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See detailApplication des biotechnologies post-récolte pour la valorisation des produits de terroirs marocains par des microorganismes sélectionnés impliqués dans la fermentation de fruits : cas du vinaigre
Mounir, Majid ULiege

Doctoral thesis (2016)

Dans cette étude, de nouvelles souches microbiennes (levures et bactéries acétiques) ont été isolées, sélectionnées, identifiées et caractérisées pour évaluer leur usage comme starters pour la production ... [more ▼]

Dans cette étude, de nouvelles souches microbiennes (levures et bactéries acétiques) ont été isolées, sélectionnées, identifiées et caractérisées pour évaluer leur usage comme starters pour la production industrielle de vinaigre de fruits. Dans un premier temps, la levure Saccharomyces cerevisiae YS-DN1 a été isolée à partir de dattes locales et étudiée pour ces pouvoirs de fermentation des sucres et de résistance aux différents facteurs de stress (éthanolique, thermique et osmotique). Cette souche s’est distinguée comme étant la plus performante dans la production d’éthanol en comparaison à deux autres souches industrielles de référence. En effet, YS-DN1 était la seule souche capable de se développer à une température entre 35 et 40°C en présence d’un taux alcoolique élevé (>8% éthanol) et une pression osmotique agressive (>18 °Brix). Dans un deuxième temps, deux souches de bactéries acétiques CV01 et AF01, identifiées par des techniques moléculaires comme étant affiliées à l’espèce Acetobacter pasteurianus, ont été isolées respectivement de cactus et de pommes. A l’issue des caractérisations physiologiques et des cinétiques de fermentation réalisées en erlens et en bioréacteurs (6 L, 20 L et 500 L), ces deux souches ont montré des pouvoirs de thermotolérance et d’acétification notables. L’étude enzymatique réalisée sur les enzymes membranaires ADH et ALDH formant le complexe enzymatique impliqué dans le processus d’oxydation de l’éthanol a révélé que, contrairement aux souches de référence, ces enzymes maintiennent une activité normale à haute température (38°C). L’étude cinétique en bioréacteur 20 L a montré que la souche CV01 était moins sensible à la variation de la composition du milieu de fermentation et a pu produire plus d’acide acétique (10 g/L) que la souche AF01. Durant le même cycle de fermentation, la souche CV01 était notablement la seule souche capable d’orienter son mécanisme métabolique pour la production de l’acide gluconique simultanément avec l’acide acétique. Par ailleurs, la méthode des surfaces de réponse (RSM) a été utilisée pour l’optimisation de la production en biomasse de la souche CV01. Les valeurs optimales des facteurs influents, à savoir l’éthanol, l’acide acétique, le glucose et le pH, permettant d’obtenir le maximum de biomasse cellulaire (2.21 g/L) étaient de 28.18 g/L, 10.12 g/L, 15.15 g/L et 5.33, respectivement. Dans une troisième partie, la souche A. pasteurianus CV01 a été évaluée pour sa capacité à résister aux conditions de stress thermique en bioréacteur. Les résultats obtenus montrent une habilité de cette souche à contrecarrer l’augmentation excessive de température (>35°C) au cours d’un cycle de fermentation sans refroidissement. En outre, un protocole de démarrage de fermentation en mode semi-continu a été proposé et adopté pour la production de vinaigre de fruits en bioréacteur 500 L. La caractérisation aromatique du vinaigre de pomme produit à l’échelle pilote moyennant la technique de l’espace de tête – microextraction en phase solide (HS-SPME) – a permis d’identifier dans la composition de son arôme des molécules associées à des descripteurs généralement appréciés . Ces souches, caractérisées pour leur thermotolérance notable, pourront être utilisées comme starters pour la production à grande échelle de vinaigre de fruits. [less ▲]

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See detailSemi-continuous fermentation of a thermotolerant and high acetic acid producing Acetobacter pasteurianus bacterium
Mounir, Majid ULiege; Thonart, Philippe ULiege; Ismaili Alaoui, Mustapha et al

Conference (2016, September 14)

Among 63 strains isolated from fruits and homemade vinegars from different ecosystems of Morocco, a thermotolerant bacterium with high production of acetic acid was selected and evaluated for its ability ... [more ▼]

Among 63 strains isolated from fruits and homemade vinegars from different ecosystems of Morocco, a thermotolerant bacterium with high production of acetic acid was selected and evaluated for its ability to perform efficient acetous fermentation at high temperature in a bioreactor. CV01 strain, isolated from cactus (Opuntia ficus-indica), was considered to be an Acetobacter pasteurianus sp. according to phylogenetic study based on 16s rDNA gene sequence analysis. An optimal culture medium containing initial concentrations of acetic acid and ethanol of 1% (v/v) and 4% (v/v), respectively, was used. The growth kinetics of this isolate were monitored in flasks and compared with those of the wild type LMG 1625 mesophilic strain and the thermoresistant Acetobacter senegalensis reference strain. The CV01 strain exhibited abundant growth along with high amount of produced acetic acid at high temperature (41°C). Subsequently, a 20-L stirred tank bioreactor was used to assess thermotolerance and acidoresistance properties of the selected strain during semi-continuous acetic acid fermentation at 38°C. Interestingly, a total amount of 13.4% (w/v) acetic acid was yielded at the end of fermentation. Moreover, this bacterium could produce during the same fermentation process a final concentration of 11.2 g/L gluconic acid, a sensory quality indicator in vinegar production. Finally, the enzymatic study showed that CV01 strain exhibited high ADH and ALDH enzyme activity at 38°C compared with the mesophilic reference strain LMG 1632, which was significantly susceptible to thermal inactivation. [less ▲]

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See detailMaîtrise de la fermentation alcoolique sous stress éthanolique, thermique et osmotique de la souche Saccharomyces cerevisiae YSDN1 en vue de la préparation du vinaigre de fruits
Mounir, Majid ULiege; Belgrire, Malika; Lahnaoui, Safaa et al

in Revue Marocaine des Sciences Agronomiques et Veterinaires (2016), 4(2), 86-95

La présente étude a pour but d’isoler, d’identifier et de caractériser de nouvelles souches de levures d’intérêt industriel. Un total de 54 levures ont été isolées et identifiées à partir de produits ... [more ▼]

La présente étude a pour but d’isoler, d’identifier et de caractériser de nouvelles souches de levures d’intérêt industriel. Un total de 54 levures ont été isolées et identifiées à partir de produits agricoles brutes et de sous-produits de l’industrie agro-alimentaire. Parmi ces isolats, quatre souches ont été retenues, purifiées et testées pour leur performance de fermentation sur un jus de dattes de variété Bouslikhène. D’après le séquençage du gène 18S de l’ADN ribosomal, les deux souches YS-DN1 et YS-M isolées respectivement à partir des dattes et de la mélasse ont été identifiées appartenant à l’espèce Saccharomyces cerevisiae. Par ailleurs, les deux autres souches YS-OPM et YS-G isolées des olives et des raisins appartiennent respectivement aux espèces Kluyveromyces marxianus, avec 78% d’homologie et Candida utilis à 89% d’homologie. D’autre part, la souche YS-DN1, s’est identifiée comme la plus performante dans la production d’éthanol en comparaison à deux autres souches industrielles de référence. La levure YS-DN1 était l’unique souche capable de croitre à une température entre 35 et 40°C en présence d’un taux alcoolique élevé et une pression osmotique agressive. Finalement, la production de la biomasse cellulaire de la souche YS -DN1 a été améliorée par optimisation des facteurs température, Brix et pH fixés respectivement à 29.75°C, 15.7% et 4.15. Ces valeurs ont permis d’obtenir un maximum de cellules de l’ordre de 8.4x108 UFC/ml. Il a été conclu que cette souche pourrait bien s’adapter à des usages industriels pour la production du vinaigre de fruits à grande échelle. [less ▲]

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See detailOptimization of biomass production of Acetobacter pasteurianus KU710511 as a potential starter for fruit vinegar production
Mounir, Majid ULiege; Shafiei, Rasoul; Zarmehrkhorshid, Raziyeh ULiege et al

in African Journal of Biotechnology (2016), 15(27), 1429-1441

The objective of the present work was first the isolation of novel acetic acid bacteria strains from natural Moroccan habitats, and then, the evaluation of their ability to produce microbial starters for ... [more ▼]

The objective of the present work was first the isolation of novel acetic acid bacteria strains from natural Moroccan habitats, and then, the evaluation of their ability to produce microbial starters for vinegar production on a large scale. The strains were isolated from figs, dates, cactus, and traditional fruit vinegars. Four strains, selected from a total of 63 isolates, were confirmed as belonging to Acetobacter species according to biochemical and molecular studies based on 16s rRNA sequence analysis. Acetous fermentation tests, performed on date and apple fermented juices using selected Acetobacter strains, showed a high capacity of acidification. The most efficient strain KU710511, isolated from Morrocan cactus (Opuntia ficus-indica), was identified as Acetobacter strain closely related to A. pasteurianus and yielded 42.5 g/L acidity in apple juice. Cell growth optimization was carried out for KU710511 using response surface methodology (RSM). The linear, quadratic, and interaction effects of four factors—ethanol, acetic acid, glucose concentrations and pH—were studied by the application of a central composite design. Thirty experiments were designed to predict the maximum concentration of cell biomass. The optimal calculated values of ethanol, acetic acid, glucose and pH allowing the prediction of the maximum biomass production (2.21 g/L) were 28.18 g/L, 10.12 g/L, 15.15 g/L and 5.33, respectively. Subsequently, further batch fermentations were carried out in a 6-L lab-bioreactor at optimal and thermal stress conditions. The results were in line with the predicted values. It can be concluded that the studied strain is well suited to be used as a parental strain to prepare a starter for fruit vinegar production. [less ▲]

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See detailEnhanced biomass production of a novel Acetobacter strain isolated from Moroccan biotopes using response surface methodology approach
Mounir, Majid ULiege; Hamas, Khadija; Tamraoui, Khadija et al

Conference (2016, March 21)

The objective of this work was first the isolation of novel acetic acid bacteria strains from natural Moroccan habitats, and then, the evaluation of their ability to produce microbial starters for vinegar ... [more ▼]

The objective of this work was first the isolation of novel acetic acid bacteria strains from natural Moroccan habitats, and then, the evaluation of their ability to produce microbial starters for vinegar production in large-scale. The isolation was made from figs, dates, cactus, and traditional fruit vinegars. Four strains, selected from a total of 63 isolates were confirmed to be belonged to Acetobacter species according to biochemical tests and molecular study based on 16s rDNA sequence analysis. Acetic acid fermentation tests, performed on date and apple fermented juices by the selected Acetobacter strains, showed high capacity of acidification. The most efficient strain, isolated from cactus vinegar, yielded an acidity of about 42.5 g/L on apple juice. A cell growth optimization was carried out on the most efficient strain using the response surface methodology (RSM). The linear, quadratic and interaction effects of four factors; ethanol, acetic acid, glucose and pH were studied by the application of a central composite design. 30 experiments were designed to predict the maximum concentration of cell biomass. The optimal calculated values of ethanol, acetic acid, glucose and pH allowing the prediction of the maximum biomass production (2.2 g/L) were 28.18 g/L, 10.12 g/L, 15.15 g/L and 5.33, respectively. Subsequently, further batch fermentations were carried out in a 6 L lab-bioreactor using the optimased culture medium. The results were in line with the predict values. It was concluded that the studied strain is well suited to be used as parental strain to prepare a starter for vinegar fruit production. [less ▲]

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See detailSimultaneous production of acetic and gluconic acids by a thermotolerant Acetobacter strain during acetous fermentation in a bioreactor
Mounir, Majid ULiege; shafiei, rasoul; Zarmehrkhorshid, Raziyeh et al

in Journal of Bioscience and Bioengineering (2016), 121(2), 166-171

The activity of bacterial strains significantly influences the quality and the taste of vinegar. Previous studies of acetic acid bacteria have primarily focused on the ability of bacterial strains to ... [more ▼]

The activity of bacterial strains significantly influences the quality and the taste of vinegar. Previous studies of acetic acid bacteria have primarily focused on the ability of bacterial strains to produce high amounts of acetic acid. However, few studies have examined the production of gluconic acid during acetous fermentation at high temperatures. The production of vinegar at high temperatures by two strains of acetic acid bacteria isolated from apple and cactus fruits, namely AF01 and CV01, respectively, was evaluated in this study. The simultaneous production of gluconic and acetic acids was also examined in this study. Biochemical and molecular identification based on a 16s rDNA sequence analysis confirmed that these strains can be classified as Acetobacter pasteurianus. To assess the ability of the isolated strains to grow and produce acetic acid and gluconic acid at high temperatures, a semi-continuous fermentation was performed in a 20-L bioreactor. The two strains abundantly grew at a high temperature (41°C). At the end of the fermentation, the AF01 and CV01 strains yielded acetic acid concentrations of 7.64% (w/v) and 10.08% (w/v), respectively. Interestingly, CV01 was able to simultaneously produce acetic and gluconic acids during acetic fermentation, whereas AF01 mainly produced acetic acid. In addition, CV01 was less sensitive to ethanol depletion during semi-continuous fermentation. Finally, the enzymatic study showed that the two strains exhibited high ADH and ALDH enzyme activity at 38°C compared with the mesophilic reference strain LMG 1632, which was significantly susceptible to thermal inactivation. [less ▲]

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See detailApplication des biotechnologies pour la valorisation des produits des oasis Marocaines : Préparation du vinaigre aromatisé et du sirop de dattes
Mounir, Majid ULiege; Atfaoui, Khadija; En-Nassiri, Houda et al

Conference (2015, October 16)

Dans les oasis du Sud du Maroc, les dattes, constituent la composante principale du régime alimentaire et la trésorerie de base pour les populations oasiennes. Plus de 40% de la production dattière est ... [more ▼]

Dans les oasis du Sud du Maroc, les dattes, constituent la composante principale du régime alimentaire et la trésorerie de base pour les populations oasiennes. Plus de 40% de la production dattière est composée de variétés de faible valeur marchande. Les techniques de récolte actuellement pratiquées aux niveaux des oasis demeurent archaïques et engendrent des pertes qui peuvent atteindre 30 % sur les lieux de production. L’analyse du savoir-faire des populations oasiennes a montré que ces dernières préparent des sirops et du vinaigre traditionnels de mauvaise qualité. L’application des biotechnologies de production des starters en vue de la production de vinaigres de dattes aromatisés aux plantes aromatiques et médicinales constitue une alternative valable pour la valorisation des dattes de mauvaises qualités commerciales. Ainsi, la rationalisation de l’ensemble de ces technologies en vue de valoriser le savoir-faire locale selon les règles de bonnes pratiques de production et d’hygiène et répondant à la législation marocaine s’avère nécessaire. En effet, selon l’arrêté 2.10.385, la dénomination « vinaigre » est réservée aux produits obtenus exclusivement par un processus biologique de double fermentation alcoolique et acétiques ou autres éléments d’origines agricole ayant une acidifié > 5° acétique et un degré d’alcool < 0,5. Par ailleurs, la réglementation marocaine réserve la dénomination sirop aux produits concentrés dont le degré brix doit strictement dépasser 50°, obtenus par dissolution de matières sucrantes glucidiques dans l’eau. Le taux du 5 HMF ne doit pas, en outre, dépasser les 300 mg/kg. Cas du vinaigre de datte : Le procédé traditionnel a permi d’obtenir un vinaigre inapte avec des critères qualitatifs qui ne respectent pas les normes en vigueur. Le procédé industriel au niveau de l’acetateur s’est montré beaucoup plus performant, avec une productivité qui est 18 fois supérieure à celle obtenue par le procédé traditionnel , ayant abouti à des vinaigres conformes à la législation et bien acceptés par le panel de dégustation . Cas du Sirop de datte : Le procédé traditionnel a permi d’obtenir un sirop inapte avec taux de 5-HMF 10 fois supérieur par rapport à celui préparé par la boule de concentration sous vide. Les deux produits se sont révelés très concentrés en éléments minéraux par rapport à leurs homologues préparés par des procédés traditionnels. [less ▲]

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See detailNovel thermotolerant Acetobacter pasteurianus strains isolated from Moroccan local products destined to industrial vinegar production using substandard fruits
Mounir, Majid ULiege; Shafiei, Rasoul; Hamouda, Allal et al

Poster (2015, March 03)

Six strains of acetic acid bacteria were isolated from Moroccan local products and their potential as industrial strains was evaluated in lab-bioreactor. Two of them, namely AF01 and CV01, isolated from ... [more ▼]

Six strains of acetic acid bacteria were isolated from Moroccan local products and their potential as industrial strains was evaluated in lab-bioreactor. Two of them, namely AF01 and CV01, isolated from apple and cactus fruit, respectively were selected and their responses to high temperature were assessed. Biochemical and molecular study based on 16s rDNA sequence analysis confirmed that the two isolated strains belong to Acetobacter pasteurianus with 99% homology. Their growth and acetic acid production were compared with (1) the thermoresistant reference strain, Acetobacter senegalensis and (2) other mesophilic strains of Acetobacter pasteurianus (LMG 1632, LMG 1607, LMG 1701, DSM 2324 and DSM 4491). The two strains showed abundant growth and noticeable acetic acid production ability at high temperatures (38 to 41°C). A thermophilic character was observed for AF01 strain. Indeed, this bacterium grew better at 38 than 30°C. Subsequently, a semi-continuous fermentation was performed in a 20L bioreactor for the both selected strains. A total amount of 7.64% and 10.08% (w/v) acetic acid was achieved at the end of fermentation for AF01 and CV01 strains respectively. Interestingly, CV01 was able to produce acetic acid and gluconic acid simultaneously during acetic acid fermentation. This is an important feature for AAB used in vinegar industry. Finally, the enzymatic study showed that the two strains exhibited high ADH and ALDH enzyme activity at either 30 or 38°C as compared to the mesophilic reference strain LMG 1632 which exhibited remarkable thermal inactivation rate. Since the selected strains exhibited appropriate features, it is concluded that they can be considered as industrial starins for production of vinegar from substandard fruits. [less ▲]

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See detailIsolation of acetic acid bacteria from Moroccan biotopes and optimization of their biomass production using response surface methodology
Mounir, Majid ULiege; Hamouda, Allal; Ismaili Alaoui, Mustapha et al

Poster (2015, January 30)

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See detailMolecular analysis of viable but non culturable cells formed during gluconic acid fermentation
Zarmehrkhorshid, Raziyeh; Shafiei, Rasoul; Mounir, Majid ULiege et al

Poster (2015, January 30)

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See detailEVALUATION OF THERMOTOLERANT ACETOBACTER PASTEURIANUS STRAINS ISOLATED FROM MOROCCAN FRUITS CATALYZING OXIDATIVE FERMENTATION AT HIGH TEMPERATURE.
Mounir, Majid ULiege; Shafiei, R.; Zarmehrkhorshid, R. et al

in Communications in Agricultural and Applied Biological Sciences (2015), 80(1), 37-43

Six strains of acetic acid bacteria were isolated from Moroccan local products and their potential as industrial strains was evaluated in lab-bioreactor. Three of them, namely TAV01, AF01 and CV01 ... [more ▼]

Six strains of acetic acid bacteria were isolated from Moroccan local products and their potential as industrial strains was evaluated in lab-bioreactor. Three of them, namely TAV01, AF01 and CV01, isolated from traditional apple vinegar, apple and cactus fruit, respectively were selected and their responses to high temperature were assessed. Morphological and biochemical identification confirmed that these strains belong to Acetobacter species. Their growth and acetic acid production were compared with the thermoresistant reference strain, Acetobacter senegalensis and mesophilic strains of Acetobacter pasteurianus. The two strains AF01 and CV01 showed abundant growth and noticeable acetic acid production ability at high temperatures (38 to 41 degrees C). A thermophilic character was observed for AF01 strain. Indeed, this bacterium grew better at 38 than 30 degrees C. [less ▲]

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See detailValue addition of some Moroccan regional products by liquid fermentation: production of date and apple vinegars
Mounir, Majid ULiege; Shafiei, Rasoul; Zarmehrkhorshid, Razieh et al

Poster (2014, December 16)

Six strains of acetic acid bacteria were isolated from Moroccan local products and evaluated for their industrial vinegar production potential. Two of them, namely AF01 and CV01, isolated from apple ... [more ▼]

Six strains of acetic acid bacteria were isolated from Moroccan local products and evaluated for their industrial vinegar production potential. Two of them, namely AF01 and CV01, isolated from apple (Malus domestica) and cactus (Opuntia ficus-indica) fruits, respectively, were selected and investigated for their thermoresistant and thermophilic properties. A biochemical and molecular study based on a 16SrDNA gene sequence analysis confirmed that the two isolated strains belong to Acetobacter pasteurianus with 99 % of homology. Their growth and acetic acid production capacity were compared with (1) the thermoresistant reference strain A. senegalensis isolated from mango (Senegal) and (2) other, wild acetic strains belonging to A. pasteurianus (LMG 1632, LMG 1607, LMG 1701, DSM 2324 and DSM 4491). The two strains showed very good growth and noticeable acetic acid production ability at high temperatures (38 to 41°C). A thermophilic character was noted for AF01 strain. Indeed, this bacterium grew better at 38 than at 30°C. Subsequently, a semi-continuous fermentation was performed in a 20L Bioreactor for both selected strains. A total amount of 7.64% and 10.08% acetic acid was achieved at the end of fermentation, respectively for AF01 and CV01 strains. Process fermentation of CV01 strain was marked by the ability to produce gluconic acid during acetic fermentation. Finally, an enzymatic study was carried out on the selected strains AF01 and CV01 to confirm the tolerance of their enzymes responsible for acetic fermentation process to high temperature. Results clearly showed that the two strains exhibited high ADH and ALDH enzyme activity at either 30 or 38 °C as compared to the mesophilic reference strain LMG 1632 which exhibited marked thermal inactivation rate. It is concluded that the two selected strains are well-suited to industrial use for vinegar production in Morocco. [less ▲]

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See detailValorisation des produits de terroirs par fermentation liquide : Production de vinaigres et sirops de Dattes, Cactus et Pommes
Mounir, Majid ULiege; Hamouda, Allal; Thonart, Philippe ULiege et al

Conference (2013, December 04)

Morocco is continuously looking for developping Food industry through various programs (Moroccan Green Plan, National Initiative for Human Development, Emergence Plan. etc). It remains one of the most ... [more ▼]

Morocco is continuously looking for developping Food industry through various programs (Moroccan Green Plan, National Initiative for Human Development, Emergence Plan. etc). It remains one of the most major producers of fruit and vegetables countries (1.8 to 3 million tons, APEFEL 2012). The factual and numerical analysis of Moroccan fruit production showed that more than 30% of fruit production is lost during post harvest. The biochemical characterization of these local products (Dates, Cactus and Apples) reveals a rich composition of sugars and minerals needed for the growth of contamination microorganisms at the site of production. The objective of this study is to valorize post harvest fruit using biotechnological processes through the selection of endogenous and endemic microbial strains to prepare syrups, vinegars and starters for industrial use. Twenty-two samples (fruits, traditional alcohols and vinegars) from different regions of Morocco were used as substrates for isolation of bacteria and yeasts. Microbial isolates were there subjected to a biochemical, metabolic and molecular study for the identification and characterization. [less ▲]

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