. Methods: Nine week-old hairless mice were given fermented milk (1.3 g/kg BW/day) or exopolysaccharide (EPS) concentrate (70 mg/kg BW/day) orally for ten days. Seven days after fermented milk or EPS administration began, the dorsal skin of the mice was exposed to a single dose of UV-B (20 mJ/cm2). Results: Ingestion of either fermented milk or EPS significantly attenuated UV-B-induced erythema formation, dryness and epidermal proliferation in mouse skin. Both fermented milk and EPS were associated with a significant decrease in cyclobutane pyrimidine dimers and upregulated mRNA levels of xeroderma pigmentosum complementation group A (XPA), which is involved in DNA repair. Furthermore, administration of either fermented milk or EPS significantly suppressed increases in the ratio of interleukin (IL)-10/IL-12a and IL-10/interferon-gamma mRNA levels. Conclusion: Together, these results indicate that EPS isolated from milk fermented with lactic acid bacteria enhanced DNA repair mechanisms and modulated skin immunity to protect skin against UV damage. PMID:28098755

  2. Characterization of lactic acid bacteria isolated from infant faeces as potential probiotic starter cultures for fermented sausages.

    PubMed

    Rubio, Raquel; Jofré, Anna; Martín, Belén; Aymerich, Teresa; Garriga, Margarita

    2014-04-01

    A total of 109 lactic acid bacteria isolated from infant faeces were identified by partial 16S rRNA, cpn60 and/or pheS sequencing. Lactobacillus was the most prevalent genus, representing 48% of the isolates followed by Enterococcus (38%). Lactobacillus gasseri (21%) and Enterococcus faecalis (38%) were the main species detected. A further selection of potential probiotic starter cultures for fermented sausages focused on Lactobacillus as the most technologically relevant genus in this type of product. Lactobacilli strains were evaluated for their ability to grow in vitro in the processing conditions of fermented sausages and for their functional and safety properties, including antagonistic activity against foodborne pathogens, survival from gastrointestinal tract conditions (acidity, bile and pancreatin), tyramine production, antibiotic susceptibility and aggregation capacity. The best strains according to the results obtained were Lactobacillus casei/paracasei CTC1677, L. casei/paracasei CTC1678, Lactobacillus rhamnosus CTC1679, L. gasseri CTC1700, L. gasseri CTC1704, Lactobacillus fermentum CTC1693. Those strains were further assayed as starter cultures in model sausages. L. casei/paracasei CTC1677, L. casei/paracasei CTC1678 and L. rhamnosus CTC1679 were able to lead the fermentation and dominate (levels ca. 10(8) CFU/g) the endogenous lactic acid bacteria, confirming their suitability as probiotic starter cultures.

  3. In Situ Production of Exopolysaccharides during Sourdough Fermentation by Cereal and Intestinal Isolates of Lactic Acid Bacteria

    PubMed Central

    Tieking, Markus; Korakli, Maher; Ehrmann, Matthias A.; Gänzle, Michael G.; Vogel, Rudi F.

    2003-01-01

    EPS formed by lactobacilli in situ during sourdough fermentation may replace hydrocolloids currently used as texturizing, antistaling, or prebiotic additives in bread production. In this study, a screening of >100 strains of cereal-associated and intestinal lactic acid bacteria was performed for the production of exopolysaccharides (EPS) from sucrose. Fifteen strains produced fructan, and four strains produced glucan. It was remarkable that formation of glucan and fructan was most frequently found in intestinal isolates and strains of the species Lactobacillus reuteri, Lactobacillus pontis, and Lactobacillus frumenti from type II sourdoughs. By the use of PCR primers derived from conserved amino acid sequences of bacterial levansucrase genes, it was shown that 6 of the 15 fructan-producing lactobacilli and none of 20 glucan producers or EPS-negative strains carried a levansucrase gene. In sourdough fermentations, it was determined whether those strains producing EPS in MRS medium modified as described by Stolz et al. (37) and containing 100 g of sucrose liter−1 as the sole source of carbon also produce the same EPS from sucrose during sourdough fermentation in the presence of 12% sucrose. For all six EPS-producing strains evaluated in sourdough fermentations, in situ production of EPS at levels ranging from 0.5 to 2 g/kg of flour was demonstrated. Production of EPS from sucrose is a metabolic activity that is widespread among sourdough lactic acid bacteria. Thus, the use of these organisms in bread production may allow the replacement of additives. PMID:12571016

  4. Nondairy beverage produced by controlled fermentation with potential probiotic starter cultures of lactic acid bacteria and yeast.

    PubMed

    Freire, Ana Luiza; Ramos, Cintia Lacerda; da Costa Souza, Patrícia Nirlane; Cardoso, Mauro Guilherme Barros; Schwan, Rosane Freitas

    2017-02-21

    This work aimed to develop a nondairy fermented beverage from a blend of cassava and rice based on Brazilian indigenous beverage cauim using probiotic lactic acid bacteria (LAB) and yeast. The indigenous strains Lactobacillus plantarum CCMA 0743 (from cauim) and Torulaspora delbrueckii CCMA 0235 (from tarubá), and the commercial probiotic, L. acidophilus LAC-04, were used as starter cultures in single and co-cultivations. The bacteria populations were around 8.0 log (CFU/mL) at the end of all fermentations as recommended for probiotic products. Higher residual starch contents were noted in the single LAB cultures (10.6% [w/w]) than in co-cultures (<6% [w/w]), showing that co-culture may help the digestibility. For all different assays (single and co-culture), lactic acid was the main organic acid detected (>1.6g/L) and ethanol was lower than 0.5% (w/v) consisting in a non-alcoholic beverage. The assays containing yeast showed the highest antioxidant activity (around 10% by DPPH and ABTS methods). Therefore, a nondairy fermented beverage was successfully obtained, and the co-culture of LAB and T. delbrueckii could increase the product's functional properties.

  5. Multiparametric flow cytometry allows rapid assessment and comparison of lactic acid bacteria viability after freezing and during frozen storage.

    PubMed

    Rault, Aline; Béal, Catherine; Ghorbal, Sarrah; Ogier, Jean-Claude; Bouix, Marielle

    2007-08-01

    Freezing is widely used for the long-term preservation of lactic acid bacteria, but often affects their viability and technological properties. Different methods are currently employed to determine bacterial cryotolerance, but they all require several hours or days before achieving results. The aim of this study was to establish the advantages of multiparametric flow cytometry by using two specific fluorescent probes to provide rapid assessment of the viability of four strains of Lactobacillus delbrueckii after freezing and during frozen storage. The relevance of carboxyfluorescein diacetate and propidium iodide to quantify bacterial viability was proven. When bacterial suspensions were simultaneously stained with these two fluorescent probes, three major subpopulations were identified: viable, dead and injured cells. The cryotolerance of four L. delbrueckii strains was evaluated by quantifying the relative percentages of each subpopulation before and after freezing, and throughout one month of storage at -80 degrees C. Results displayed significant differences in the resistance to freezing and frozen storage of the four strains when they were submitted to the same freezing and storage procedures. Whereas resistant strains displayed less than 10% of dead cells after one month of storage, one sensitive strain exhibited more than 50% of dead cells, together with 14% of stressed cells after freezing. Finally, this study proved that multiparametric flow cytometry was a convenient and rapid tool to evaluate the viability of lactic acid bacteria, and was well correlated with plate count results. Moreover, it made it possible to differentiate strains according to their susceptibility to freezing and frozen storage.

  6. Comparison between rinse and crush-and-rub sampling for aerobic bacteria recovery from broiler hatching eggs after sanitization.

    PubMed

    Spickler, J L; Buhr, R J; Cox, N A; Bourassa, D V; Rigsby, L L

    2011-07-01

    This study compared surface and deep eggshell aerobic bacteria recovered by the rinse and crush-and-rub sampling methods for commercial hatching eggs after treatment with sanitizers. Eggs were arranged into 5 treatments consisting of no treatment, water, and 3 sanitizers. The sanitizers were H(2)O(2), phenol, and Q(4)B (a compound chemical containing 4 quaternary ammoniums and 1 biguanide moiety). Eggs were sprayed according to treatment and allowed to dry for 1 h before sampling. To collect samples for the eggshell rinse, each egg was massaged in a plastic bag with 20 mL of saline. Eggshells were then aseptically opened and their contents were discarded before being individually crushed into 50-mL centrifuge tubes containing 20 mL of saline. Aerobic bacteria were enumerated on Petrifilm after 48 h of incubation at 37°C. Aerobic bacteria recovered (log(10) cfu/mL) from the eggshell rinse were highest and similar for the no-treatment (4.0) and water (3.7) groups, lower for the phenol (3.2) and H(2)O(2) (3.1) groups, and lowest for the Q(4)B (2.4) group. Aerobic bacteria levels with the crush-and-rub method were similar for the no-treatment (2.5) and water (2.3) groups, lower for the phenol (1.6) group, intermediate for the H(2)O(2) (1.2) group, and lowest for the Q(4)B (0.9) group. The overall correlation between the rinse and crush-and-rub sampling methods for individual egg aerobic bacteria counts was r = 0.71. The correlation within each treatment revealed the following r values: no treatment, 0.55; water, 0.72; H(2)O(2), 0.67; phenol, 0.73; and Q(4)B, 0.38. A second experiment was designed to further examine the lower aerobic bacterial levels recovered by the crush-and-rub method (for previously rinsed eggs) than the levels recovered in the initial eggshell rinse sample. Eggs were either rinsed and then crushed and rubbed, or they were only crushed and rubbed without a prior rinse. Results confirmed a significant decrease (1.5 log(10) cfu/mL) in bacteria levels

  7. Dynamics of phosphorus and phytate-utilizing bacteria during aerobic degradation of dairy cattle dung.

    PubMed

    Fuentes, Bárbara; Jorquera, Milko; Mora, María de la Luz

    2009-01-01

    During organic wastes degradation, P is transformed which may affect its availability. In this study, the dynamics of P and the occurrence of phytate-utilizing bacteria (PUB) were evaluated during aerobic degradation of dairy cattle dung in laboratory-scale reactors for 105 d. The results showed an increase of water-soluble inorganic P (Pi) (from 570 to 1890 mg kg(-1)) and biomass P (from 390 to 870 mg kg(-1)) during the initial 40 d. After this period, water-soluble Pi remained constant (around 1500 mg kg(-1)) and biomass P decreased (around 220 mg kg(-1)) probably due to the decrease of easily available C in dung. Under the acidic conditions in the first 20 d there was an increase in concentration of Al (25 mg kg(-1)) and Fe (27 mg kg(-1)) ions. These ions were no longer detectable in the alkaline conditions occurring after 40 d. In the same period, the Ca concentration increased (from 1170 to 2370 mg kg(-1)) and chemical speciation revealed permanent association of Ca ions with Pi. Sequential P fractionation showed a decrease of organic P in NaHCO(3), NaOH and HCl fractions and an increase of residual P (25-52% with respect to total P). Analysis by (31)P NMR also showed a decrease (from 14% to 1.6%) of phytic acid content during final experimental period (60 and 105 d). The bacteriological analysis revealed various PUB involved in degradation of the dung. Two morphotypes, genetically characterized as Enterobacter and Rahnella, which were dominant under higher content of residual P, showed strong utilization of phytate in vitro.

  8. Aerobic spore-forming bacteria for assessing quality of drinking water produced from surface water.

    PubMed

    Mazoua, Stephane; Chauveheid, Eric

    2005-12-01

    Cryptosporidium and Giardia represent a major microbiological issue for drinking water production from surface water. As their monitoring through a treatment process is rather tedious and as low-concentration goals should be reached for drinking water, aerobic spore-forming bacteria (ASFB) have been studied as an indicator microorganism for a drinking water treatment plant using surface water. The results reveal that monitoring naturally occurring ASFB better highlights daily achievable performances and identifies unusual process events for global disinfection, for both physical and chemical treatment steps in a multi-barrier drinking water treatment plant. Advantages of ASFB over usual process parameters are that these microorganisms are more sensitive to process fluctuations. The use of ASFB also showed that the efficiency of ozone disinfection is not as significantly influenced by the water temperature as reported, despite similar or higher CT values applied during warmer periods. Thus, the disinfection of resistant microorganisms with ozone can also be an efficient process at lower water temperature. ASFB have been shown to be a conservative indicator for Cryptosporidium and Giardia up to a 1st stage filtration and the ASFB Log removals can be used to estimate Log removals for Cryptosporidium and Giardia: compared to ASFB, the Log removals for Cryptosporidium or Giardia are at least equal or 50% higher, respectively. Thus, the monitoring of ASFB along a drinking water treatment process could be a useful tool for performing risk analysis for parasites such as Cryptosporidium and Giardia, and would further allow integration of daily variability into a risk analysis.

  9. Organic osmolytes in aerobic bacteria from Mono Lake, an alkaline, moderately hypersaline environment

    SciTech Connect

    Ciulla, R.A.; Roberts, M.F.; Diaz, M.R.; Taylor, B.F.

    1997-01-01

    The identity and concentrations of intracellular organic solutes were determined by nuclear magnetic resonance spectroscopy for two strains of aerobic, gram-negative bacteria isolated from Mono Lake, California, an alkaline, moderately hypersaline lake. Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) was the major endogenous solute in both organisms. Concentrations of ectoine varied with external NaCl levels in strain ML-D but not in strain ML-G, where the level was high but invariant from 1.5 to 3.0 M NaCl. Hydroxyectoine also occurred in strain ML-D, especially at elevated NaCl concentrations (2.5 and 3.0 M), but at levels lower than those of ectoine. Exogenous organic solutes that might occur in Mono Lake were examined for their effects on the de novo synthesis of ectoine. Dimethylsulfoniopropionate (DMSP) (0.1 or 1 mM) did not significantly lower ectoine levels in either isolate, and only strain ML-G showed any capacity for DMSP accumulation. With nitrogen limitation, however, DMSP (0.1 mM) substituted for ectoine in strain ML-G showed any capacity for DMSP accumulation. With nitrogen limitation, however, DMSP (0.1 mM) substituted for ectoine in strain ML-G and became the main organic solute. Glycine betaine (GB) was more effective than DMSP in affecting ectoine levels, principally in strain ML-D. Strain ML-D accumulated GB to 50 or 67% of its organic solute pool at 2.5 M NaCl, at an external level of 0.1 or 1 mM GB, respectively. Strain ML-D also accumulated arsenobetaine. The methylated zwitterionic compounds, probably metabolic products of phytoplankton (DMSP and GB) or brine shrimps (arsenobetaine) in Mono Lake, may function as osmolytes for indigenous bacteria when present at high concentrations or under conditions of nitrogen limitation or salt stress. 33 refs., 5 figs., 2 tabs.

  10. Distribution of D-amino acids in vinegars and involvement of lactic acid bacteria in the production of D-amino acids.

    PubMed

    Mutaguchi, Yuta; Ohmori, Taketo; Akano, Hirofumi; Doi, Katsumi; Ohshima, Toshihisa

    2013-01-01

    Levels of free D-amino acids were compared in 11 vinegars produced from different sources or through different manufacturing processes. To analyze the D- and L-amino acids, the enantiomers were initially converted into diastereomers using pre-column derivatization with o-phthaldialdehyde plus N-acethyl-L-cysteine or N-tert-butyloxycarbonyl-L-cysteine. This was followed by separation of the resultant fluorescent isoindol derivatives on an octadecylsilyl stationary phase using ultra-performance liquid chromatography. The analyses showed that the total D-amino acid level in lactic fermented tomato vinegar was very high. Furthermore, analysis of the amino acids in tomato juice samples collected after alcoholic, lactic and acetic fermentation during the production of lactic fermented tomato vinegar showed clearly that lactic fermentation is responsible for the D-amino acids production; marked increases in D-amino acids were seen during lactic fermentation, but not during alcoholic or acetic fermentation. This suggests lactic acid bacteria have a greater ability to produce D-amino acids than yeast or acetic acid bacteria.

  11. A study on the prevention of salmonella infection by using the aggregation characteristics of lactic Acid bacteria.

    PubMed

    Kim, Min-Soo; Yoon, Yeo-Sang; Seo, Jae-Gu; Lee, Hyun-Gi; Chung, Myung-Jun; Yum, Do-Young

    2013-06-01

    Salmonella is one of the major pathogenic bacteria that cause food poisoning. This study investigated whether heat-killed as well as live Lactobacillus protects host animal against Salmonella infection. Live and heat-killed Lactobacillusacidophilus was administered orally to Sprague-Dawley rats for 2 weeks before the rats were inoculated with Salmonella. Rise in body temperature was moderate in the group that was treated with heat-killed bacteria as compared to the Salmonella control group. The mean amount of feed intake and water consumption of each rat in the heat-killed bacteria group were nearly normal. The number of fecal Salmonellae was comparable between the live and the heat-killed L. acidophilus groups. This finding shows that L. acidophilus facilitates the excretion of Salmonella. Moreover, the levels of pro inflammatory cytokines, including tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta, in the heat-killed L. acidophilus group were significantly lower when compared to the levels in the Salmonella control group. These results indicate that nonviable lactic acid bacteria also could play an important role in preventing infections by enteric pathogens such as Salmonella.

  12. Preferential Use of Carbon Sources in Culturable Aerobic Mesophilic Bacteria of Coptotermes curvignathus's (Isoptera: Rhinotermitidae) Gut and Its Foraging Area.

    PubMed

    Wong, W Z; H'ng, P S; Chin, K L; Sajap, Ahmad Said; Tan, G H; Paridah, M T; Othman, Soni; Chai, E W; Go, W Z

    2015-10-01

    The lower termite, Coptotermes curvignathus, is one of the most prominent plantation pests that feed upon, digest, and receive nourishment from exclusive lignocellulose diets. The objective of this study was to examine the utilization of sole carbon sources by isolated culturable aerobic bacteria among communities from the gut and foraging pathway of C. curvignathus. We study the bacteria occurrence from the gut of C. curvignathus and its surrounding feeding area by comparing the obtained phenotypic fingerprint with Biolog's extensive species library. A total of 24 bacteria have been identified mainly from the family Enterobacteriaceae from the identification of Biolog Gen III. Overall, the bacteria species in the termite gut differ from those of foraging pathway within a location, except Acintobacter baumannii, which was the only bacteria species found in both habitats. Although termites from a different study area do not have the same species of bacteria in the gut, they do have a bacterial community with similar role in degrading certain carbon sources. Sugars were preferential in termite gut isolates, while nitrogen carbon sources were preferential in foraging pathway isolates. The preferential use of specific carbon sources by these two bacterial communities reflects the role of bacteria for regulation of carbon metabolism in the termite gut and foraging pathway.

  13. Application of Impedance Microbiology for Evaluating Potential Acidifying Performances of Starter Lactic Acid Bacteria to Employ in Milk Transformation.

    PubMed

    Bancalari, Elena; Bernini, Valentina; Bottari, Benedetta; Neviani, Erasmo; Gatti, Monica

    2016-01-01

    Impedance microbiology is a method that enables tracing microbial growth by measuring the change in the electrical conductivity. Different systems, able to perform this measurement, are available in commerce and are commonly used for food control analysis by mean of measuring a point of the impedance curve, defined "time of detection." With this work we wanted to find an objective way to interpret the metabolic significance of impedance curves and propose it as a valid approach to evaluate the potential acidifying performances of starter lactic acid bacteria to be employed in milk transformation. To do this it was firstly investigated the possibility to use the Gompertz equation to describe the data coming from the impedance curve obtained by mean of BacTrac 4300®. Lag time (λ), maximum specific M% rate (μmax), and maximum value of M% (Yend) have been calculated and, given the similarity of the impedance fitted curve to the bacterial growth curve, their meaning has been interpreted. Potential acidifying performances of eighty strains belonging to Lactobacillus helveticus, Lactobacillus delbrueckii subsp. bulgaricus, Lactococcus lactis, and Streptococcus thermophilus species have been evaluated by using the kinetics parameters, obtained from Excel add-in DMFit version 2.1. The novelty and importance of our findings, obtained by means of BacTrac 4300®, is that they can also be applied to data obtained from other devices. Moreover, the meaning of λ, μmax, and Yend that we have extrapolated from Modified Gompertz equation and discussed for lactic acid bacteria in milk, can be exploited also to other food environment or other bacteria, assuming that they can give a curve and that curve is properly fitted with Gompertz equation.

  14. Selection of lactic acid bacteria from Brazilian kefir grains for potential use as starter or probiotic cultures.

    PubMed

    Zanirati, Débora Ferreira; Abatemarco, Mário; Sandes, Sávio Henrique de Cicco; Nicoli, Jacques Robert; Nunes, Álvaro Cantini; Neumann, Elisabeth

    2015-04-01

    Brazilian kefir is a homemade fermented beverage that is obtained by incubating milk or a brown sugar solution with kefir grains that contribute their different microbiological compositions. It is highly important to isolate and characterize microorganisms from Brazilian kefir grains to obtain starter cultures for the industrial production of a standardized commercial kefir. Thus, the present study aimed to isolate lactic acid bacteria from eight kefir grains that were propagated in milk or sugar solutions from five different locations in Brazil and to select Lactobacillus isolates based on desirable in vitro probiotic properties. One hundred eight isolates from both substrates were identified by amplified ribosomal DNA restriction analysis and/or 16S rRNA gene sequencing and were determined to belong to the following 11 species from the genera: Lactococcus, Leuconostoc, Lactobacillus (L.), and Oenococcus. Leuconostoc mesenteroides, Lactobacillus kefiri, and Lactobacillus kefiranofaciens were isolated only from milk grains, whereas Lactobacillus perolens, Lactobacillus parafarraginis, Lactobacillus diolivorans, and Oenococcus oeni were isolated exclusively from sugar water grains. When the microbial compositions of four kefir grains were evaluated with culture-independent analyses, L. kefiranofaciens was observed to predominant in milk grains, whereas Lactobacillus hilgardii was most abundant in sugar water kefir. Unfortunately, L. hilgardii was not isolated from any grain, although this bacteria was detected with a culture-independent methodology. Fifty-two isolated Lactobacilli were tested for gastric juice and bile salt tolerance, antagonism against pathogens, antimicrobial resistance, and surface hydrophobicity. Three Lactobacillus strains (L. kefiranofaciens 8U, L. diolivorans 1Z, and Lactobacillus casei 17U) could be classified as potential probiotics. In conclusion, several lactic acid bacteria that could be used in combination with yeasts as starter

  15. Application of Impedance Microbiology for Evaluating Potential Acidifying Performances of Starter Lactic Acid Bacteria to Employ in Milk Transformation

    PubMed Central

    Bancalari, Elena; Bernini, Valentina; Bottari, Benedetta; Neviani, Erasmo; Gatti, Monica

    2016-01-01

    Impedance microbiology is a method that enables tracing microbial growth by measuring the change in the electrical conductivity. Different systems, able to perform this measurement, are available in commerce and are commonly used for food control analysis by mean of measuring a point of the impedance curve, defined “time of detection.” With this work we wanted to find an objective way to interpret the metabolic significance of impedance curves and propose it as a valid approach to evaluate the potential acidifying performances of starter lactic acid bacteria to be employed in milk transformation. To do this it was firstly investigated the possibility to use the Gompertz equation to describe the data coming from the impedance curve obtained by mean of BacTrac 4300®. Lag time (λ), maximum specific M% rate (μmax), and maximum value of M% (Yend) have been calculated and, given the similarity of the impedance fitted curve to the bacterial growth curve, their meaning has been interpreted. Potential acidifying performances of eighty strains belonging to Lactobacillus helveticus, Lactobacillus delbrueckii subsp. bulgaricus, Lactococcus lactis, and Streptococcus thermophilus species have been evaluated by using the kinetics parameters, obtained from Excel add-in DMFit version 2.1. The novelty and importance of our findings, obtained by means of BacTrac 4300®, is that they can also be applied to data obtained from other devices. Moreover, the meaning of λ, μmax, and Yend that we have extrapolated from Modified Gompertz equation and discussed for lactic acid bacteria in milk, can be exploited also to other food environment or other bacteria, assuming that they can give a curve and that curve is properly fitted with Gompertz equation. PMID:27799925

  16. Phylogenetic group- and species-specific oligonucleotide probes for single-cell detection of lactic acid bacteria in oral biofilms

    PubMed Central

    2011-01-01

    Background The purpose of this study was to design and evaluate fluorescent in situ hybridization (FISH) probes for the single-cell detection and enumeration of lactic acid bacteria, in particular organisms belonging to the major phylogenetic groups and species of oral lactobacilli and to Abiotrophia/Granulicatella. Results As lactobacilli are known for notorious resistance to probe penetration, probe-specific assay protocols were experimentally developed to provide maximum cell wall permeability, probe accessibility, hybridization stringency, and fluorescence intensity. The new assays were then applied in a pilot study to three biofilm samples harvested from variably demineralized bovine enamel discs that had been carried in situ for 10 days by different volunteers. Best probe penetration and fluorescent labeling of reference strains were obtained after combined lysozyme and achromopeptidase treatment followed by exposure to lipase. Hybridization stringency had to be established strictly for each probe. Thereafter all probes showed the expected specificity with reference strains and labeled the anticipated morphotypes in dental plaques. Applied to in situ grown biofilms the set of probes detected only Lactobacillus fermentum and bacteria of the Lactobacillus casei group. The most cariogenic biofilm contained two orders of magnitude higher L. fermentum cell numbers than the other biofilms. Abiotrophia/Granulicatella and streptococci from the mitis group were found in all samples at high levels, whereas Streptococcus mutans was detected in only one sample in very low numbers. Conclusions Application of these new group- and species-specific FISH probes to oral biofilm-forming lactic acid bacteria will allow a clearer understanding of the supragingival biome, its spatial architecture and of structure-function relationships implicated during plaque homeostasis and caries development. The probes should prove of value far beyond the field of oral microbiology, as many of

  17. Diversity of lactic acid bacteria from modified atmosphere packaged sliced cooked meat products at sell-by date assessed by PCR-denaturing gradient gel electrophoresis.

    PubMed

    Audenaert, Kris; D'Haene, Klaas; Messens, Kathy; Ruyssen, Tony; Vandamme, Peter; Huys, Geert

    2010-02-01

    The predominant lactic acid bacteria (LAB) microbiota associated with three types of modified atmosphere packaged (MAP) sliced cooked meat products (i.e. ham, turkey and chicken) was analyzed at sell-by date using a combination of culturing and molecular population fingerprinting. Likewise routine analyses during industrial MAP production, meat samples were plated on the general heterotrophic Plate Count Agar (PCA) and on the LAB-specific de Man, Rogosa, Sharpe (MRS) agar under different temperature and atmosphere conditions. Subsequently, community DNA extracts were prepared from culturable bacterial fractions harvested from both media and used for PCR targeting the V3 hyper-variable region of the 16S rRNA gene followed by denaturing gradient gel electrophoresis (DGGE) of PCR amplicons (PCR-DGGE). Irrespective of aerobic or anaerobic incubation conditions, V3-16S rDNA DGGE fingerprints of culturable fractions from PCA and MRS medium displayed a high level of similarity indicating that LAB constituted the most dominant group in the culturable bacterial community. Comparison of DGGE profiles of fractions grown at 20, 28 or 37 degrees C indicated that part of the culturable community consisted of psychrotrophs. Four DGGE bands were common among cooked ham, turkey and chicken products, suggesting that these represent the microbiota circulating in the plant where all three MAP product types were sliced and packaged. Based on band sequencing and band position analysis using LAB reference strains, these four bands could be assigned to Lactobacillus sakei and/or the closely related Lactobacillus fuchuensis, Lactobacillus curvatus, Carnobacterium divergens and Leuconostoc carnosum. In conclusion, the PCR-DGGE approach described in this study allows to discriminate, identify and monitor core and occasional LAB microbiota of MAP sliced cooked meat products and provides valuable complementary information to the current plating procedures routinely used in industrial plants.

  18. Effectiveness of Active Packaging on Control of Escherichia Coli O157:H7 and Total Aerobic Bacteria on Iceberg Lettuce.

    PubMed

    Lu, Haixia; Zhu, Junli; Li, Jianrong; Chen, Jinru

    2015-06-01

    Contaminated leafy green vegetables have been linked to several outbreaks of human gastrointestinal infections. Antimicrobial interventions that are adoptable by the fresh produce industry for control of pathogen contamination are in great demand. This study was undertaken to evaluate the efficacy of sustained active packaging on control of Escherichia coli O157:H7 and total aerobic bacteria on lettuce. Commercial Iceberg lettuce was inoculated with a 3-strain mixture of E. coli O157:H7 at 10(2) or 10(4) CFU/g. The contaminated lettuce and un-inoculated controls were placed respectively in 5 different active packaging structures. Traditional, nonactive packaging structure was included as controls. Packaged lettuce was stored at 4, 10, or 22 °C for 3 wk and sampled weekly for the population of E. coli O157:H7 and total aerobic bacteria. Results showed that packaging structures with ClO2 generator, CO2 generator, or one of the O2 scavengers effectively controlled the growth of E. coli O157:H7 and total aerobic bacteria under all storage conditions. Packaging structure with the ClO2 generator was most effective and no E. coli O157:H7 was detected in samples packaged in this structure except for those that were inoculated with 4 log CFU/g of E. coli O157:H7 and stored at 22 °C. Packaging structures with an oxygen scavenger and the allyl isothiocyanate generator were mostly ineffective in control of the growth of the bacteria on Iceberg lettuce. The research suggests that some of the packaging structures evaluated in the study can be used to control the presence of foodborne pathogens on leafy green vegetables.

  19. Determinative factors of competitive advantage between aerobic bacteria for niches at the air-liquid interface.

    PubMed

    Yamamoto, Kyosuke; Haruta, Shin; Kato, Souichiro; Ishii, Masaharu; Igarashi, Yasuo

    2010-01-01

    We focused on bacterial interspecies relationships at the air-liquid interface where the formation of pellicles by aerobes was observed. Although an obligate aerobe (Brevibacillus sp. M1-5) was initially dominant in the pellicle population, a facultative aerobe (Pseudoxanthomonas sp. M1-3) emerged and the viability of M1-5 rapidly decreased due to severe competition for oxygen. Supplementation of the medium with carbohydrates allowed the two species to coexist at the air-liquid interface. These results indicate that the population dynamics within pellicles are primarily governed by oxygen utilization which was affected by a combination of carbon sources.

  20. Identification of lactic acid bacteria in the rumen and feces of dairy cows fed total mixed ration silage to assess the survival of silage bacteria in the gut.

    PubMed

    Han, H; Ogata, Y; Yamamoto, Y; Nagao, S; Nishino, N

    2014-09-01

    The survival of silage lactic acid bacteria (LAB) in the gut of dairy cows was evaluated by examining the LAB communities of silage and gut contents. Samples were collected at 2 different research institutes (Mie and Okayama) that offered total mixed ration (TMR) silage throughout the year. Silage and feces were sampled in August, October, and November at the Mie institute, whereas silage, rumen fluid, and feces were sampled in June and August at the Okayama institute. Denaturing gradient gel electrophoresis using Lactobacillus-specific primers was performed to detect LAB species in the samples. The selected bands were purified for species identification and the band patterns were used for principal component analysis. Lactic acid was the predominant fermentation product in all the TMR silages analyzed, and the lactic acid level tended to be constant regardless of the sampling time and region. A total of 14 LAB species were detected in the TMR silage samples, of which 5 (Lactobacillus acetotolerans, Lactobacillus pontis, Lactobacillus casei, Lactobacillus suebicus, and Lactobacillus plantarum) were detected in the dairy cow feces. Most of the denaturing gradient gel electrophoresis bands for the feces samples were also detected in the rumen fluid, suggesting that any elimination of silage LAB occurred in the rumen and not in the postruminal gut segments. The principal component analysis indicated that the LAB communities in the silage, rumen fluid, and feces were separately grouped; hence, the survival of silage LAB in the cow rumen and lower gut was deemed difficult. It was concluded that, although the gut LAB community is robust and not easily affected by the silage conditions, several LAB species can inhabit both silage and feces, which suggests the potential of using silage as a vehicle for conveying probiotics.

  1. Biodiversity of lactic acid bacteria in French wheat sourdough as determined by molecular characterization using species-specific PCR.

    PubMed

    Robert, Hervé; Gabriel, Valérie; Fontagné-Faucher, Catherine

    2009-09-30

    The lactic acid microflora of nine traditional wheat sourdoughs from the Midi-Pyrénées area (South western France) was previously isolated and preliminary characterized using conventional morphological and biochemical analysis. However, such phenotypic methods alone are not always reliable and have a low taxonomic resolution for identification of lactic acid bacteria species. In the present study, a total of 290 LAB isolates were identified by PCR amplification using different sets of specific primers in order to provide a thorough characterization of the lactic flora from these traditional French sourdoughs. Overall, the LAB isolates belonged to 6 genera: Lactobacillus (39%, 8 species), Pediococcus (38%, 1 species), Leuconostoc (17%, 2 species), Weissella (4%, 2 species), Lactococcus (1%, 1 species) and Enterococcus (<1%, 1 species) and 15 different species were detected: L. plantarum, L. curvatus, L. paracasei, L. sanfranciscensis, L. pentosus, L. paraplantarum, L. sakei, L. brevis, P. pentosaceus, L. mesenteroides, L. citreum, W. cibaria, W. confusa, L. lactis and E. hirae. Facultative heterofermentative LAB represent more than 76% of the total isolates, the main species isolated herein correspond to L. plantarum and P. pentosaceus. Obligate heterofermentative lactobacilli (L. sanfranciscencis, L. brevis) represent less than 3% of the total isolates whereas Leuconostoc and Weissella species represent 21% of the total isolates and have been detected in eight of the nine samples. Detection of some LAB species was preferentially observed depending on the isolation culture medium. The number of different species within a sourdough varies from 3 to 7 and original associations of hetero- and homofermentative LAB species have been revealed. Results from this study clearly confirm the diversity encountered in the microbial community of traditional sourdough and highlight the importance of LAB cocci in the sourdough ecosystem, along with lactobacilli.

  2. Identification, stress tolerance, and antioxidant activity of lactic acid bacteria isolated from tropically grown fruits and leaves.

    PubMed

    Fessard, Amandine; Bourdon, Emmanuel; Payet, Bertrand; Remize, Fabienne

    2016-07-01

    From 6 samples of tropically grown fruits and leaves, 10 lactic acid bacteria belonging Leuconostoc, Weissella, and Lactobacillus species were isolated and identified by 16S rRNA gene sequencing and (GTG)5 fingerprinting. Acidification kinetics determined from BHI broth cultures showed genus-related patterns. In particular, Weissella cibaria appeared to act as a potent acidifier. Tolerance of isolates to acid, oxidative, or salt stress was highly variable and strain dependent. Isolate S14 (Leuconostoc pseudomesenteroides) growth was not affected by the presence of 0.05% H2O2, while Lactobacillus spp. isolates (S17 and S29) were the most tolerant to pH 4.5. The growth of 4 isolates, S5 (Leuconostoc mesenteroides), S14 and S10 (Leuconostoc pseudomesenteroides), and S27 (W. cibaria), was not affected by 5% NaCl. Nutritional beneficial properties were examined through measurement of antioxidant activities of short-term fermented pineapple juice, such as LDL oxidation and polyphenol content, and through exopolysaccharide formation from sucrose. Two isolates, S14 and S27, increased the antioxidant capacity of pineapple juice. The robust capacity of W. cibaria and of Leuconostoc pseudomesenteroides for vegetable lactic fermentation aimed to ameliorate food nutritional and functional quality was highlighted.

  3. Identification of lactic acid bacteria constituting the predominating microflora in an acid-fermented condiment (tempoyak) popular in Malaysia.

    PubMed

    Leisner, J J; Vancanneyt, M; Rusul, G; Pot, B; Lefebvre, K; Fresi, A; Tee, L K

    2001-01-22

    Tempoyak is a traditional Malaysian fermented condiment made from the pulp of the durian fruit (Durio zibethinus). Salt is sometime added to proceed fermentation at ambient temperature. In various samples obtained from night markets, lactic acid bacteria (LAB) were the predominant microorganisms, ranging from log 8.4 to log 9.2 cfu g(-1). No other microorganisms were present to such a level. These samples contained reduced amount of saccharose, glucose and fructose but increased amount of D- and L-lactic acid and acetic acid compared with samples of non-fermented durian fruit. Sixty-four isolates of LAB were divided into five groups by use of a few phenotypic tests. A total of 38 strains of LAB were selected for comparison by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of their whole cell protein patterns with a SDS-PAGE database of LAB. These strains were also examined for their carbohydrate fermentation patterns by use of API 50 CH. Isolates belonging to the Lactobacillus plantarum group were shown to be the predominant members of the LAB flora. In addition, isolates belonging to the Lactobacillus brevis group, Leuconostoc mesenteroides, Lactobacillus mali, Lactobacilus fermentum and an unidentified Lactobacillus sp. were also observed. A high degree of diversity among isolates belonging to the Lb. plantarum group was demonstrated by analysis of their plasmid profiles.

  4. Production of Functional High-protein Beverage Fermented with Lactic Acid Bacteria Isolated from Korean Traditional Fermented Food.

    PubMed

    Cho, Young-Hee; Shin, Il-Seung; Hong, Sung-Moon; Kim, Cheol-Hyun

    2015-01-01

    The aim of this study was to manufacture functional high protein fermented beverage, using whey protein concentrate (WPC) and Lactobacillus plantarum DK211 isolated from kimchi, and to evaluate the physicochemical, functional, and sensory properties of the resulting product. The fermented whey beverage (FWB) was formulated with whey protein concentrate 80 (WPC 80), skim milk powder, and sucrose; and fermented with Lactobacillus plantarum DK211 as single, or mixed with Lactococcus lactis R704, a commercial starter culture. The pH, titratable acidity, and viable cell counts during fermentation and storage were evaluated. It was found that the mixed culture showed faster acid development than the single culture. The resulting FWB had high protein (9%) and low fat content (0.2%). Increased viscosity, and antioxidant and antimicrobial activity were observed after fermentation. A viable cell count of 10(9) CFU/mL in FWB was achieved within 10 h fermentation, and it remained throughout storage at 15℃ for 28 d. Sensory analysis was also conducted, and compared to that of a commercial protein drink. The sensory scores of FWB were similar to those of the commercial protein drink in most attributes, except sourness. The sourness was highly related with the high lactic acid content produced during fermentation. The results showed that WPC and vegetable origin lactic acid bacteria isolated from kimchi might be used for the development of a high protein fermented beverage, with improved functionality and organoleptic properties.

  5. Production of Functional High-protein Beverage Fermented with Lactic Acid Bacteria Isolated from Korean Traditional Fermented Food

    PubMed Central

    2015-01-01

    The aim of this study was to manufacture functional high protein fermented beverage, using whey protein concentrate (WPC) and Lactobacillus plantarum DK211 isolated from kimchi, and to evaluate the physicochemical, functional, and sensory properties of the resulting product. The fermented whey beverage (FWB) was formulated with whey protein concentrate 80 (WPC 80), skim milk powder, and sucrose; and fermented with Lactobacillus plantarum DK211 as single, or mixed with Lactococcus lactis R704, a commercial starter culture. The pH, titratable acidity, and viable cell counts during fermentation and storage were evaluated. It was found that the mixed culture showed faster acid development than the single culture. The resulting FWB had high protein (9%) and low fat content (0.2%). Increased viscosity, and antioxidant and antimicrobial activity were observed after fermentation. A viable cell count of 109 CFU/mL in FWB was achieved within 10 h fermentation, and it remained throughout storage at 15℃ for 28 d. Sensory analysis was also conducted, and compared to that of a commercial protein drink. The sensory scores of FWB were similar to those of the commercial protein drink in most attributes, except sourness. The sourness was highly related with the high lactic acid content produced during fermentation. The results showed that WPC and vegetable origin lactic acid bacteria isolated from kimchi might be used for the development of a high protein fermented beverage, with improved functionality and organoleptic properties. PMID:26761827

  6. Improvement of the fermentative activity of lactic acid bacteria starter culture by the addition of Mn²⁺.

    PubMed

    Cheng, Xin; Dong, Ying; Su, Ping; Xiao, Xiang

    2014-11-01

    Production of lactic acid bacteria (LAB) starter with raw material has received much scientific investigation, but little information is available on the influences of some trace elements on the growth and fermentative activity of LAB. Based on this fact, this paper aimed to investigate the effects of Mn(2+) on the performance of Lactobacillus plantarum CX-15 starter with Jerusalem artichoke (JA) as the main medium substrate. The results showed that Mn(2+) addition had a significant beneficial affect on the fermentative activity of L. plantarum CX-15 starter. In contrast, the lack of Mn(2+) would cause the subsequent fermentation significantly slower, whether the cell density in starter culture was higher or lower. The possible mechanism of these phenomenons was further elucidated by the time course analysis of the specific activities of metabolism key enzymes during the culture processes of L. plantarum CX-15 starter. Compared to the fermentation processes without Mn(2+) addition, it was found that Mn(2+) addition would enhance the lactate dehydrogenase (LDH) activity but reduce the activities of pyruvate dehydrogenase (PDH) and ATPase activity. Therefore, it could be concluded that the improvement of L. plantarum starter fermentative activity was probably a consequence of Mn(2+) acting as "metabolic switch," which regulated the metabolic flux from pyruvic acid to lactic acid and other metabolism pathway.

  7. Taxonomic structure of the yeasts and lactic acid bacteria microbiota of pineapple (Ananas comosus L. Merr.) and use of autochthonous starters for minimally processing.

    PubMed

    Di Cagno, Raffaella; Cardinali, Gainluigi; Minervini, Giovanna; Antonielli, Livio; Rizzello, Carlo Giuseppe; Ricciuti, Patrizia; Gobbetti, Marco

    2010-05-01

    Pichia guilliermondii was the only identified yeast in pineapple fruits. Lactobacillus plantarum and Lactobacillus rossiae were the main identified species of lactic acid bacteria. Typing of lactic acid bacteria differentiated isolates depending on the layers. L. plantarum 1OR12 and L. rossiae 2MR10 were selected within the lactic acid bacteria isolates based on the kinetics of growth and acidification. Five technological options, including minimal processing, were considered for pineapple: heating at 72 degrees C for 15 s (HP); spontaneous fermentation without (FP) or followed by heating (FHP), and fermentation by selected autochthonous L. plantarum 1OR12 and L. rossiae 2MR10 without (SP) or preceded by heating (HSP). After 30 days of storage at 4 degrees C, HSP and SP had a number of lactic acid bacteria 1000 to 1,000,000 times higher than the other processed pineapples. The number of yeasts was the lowest in HSP and SP. The Community Level Catabolic Profiles of processed pineapples indirectly confirmed the capacity of autochthonous starters to dominate during fermentation. HSP and SP also showed the highest antioxidant activity and firmness, the better preservation of the natural colours and were preferred for odour and overall acceptability.

  8. Variable carbon isotope fractionation expressed by aerobic CH 4-oxidizing bacteria

    NASA Astrophysics Data System (ADS)

    Templeton, Alexis S.; Chu, Kung-Hui; Alvarez-Cohen, Lisa; Conrad, Mark E.

    2006-04-01

    Carbon isotope fractionation factors reported for aerobic bacterial oxidation of CH 4(α) range from 1.003 to 1.039. In a series of experiments designed to monitor changes in the carbon isotopic fractionation of CH 4 by Type I and Type II methanotrophic bacteria, we found that the magnitude of fractionation was largely due to the first oxidation step catalyzed by methane monooxygenase (MMO). The most important factor that modulates the (α) is the fraction of the total CH 4 oxidized per unit time, which strongly correlates to the cell density of the growth cultures under constant flow conditions. At cell densities of less than 0.1 g/L, fractionation factors greater than 1.03 were observed, whereas at cell densities greater than 0.5 g/L the fractionation factors decreased to as low as 1.002. At low cell densities, low concentrations of MMO limit the amount of CH 4 oxidized, while at higher cell densities, the overall rates of CH 4 oxidation increase sufficiently that diffusion of CH 4 from the gaseous to dissolved state and into the cells is likely the rate-determining step. Thus, the residual CH 4 is more fractionated at low cell densities, when only a small fraction of the total CH 4 has been oxidized, than at high cell densities, when up to 40% of the influent CH 4 has been utilized. Therefore, since Rayleigh distillation behavior is not observed, δ 13C values of the residual CH 4 cannot be used to infer the amount oxidized in either laboratory or field-studies. The measured (α) was the same for both Type I and Type II methanotrophs expressing particulate or soluble MMO. However, large differences in the δ 13C values of biomass produced by the two types of methanotrophs were observed. Methylosinus trichosporium OB3b (Type II) produced biomass with δ 13C values about 15‰ higher than the dissimilated CO 2, whereas Methylomonas methanica (Type I) produced biomass with δ 13C values only about 6‰ higher than the CO 2. These effects were independent of the

  9. [The microflora of sourdough. XIX. The effect of temperature and dough yield on the proteolytic effect of lactic acid bacteria in sourdough].

    PubMed

    Spicher, G; Nierle, W

    1984-07-01

    During fermentation of sour dough the flour proteins are degraded. The proteolysis depends not only on lactic acid bacteria (Lactobacillus plantarum, L. brevis ssp. lindneri, L. fructivorans) but also on the conditions of fermentation of the sour dough. An increase of temperatures between 25 degrees C and 35 degrees C causes an increase in the amino acid content. The water content of the dough (T.A. 150/T.A. 210) influences the proteolytic activity of the bacteria to a lesser degree.

  10. Effect of linear alkylbenzene sulfonates on the growth of aerobic heterotrophic cultivable bacteria isolated from an agricultural soil.

    PubMed

    Sánchez-Peinado, María del Mar; González-López, Jesús; Rodelas, Belén; Galera, Vanesa; Pozo, Clementina; Martínez-Toledo, María Victoria

    2008-08-01

    An enrichment culture technique was used to isolate soil bacteria capable of growing in the presence of two different concentrations of linear alkylbenzene sulfonates (LAS) (10 and 500 microg ml(-1)). Nine bacterial strains, representatives of the major colony types of aerobic heterotrophic cultivable bacteria in the enriched samples, were isolated and subsequently identified by PCR-amplification and partial sequencing of the 16S rRNA gene. Amongst the isolates, strains LAS05 (Pseudomonas syringae), LAS06 (Staphylococcus epidermidis), LAS07 (Delftia tsuruhatensis), LAS08 (Staphylococcus epidermidis) and LAS09 (Enterobacter aerogenes), were able to grow in pure culture in dialysed soil media amended with LAS (50 microg ml(-1)). The three Gram-negative strains grew to higher cell numbers in the presence of 50 microg ml(-1) of LAS, compared to LAS-unamended dialysed soil medium, and were selected for further testing of their ability to use LAS as carbon source. However, HPLC analysis of culture supernatants showed that the three strains can tolerate but not degrade LAS when grown in pure cultures. A higher concentration of soluble phosphates was recorded in dialysed soil media amended with LAS (50 microg ml(-1)) compared to unamended control media, suggesting an effect of the surfactant that enhanced the bioavailability of P from soil. The presence of LAS at a concentration of 50 microg ml(-1) had an important impact on growth of selected aerobic heterotrophic soil bacteria, a deleterious effect which may be relevant for the normal function and evolution of agricultural soil.

  11. Survival, injury and inactivation of Escherichia coli 0157:H7, salmonella and aerobic mesophilic bacteria in apple juice and cider amended with nisin-edta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For health reasons, people are consuming fresh juices or minimally processed fruit and vegetable juices, thereby, exposing themselves to the risk of foodborne illness if such juices are contaminated with bacteria pathogens. Behavior of aerobic mesophilic bacteria, Escherichia coli O157:H7 and Salmon...

  12. Isolation and characterization of halophilic lactic acid bacteria isolated from "terasi" shrimp paste: a traditional fermented seafood product in Indonesia.

    PubMed

    Kobayashi, Takeshi; Kajiwara, Michika; Wahyuni, Mita; Kitakado, Toshihide; Hamada-Sato, Naoko; Imada, Chiaki; Watanabe, Etsuo

    2003-10-01

    Lactic acid bacteria from "terasi" shrimp paste, a highly popular fermented seafood in Indonesia were isolated and characterized. Viable cell counts were 10(4) to 10(6) cfu/g on MRS medium. All the isolates were catalase-negative, gram-positive cocci and were able to grow at 15% NaCl. Numerical phenotypic analysis showed that the isolates clustered into one group. However, they could be classified into two types: the Tetragenococcus halophilus group and the T. muriaticus group as revealed by a restriction fragment length polymorphism (RFLP) analysis and sequencing of the 16S rRNA gene. This study is the first to show that both species of Tetragenococcus are distributed in Indonesian fermented foods.

  13. A review of bacteriocinogenic lactic acid bacteria used as bioprotective cultures in fresh meat produced in Argentina.

    PubMed

    Castellano, P; Belfiore, C; Fadda, S; Vignolo, G

    2008-07-01

    Several lactic acid bacteria (LAB) associated with meat products are important natural bacteriocin producers. Bacteriocins are proteinaceous antagonistic substances that are important in the control of spoilage and pathogenic microorganisms. The use of LAB as bioprotective cultures to extend the shelf life of fresh meat can improve microbial stability and safety in commercial meat preservation. Lactobacillus curvatus CRL705 used as a protective culture in fresh beef is effective in inhibiting Listeria innocua and Brochothrix thermosphacta as well as the indigenous contaminant LAB, retaining its inhibitory effect at low temperatures and having a negligible effect on meat pH. In addition to the hurdle represented by low temperature and vacuum-packaging, the use of live cells of Lb. curvatus CRL705 seems more feasible from an economic point of view - and without legal restrictions - compared to the addition of purified bacteriocins. A description of meat-borne bacteriocins and their application in meat to extend shelf life is discussed.

  14. Isolation of lactic acid bacteria with inhibitory activity against pathogens and spoilage organisms associated with fresh meat.

    PubMed

    Jones, Rhys J; Hussein, Hassan M; Zagorec, Monique; Brightwell, Gale; Tagg, John R

    2008-04-01

    The use of lactic acid bacteria (LAB) as protective cultures in vacuum-packed chill-stored meat has potential application for assuring and improving food quality, safety and market access. In a study to identify candidate strains suitable for evaluation in a meat model, agar-based methods were employed to screen 181 chilled meat and meat process-related LAB for strains inhibitory to pathogens and spoilage organisms of importance to the meat industry. Six meat-derived strains, including Lactobacillus sakei and Lactococcus lactis, were found to be inhibitory to one or more of the target strains Listeria monocytogenes, Brochothrix thermosphacta, Campylobacter jejuni and Clostridium estertheticum. The inhibitory agents appeared to be either cell-associated or molecules released extracellularly with bacteriocin-like properties. Variations detected in the antimicrobial activity of LAB associated with changes to test parameters such as substrate composition underlined the importance of further in situ evaluation of the inhibitory strains in stored meat trials.

  15. Diversity and Stability of Lactic Acid Bacteria in Rye Sourdoughs of Four Bakeries with Different Propagation Parameters

    PubMed Central

    Viiard, Ene; Bessmeltseva, Marianna; Simm, Jaak; Talve, Tiina; Aaspõllu, Anu; Paalme, Toomas; Sarand, Inga

    2016-01-01

    We identified the lactic acid bacteria within rye sourdoughs and starters from four bakeries with different propagation parameters and tracked their dynamics for between 5–28 months after renewal. Evaluation of bacterial communities was performed using plating, denaturing gradient gel electrophoresis, and pyrosequencing of 16S rRNA gene amplicons. Lactobacillus amylovorus and Lactobacillus frumenti or Lactobacillus helveticus, Lactobacillus pontis and Lactobacillus panis prevailed in sourdoughs propagated at higher temperature, while ambient temperature combined with a short fermentation cycle select