Gluten proteolysis as alternative therapy for celiac patients: A mini-review

Celiac disease (CD) results from damage to the small intestinal mucosa due to an inappropriate immune response to a cereal protein (wheat, rye, barley). The only treatment for CD is life-long avoidance of gluten proteins. Gluten-free products are not widely available and usually more expensive. That is why; there is an urgent need to develop an alternative therapy. Enzymatic degradation of gluten among other approaches, abolishing its immunogenic and toxigenic activities, is an attractive alternative strategy for oral therapy in CD. Several proteases following different approaches were studied. This review focuses on enzymes (microbial or vegetal) designed to digest gluten. Also, recent biotechnological procedures that use microorganisms (cell factories for enzymes) as starter culture to eliminate gluten are reviewed in this manuscript. Keywords: Celiac disease, gluten, proteolytic activity, lactic acid bacteria, therapyAfrican Journal of Biotechnology Vol. 11(29), pp. 7323-7330, 10 April, 201

Technological, functional and safety aspects of enterococci in fermented vegetable products: a mini-review

Bacteria belonging to the genus Enterococcus spp.—a member of the lactic acid bacteria group—are natural inhabitants of various environments, including vegetable products. Although some strains show pathogenic determinants, overall these bacteria may have some pro-technological features. Some enterococci have been described as potential starter or protective cultures in the dairy industry, since they contribute to the organoleptic and quality characteristics of dairy products. Although several fermented vegetable products have a long history in human nutrition, studies regarding autochthonous enterococci and their application to fermented vegetable foods are much less numerous than those concerning dairy foods. In this review, after a general overview of enterococci, their presence and role in fermented vegetable foods (including table olives, sauerkraut, kimchi, tomato juice, French beans, caper berries and cereal-based products) will be covered

Effect of Oxygen and Redox Potential on Glucose Fermentation in Thermotoga maritima under Controlled Physicochemical Conditions

Batch cultures of Thermotoga maritima were performed in a bioreactor equipped with instruments adapted for experiments performed at 80°C to mimic the fluctuating oxidative conditions in the hot ecosystems it inhabits. When grown anaerobically on glucose, T. maritima was shown to significantly decrease the redox potential (Eh) of the culture medium down to about −480 mV, as long as glucose was available. Addition of oxygen into T. maritima cultures during the stationary growth phase led to a drastic reduction in glucose consumption rate. However, although oxygen was toxic, our experiment unambiguously proved that T. maritima was able to consume it during a 12-hour exposure period. Furthermore, a shift in glucose metabolism towards lactate production was observed under oxidative conditions

Improvement of a pesticide immunosensor performance using site-directed antibody immobilisation and carbon nanotubes

The potential toxicity of pesticide residues in drinking water has meant a rigid regulation for the appearance of these pollutants. Thus, in this work, we developed a new immunosensor for atrazine detection. We focused on the optimisation of the antibody immobilisation method on sensor surface for the enhancement of the biosensor sensitivity. First, with site-directed immobilisation of rabbit anti-atrazine antibodies using goat anti-rabbit immunoglobulin, a detection limit of 0.5 ng/mL was obtained. This value is 20 times lower than the detection limit obtained with non-oriented antibodies. The second way to improve immunosensor sensitivity consisted of the addition of carbon nanotubes (CNT). As result of using these CNT, detection limit has been improved again from 0.5 ng/mL to 100 pg/mL.This work was financially supported by the PCI cooperation project between Spain and Tunisia.Marrakchi, M.; Helali, S.; Soto Camino, J.; González Martínez, MÁ.; Abdelghani, A.; Hamdi, M. (2013). Improvement of a pesticide immunosensor performance using site-directed antibody immobilisation and carbon nanotubes. International Journal of Nanotechnology. 10:496-507. doi:10.1504/IJNT.2013.053519S4965071

OPTIMISATION DE L’HYDRODYNAMIQUE D’UN PHOTOBIOREACTEUR TUBULAIRE DE TYPE AIRLIFT FAVORISANT LA FORMATION DE BIOFLOCS

L'augmentation de la population mondiale et de l'urbanisation qui sont à l'origine du changement climatique ont poussé les gouvernements à imposer des politiques pour réduire les émissions des gaz à effet de serre (GES). Par ailleurs les procédés de traitement biologique des eaux usées sont pénalisés énergétiquement et ils ne sont pas durables par leur consommation d’oxygène, les nuisances causées par les boues et les odeurs et par l’émission des gaz à effet de serre particulièrement le CO2. L'utilisation des microalgues pour traiter les eaux usées fait l'objet d'une attention croissante dans le monde car elle est considérée comme un nouveau moyen de traitement des eaux usées. En particulier, l'intégration de microalgues dans le cadre de procédés d’épuration multitrophiques permet d’envisager des solutions de traitement des eaux sans apport d'O2 et sans rejet de CO2. Il est communément admis que la culture à grande échelle et l'application commerciale des microalgues sont limitées par le développement du photobioréacteur (PBR). Bien qu'il existe des nombreux types de PBR pour la culture pure de microalgues dans des milieux de culture définis, un nouveau design de PBR doit être envisagé dans le cas de cultures multitrophiques utilisées pour l’épuration des eaux. Un PBR tubulaire avec airlift a donc été conçu. Un pilote a été construit pour étudier les aspects hydrodynamiques et le transfert de matière, dans le but d’optimiser le traitement des eaux usées Afin de minimiser la formation de biofilm sur la paroi et limiter la diffusion de la lumière, un écoulement avec des flocs des microalgues est généré. Le PBR d’étude conçue a servi de base aux études de transferts hydrodynamiques et biologiques. Les études hydrodynamiques (traçage conductimétrique) ont donné accès aux vitesses d’écoulement, le temps de circulation et le temps de mélange. Différents débits de gaz et différents types et positions de l’injecteurs de gaz ont été testés. En complément, les performances de transfert de matière gaz-liquide du réacteur ont été déterminées, afin de confirmer la possibilité de transférer efficacement l’oxygène produit photosynthétiquement Sur base des informations expérimentales collectées, le design de PBR et les conditions opératoires optimales pour une culture active de microalgues ont été optimisés. Les facteurs pris en compte sont le temps de séjour hydraulique, le transfert de matière gaz-liquide et le temps de mélange. L’objectif est d’assurer une distribution adéquate (uniforme et dans la gamme optimale) des concentrations en nutriments, en gaz O2 et CO2, ainsi que de la lumière, dans l’ensemble du réacteur.TRAITEMENT DES EAUX USEES SANS APPORT D’O2 ET SANS DEGAGEMENT DE CO2 ET DEVELOPPEMENT D’UN PHOTOBIOREACTEUR INNOVANT3. Good health and well-bein

Effect of Oxygen and Redox Potential on Glucose Fermentation in Thermotoga maritima under Controlled Physicochemical Conditions

Batch cultures of Thermotoga maritima were performed in a bioreactor equipped with instruments adapted for experiments performed at 80 • C to mimic the fluctuating oxidative conditions in the hot ecosystems it inhabits. When grown anaerobically on glucose, T. maritima was shown to significantly decrease the redox potential (Eh) of the culture medium down to about −480 mV, as long as glucose was available. Addition of oxygen into T. maritima cultures during the stationary growth phase led to a drastic reduction in glucose consumption rate. However, although oxygen was toxic, our experiment unambiguously proved that T. maritima was able to consume it during a 12-hour exposure period. Furthermore, a shift in glucose metabolism towards lactate production was observed under oxidative conditions

Nouvelle conception d'un procede de depollution biologique des margines, effluents liquides de l'extraction de l'huile d'olive

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 78951 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Antioxidant Capacity and Phenolic Content in Olive Leaf Tisane as Affected by Boiling Treatment

This paper investigated the effect of preparation method on the quality of olive leaf tisane. Secondly, it aimed at evaluating and understanding the effect of boiling treatment on phenolic compounds and antioxidant capacity of an aqueous extract of olive leaves. The Phenolic content was determined by Folin-Ciocalteu method. The antioxidant capacity was assessed by ABTS+ method. The Phenolic content and antioxidant capacity depended on extraction procedure of olive leaf tisane. It was found that boiling leads to a decrease in the phenolic content and a rise of antioxidant capacity of aqueous extract from olive leaves. The mass molecular distribution of the polymeric aromatic fraction was analyzed by gel filtration chromatography on Sephadex G50. Results suggested the hydrolysis of phenolic polymers following boiling. Moreover, HPLC analyses showed an increase in rutin, oleuropein and caffeic acid levels in treated sample. As a conclusion, thermal processing could be useful for enhancing the antioxidant capacity and the extractability of phenolic compounds in olive leaf tisane

Microbiological, Biochemical, and Functional Aspects of Fermented Vegetable and Fruit Beverages

In recent years, the request for the functional beverages that promote health and wellness has increased. In fact, fermented juices are an excellent delivering means for bioactive components. Their production is of crucial importance to supply probiotics, in particular, for people with particulars needs like dairy-product allergic consumers and vegetarians. This review focuses on recent findings regarding the microbial composition and the health benefits of fermented fruit and vegetable beverages by lactic acid bacteria, kefir grains, and SCOBY as well as discussing the metabolites resulting from these fermentations process. Moreover, limits that could restrain their production at the industrial level and solutions that have been proposed to overcome these constraints are also reviewed

Etude taxonomique de bactéries sulfato-réductrices originaires d'écosystèmes marins et hydrothermaux terrestres tunisiens (potentialités oxydo-réductrices de l'arsenic)

Les bactéries sulfato-réductrices (BSR) sont très répandues dans la nature contribuant à la minéralisation de la matière organique qui est remarquable dans les environnements marins et extrêmes. Des études portant sur la biodiversité des BSR ont été conduites sur des échantillons de milieux marins et de sources hydrothermales tunisiens. Des méthodes de microbiologie et de taxonomie moléculaire nous ont permis : de mettre en évidence la présence d une diversité de BSR appartenant surtout aux genres Desulfovibrio, Desulfotomaculum et Thermodesulfovibrio,de caractériser trois nouvelles espèces appartenant respectivement aux genres précités. Les potentialités oxydo-réductives de l arsenic ont été recherchées chez les souches isolées. La réduction indirecte de l As(V) a aussi été démontrée. Grâce à la présence d H2S, la toxicité du métal est largement amoindrie. En condition de microaérobiose, nous avons montré, pour la première fois, chez deux souches la capacité d oxyder l'As(III) en l'As(V)Sulfate-reducing bacteria (SRB) are widespread in nature where they contribute significantly to organic matter mineralization through the sulfur cycle. This contribution is particularly remarkable in marine sediments where they can take part up to 50% of organic matter oxidation, although their ecological role is important as well in the extreme environments. Beside their capacity to reduce sulfur compounds (sulfate, thiosulfate, elementary sulfur), SRB have also the ability to reduce heavy metals and metalloids. Studies related to the biodiversity of SRB were conducted on samples of marine sediments and hydrothermal terrestrial springs, located in the North part of Tunisia. Microbiological approaches coupled with molecular taxonomy based on the analysis of sequences of genes encoding for the ARNr 16S, allowed us to: (i) provide evidence of the existence of a great diversity of SRB belonging to genera Desulfovibrio, Desulfotomaculum and Thermodesulfovibrio then, (ii) to isolate and characterize three new species belonging to the above mentioned genera. We examined the oxydo-reductive capacities of our isolates towards arsenic compounds. Seven of these SRB showed the ability to directly reduce arsenate [As(V)] to arsenite [As(III)] without energy conservation. Indirect reduction of As(V) linked to biological sulfide production was also shown. The presence of H2S largely decreased metal toxicity. Under microaerobic conditions (0.5% and 1% of O2 in the gas phase), we demonstrated for the first time, that two of our isolates, HEB223 and Lam5, were able to oxidize arsenite to arsenateAIX-MARSEILLE1-BU Sci.St Charles (130552104) / SudocSudocFranceF