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Auteur Mahmoud Kitouni |
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Affiner la recherche Interroger des sources externesBiodiversité des actinomycètes halophiles et halotolérants isolés à partir de trois sites Ramsar situés au niveau de la Wilaya d’Oum El Bouaghi. / Chamss eddine Djaballah
Titre : Biodiversité des actinomycètes halophiles et halotolérants isolés à partir de trois sites Ramsar situés au niveau de la Wilaya d’Oum El Bouaghi. Type de document : texte imprimé Auteurs : Chamss eddine Djaballah, Auteur ; Mahmoud Kitouni, Auteur Mention d'édition : 28/01/2021 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2021 Importance : 175 f. Format : 30 cm. Note générale : 1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Microbiologie: Ecologie Microbiennes biodiversité culturomics Streptomyces massilialgeriensis sp. nov. actinomycètes Ramsar écosystème extrême biodiversity Actinomycetes extreme ecosystem التنوع البيولوجي الأكتينوميسيت رامسار البيئة القاسية Index. décimale : 570 Sciences de la vie. Biologie Résumé :
This work represents a first study of the biodiversity of the actinomycetes inhabitants three Sebkhas protected by the Ramsar-Algeria convention. The physicochemical analyzes of the soil samples revealed extremely high salinities, basic or very basic pH, low percentages of moisture, moderate or very high percentages of organic matter. These results also showed that samples of sebkha Annk Djemel belong to the ""clay"" and ""Clay loam"" classes, samples of sebkha Guellif belong to the ""clay loam"" and ""sandy-clay loam"" classes and samples of sebkha Et Taref belong to the ""clay"" class. An isolation of actinomycetes from the soil has been achieved by the use of conventional methods and / or Culturomics. The enumeration results revealed that the number of actinomycetes could reach to
2.105 CFU/g of soil. Based on the enumeration results, a statistical analysis, carried out by the application of non-parametric tests of Kruskal-Wallis and Mann-Whitney, revealed that culture media relatively poor in nutrients and the concentration 5% of NaCl are the most favorable in the isolation of actinomycetes. The competitive effect of bacterial and fungal flora has also been highlighted. Following the isolation protocols adopted, we were able to purify and store a total of 204 isolates, all Gram (+), of which 108 isolates were derived from conventional isolation techniques and 96 isolates were obtained by the Culturomics method. Identification by the MALDITOF MS and sequencing of the 16S rDNA methods allowed us to identify a new species that we named Streptomyces massilialgeriensis sp. nov. and to assign certain other isolates to the genera Streptomyces, Nocardiopsis and Actinomyces. Other isolates have been identified as Bacillus, Virgibacillus, Gracilibacillus, Staphylococcus, Flavonifactor and Halobacillus. The activity test, carried out by the agar plug diffusion method, of 13 selected isolates belonging to the genera Streptomyces and Nocardiopsis against multidrug-resistant bacteria reveal interesting zones of inhibition of the isolate S20 against K. pneumoniae CSUR P1596 (coli R), E. coli CSUR P4969 (coli R, HLP), E. coli CSUR P5139 (carba R) and P. mirabilis CSUR P2049 (oxa-48), and isolate S112
against S. aureus CSUR P1943 (MRSA, KTG, inducible MLSB), E. coli CSUR P4969 (coli R, HLP) and P. mirabilis CSUR P2049 (oxa-48).
Note de contenu : Annexes. Diplôme : Doctorat en sciences En ligne : ../theses/biologie/DJA7814.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11646 Biodiversité des actinomycètes halophiles et halotolérants isolés à partir de trois sites Ramsar situés au niveau de la Wilaya d’Oum El Bouaghi. [texte imprimé] / Chamss eddine Djaballah, Auteur ; Mahmoud Kitouni, Auteur . - 28/01/2021 . - جامعة الإخوة منتوري قسنطينة, 2021 . - 175 f. ; 30 cm.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Microbiologie: Ecologie Microbiennes biodiversité culturomics Streptomyces massilialgeriensis sp. nov. actinomycètes Ramsar écosystème extrême biodiversity Actinomycetes extreme ecosystem التنوع البيولوجي الأكتينوميسيت رامسار البيئة القاسية Index. décimale : 570 Sciences de la vie. Biologie Résumé :
This work represents a first study of the biodiversity of the actinomycetes inhabitants three Sebkhas protected by the Ramsar-Algeria convention. The physicochemical analyzes of the soil samples revealed extremely high salinities, basic or very basic pH, low percentages of moisture, moderate or very high percentages of organic matter. These results also showed that samples of sebkha Annk Djemel belong to the ""clay"" and ""Clay loam"" classes, samples of sebkha Guellif belong to the ""clay loam"" and ""sandy-clay loam"" classes and samples of sebkha Et Taref belong to the ""clay"" class. An isolation of actinomycetes from the soil has been achieved by the use of conventional methods and / or Culturomics. The enumeration results revealed that the number of actinomycetes could reach to
2.105 CFU/g of soil. Based on the enumeration results, a statistical analysis, carried out by the application of non-parametric tests of Kruskal-Wallis and Mann-Whitney, revealed that culture media relatively poor in nutrients and the concentration 5% of NaCl are the most favorable in the isolation of actinomycetes. The competitive effect of bacterial and fungal flora has also been highlighted. Following the isolation protocols adopted, we were able to purify and store a total of 204 isolates, all Gram (+), of which 108 isolates were derived from conventional isolation techniques and 96 isolates were obtained by the Culturomics method. Identification by the MALDITOF MS and sequencing of the 16S rDNA methods allowed us to identify a new species that we named Streptomyces massilialgeriensis sp. nov. and to assign certain other isolates to the genera Streptomyces, Nocardiopsis and Actinomyces. Other isolates have been identified as Bacillus, Virgibacillus, Gracilibacillus, Staphylococcus, Flavonifactor and Halobacillus. The activity test, carried out by the agar plug diffusion method, of 13 selected isolates belonging to the genera Streptomyces and Nocardiopsis against multidrug-resistant bacteria reveal interesting zones of inhibition of the isolate S20 against K. pneumoniae CSUR P1596 (coli R), E. coli CSUR P4969 (coli R, HLP), E. coli CSUR P5139 (carba R) and P. mirabilis CSUR P2049 (oxa-48), and isolate S112
against S. aureus CSUR P1943 (MRSA, KTG, inducible MLSB), E. coli CSUR P4969 (coli R, HLP) and P. mirabilis CSUR P2049 (oxa-48).
Note de contenu : Annexes. Diplôme : Doctorat en sciences En ligne : ../theses/biologie/DJA7814.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11646 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité DJA/7814 DJA/7814 Thèse Bibliothèque principale Thèses Disponible
Titre : Criblage des souches d’actinobactéries pour leurs pouvoirs PGPR : Essais in vitro et in planta sur Solanum lycopersicum L., Triticum durum Desf., et Daucus carota L. Type de document : texte imprimé Auteurs : Rihab Djebaili, Auteur ; Mahmoud Kitouni, Directeur de thèse ; Maddalena Del Gallo, Directeur de thèse Mention d'édition : 11-11-2021 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2021 Importance : 244 f. Format : 30 cm. Note générale : Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Microbiologie: Microbiologie générale et appliquée PGPB actinomycètes solubilisation du phosphate acide indole-3-acétique acide cyanhydrique biofertilisant ACC désaminase blé dur stress salin halotolérance la lutte biologique pathogènes SEM filtrats de culture tomate carotte actinomycetes phosphatesolubilization indole-3-acetic acid hydrocyanic acid biofertilizer ACC deaminase durum wheat salt stress halotolerance biological control pathogens culture filtrates tomato carrot Index. décimale : 570 Sciences de la vie. Biologie Résumé : Abiotic stress due to climate change and phytopathogens attacks lead to several damages in agricultural crops. Excessive use of chemicals in agriculture causes environmental pollution and loss of agricultural lands with fertile soils. Plant growth-promoting bacteria (PGPB) are an alternative strategy for sustainable agriculture. Among PGPBs, actinomycetes have recently gained increasing attention for their ability to alleviate plant stress and improve agricultural productivity. This study aimed to select actinomycetes strains with plant growth promoting traits, their plantroots association capacities, and their biostimulating effects without and with salt stress as well as the biocontrol power against several fungal and bacterial plant pathogens. The strains were studied for their phosphate solubilization capacity, indole-3-acetic acid (IAA), hydrocyanic acid (HCN),
and ammonia (NH3) production, and several enzymatic activities. Bacteria-root associations were studied by scanning electron microscopy (SEM), and a greenhouse experiment was performed to assess the inoculation effects on Solanum lycopersiumL.. Likewise, these strains were tested for in vitro halotolerant ability by several PGP tests with different salt concentrations (i.e., 0, 0.25, 0.5, 0.75, 1, 1.25, and 1.5 M NaCl) and by a greenhouse experiment on Triticum durum. The presence of 1-aminocyclopropane-1-carboxylate deaminase activity was also studied. Moreover, the strains were screened for their in vitro biocontrol activity by soluble and volatile compounds production against the fungal strains Fusarium oxysporum f. sp. radicis-lycopersici (FORL) and Rhizoctonia solani (RHS). The post-interaction events fungus-PGPB were analyzed by scanning electron microscopy. The antibacterial activity was evaluated against Pseudomonassyringae, Pseudomonas corrugata, Pseudomonas syringaepv. actinidiae, and Pectobacteriumcarotovorum subsp. carotovorum. Strains showing good in vitro biological control activities were studied for their antifungal and antibacterial activity using the cell culture filtrate (CFS). The consortium of potent strain was applied on Solanum lycopersicum L. and Daucus carota L. for in planta biocontrol activity. Among sixty actinomycetes, fourteen strains exhibited plant growth promoting characteristics. These strains were able to solubilize the phosphate, produce ammonia, and showed several enzymatic activities at different rates. The scanning electron microscopy revealed a good in vitro plant root association and colonization abilities. The actinomycetes inoculation influenced positively the tomato growth parameters. These strains exhibited important in vitro PGP traits under different salt concentrations. Most strains (86%) had 1-aminocyclopropane-1-carboxylate deaminase activity with significant amounts of ketobutyric acid. In the greenhouse experiment, inoculation with actinomycetes strainsimproved the durum wheat morpho-biochemical parameters, which recorded a significantly higher content of chlorophyll and proline than those of uninoculated controls both under normal and stressed conditions. Strains H12 (Streptomyces albidoflavus) and H14 (Nocardiopsisaegyptica) showed good in vitro antifungal activity with diffusible and volatile compounds (inhibition up to 85%) and antibacterial activity (diameter of inhibition> 10 mm). SEM micrographs showed morphological deterioration of the fungal filaments and changes in their structures. The CFS of potent strains was also active in fungal and bacterial pathogens inhibition (minimum inhibitory concentration up to 0.2%). The consortium was also able to alleviate the infection symptoms and allow a normal growth of the infected plants compared to the control. The obtained results demonstrate the efficacy of halotolerant actinomycetes strains as a biofertilizer and biocontrol agent for plant diseases management and for the alleviation of negative effects of salt stress in plants.
Note de contenu : Annexes.
Diplôme : Doctorat En ligne : ../theses/biologie/DJE7836.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11668 Criblage des souches d’actinobactéries pour leurs pouvoirs PGPR : Essais in vitro et in planta sur Solanum lycopersicum L., Triticum durum Desf., et Daucus carota L. [texte imprimé] / Rihab Djebaili, Auteur ; Mahmoud Kitouni, Directeur de thèse ; Maddalena Del Gallo, Directeur de thèse . - 11-11-2021 . - جامعة الإخوة منتوري قسنطينة, 2021 . - 244 f. ; 30 cm.
Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Microbiologie: Microbiologie générale et appliquée PGPB actinomycètes solubilisation du phosphate acide indole-3-acétique acide cyanhydrique biofertilisant ACC désaminase blé dur stress salin halotolérance la lutte biologique pathogènes SEM filtrats de culture tomate carotte actinomycetes phosphatesolubilization indole-3-acetic acid hydrocyanic acid biofertilizer ACC deaminase durum wheat salt stress halotolerance biological control pathogens culture filtrates tomato carrot Index. décimale : 570 Sciences de la vie. Biologie Résumé : Abiotic stress due to climate change and phytopathogens attacks lead to several damages in agricultural crops. Excessive use of chemicals in agriculture causes environmental pollution and loss of agricultural lands with fertile soils. Plant growth-promoting bacteria (PGPB) are an alternative strategy for sustainable agriculture. Among PGPBs, actinomycetes have recently gained increasing attention for their ability to alleviate plant stress and improve agricultural productivity. This study aimed to select actinomycetes strains with plant growth promoting traits, their plantroots association capacities, and their biostimulating effects without and with salt stress as well as the biocontrol power against several fungal and bacterial plant pathogens. The strains were studied for their phosphate solubilization capacity, indole-3-acetic acid (IAA), hydrocyanic acid (HCN),
and ammonia (NH3) production, and several enzymatic activities. Bacteria-root associations were studied by scanning electron microscopy (SEM), and a greenhouse experiment was performed to assess the inoculation effects on Solanum lycopersiumL.. Likewise, these strains were tested for in vitro halotolerant ability by several PGP tests with different salt concentrations (i.e., 0, 0.25, 0.5, 0.75, 1, 1.25, and 1.5 M NaCl) and by a greenhouse experiment on Triticum durum. The presence of 1-aminocyclopropane-1-carboxylate deaminase activity was also studied. Moreover, the strains were screened for their in vitro biocontrol activity by soluble and volatile compounds production against the fungal strains Fusarium oxysporum f. sp. radicis-lycopersici (FORL) and Rhizoctonia solani (RHS). The post-interaction events fungus-PGPB were analyzed by scanning electron microscopy. The antibacterial activity was evaluated against Pseudomonassyringae, Pseudomonas corrugata, Pseudomonas syringaepv. actinidiae, and Pectobacteriumcarotovorum subsp. carotovorum. Strains showing good in vitro biological control activities were studied for their antifungal and antibacterial activity using the cell culture filtrate (CFS). The consortium of potent strain was applied on Solanum lycopersicum L. and Daucus carota L. for in planta biocontrol activity. Among sixty actinomycetes, fourteen strains exhibited plant growth promoting characteristics. These strains were able to solubilize the phosphate, produce ammonia, and showed several enzymatic activities at different rates. The scanning electron microscopy revealed a good in vitro plant root association and colonization abilities. The actinomycetes inoculation influenced positively the tomato growth parameters. These strains exhibited important in vitro PGP traits under different salt concentrations. Most strains (86%) had 1-aminocyclopropane-1-carboxylate deaminase activity with significant amounts of ketobutyric acid. In the greenhouse experiment, inoculation with actinomycetes strainsimproved the durum wheat morpho-biochemical parameters, which recorded a significantly higher content of chlorophyll and proline than those of uninoculated controls both under normal and stressed conditions. Strains H12 (Streptomyces albidoflavus) and H14 (Nocardiopsisaegyptica) showed good in vitro antifungal activity with diffusible and volatile compounds (inhibition up to 85%) and antibacterial activity (diameter of inhibition> 10 mm). SEM micrographs showed morphological deterioration of the fungal filaments and changes in their structures. The CFS of potent strains was also active in fungal and bacterial pathogens inhibition (minimum inhibitory concentration up to 0.2%). The consortium was also able to alleviate the infection symptoms and allow a normal growth of the infected plants compared to the control. The obtained results demonstrate the efficacy of halotolerant actinomycetes strains as a biofertilizer and biocontrol agent for plant diseases management and for the alleviation of negative effects of salt stress in plants.
Note de contenu : Annexes.
Diplôme : Doctorat En ligne : ../theses/biologie/DJE7836.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11668 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité DJE/7836 DJE/7836 Thèse Bibliothèque principale Thèses Disponible
Titre : Etude de la biodiversité des bactéries actinomycétales dans les zones humides d’Ezzemoul, Djendli et Tinsilt par des approches culturales et moléculaires. Type de document : texte imprimé Auteurs : Maria Smati, Auteur ; Mahmoud Kitouni, Directeur de thèse Mention d'édition : 08-juil-20 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2020 Importance : 175 f. Format : 30 cm. Note générale : Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Microbiologie: Biotechnologies Microbiennes, Génomes et Environnement Biodiversité lacs salés actinobactéries halophiles actinobactéries halotolérantes métagénomique clonage biotechnologie Biodiversity saline lakes halophylic Actinobacteria halotolerant Actinobacteria metagenomics cloning biotechnology التنوع البيولوجي أكتينوبكتيريا محبة ومطيقة للملوحة البحيرات المالحة ميتاجنومكس استنساخ التكنولوجيا الحيوية Index. décimale : 570 Sciences de la vie. Biologie Résumé :
A combination of cultural and culture-independent (the latter is metagenomics by molecular cloning) techniques, was used to study the biodiversity of halophilic and halotolerant Actinobacteria, living in Ezzemoul sebkha, Chott Tinsilt and Djendli sebkha soils (located in northeastern Algeria). These ecosystems are mainly, extremely saline, alkaline, with low moisture content. According to the phylogenetic analysis of the 16S rDNA gene sequences: 40 isolates from the Ezzemoul site are assigned to species of the genera Nocardiopsis (dominant), Streptomyces and Rhodococcus; Another 42 isolates from the Tinsilt site are attributed to Streptomyces (dominant), Nocardiopsis, Actinopolyspora and Brevibacterium; and 22 isolates from the Djendli site belong to the same genera Streptomyces (dominant) and Nocardiopsis. Among all these isolates, there is a high probability of the presence of many new species. In addition, 24 clone sequences derived from the Ezzemoul site are affiliated with the genera Demequina (dominant), Plantactinospora, Friedmanniella and Mycobacterium. Also, 15 clone’s sequences from the Djendli site are related to the genera Marmoricola, Phytoactinopolyspora and Streptomyces; and to an unclassified actinobacterial clone. Some sequences (from both sites) are related to uncultured clones and/or not belonging to the class Actionbacteria (dominant in the site Djendli). Furthermore, the isolates obtained from the three study sites are: moderately halophilic and halotolerants, mesophilic, neutrophilic or acid-alkali-tolerant. Several of them can produce at the same time, extracellular hydrolytic enzymes such as cellulase, amylase, lipase, pectinase and proteases; as well as bioactive molecules against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and fungi (Candida albicans and Aspergillus niger). The results of this research show a wide taxonomic, physiological and metabolic diversity of Actinobacteria, from sebkhas and chott. These bacteria can therefore be excellent candidates for future biotechnological applications.
Note de contenu :
Annexes.Diplôme : Doctorat En ligne : ../theses/biologie/SMA7635.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11469 Etude de la biodiversité des bactéries actinomycétales dans les zones humides d’Ezzemoul, Djendli et Tinsilt par des approches culturales et moléculaires. [texte imprimé] / Maria Smati, Auteur ; Mahmoud Kitouni, Directeur de thèse . - 08-juil-20 . - جامعة الإخوة منتوري قسنطينة, 2020 . - 175 f. ; 30 cm.
Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Microbiologie: Biotechnologies Microbiennes, Génomes et Environnement Biodiversité lacs salés actinobactéries halophiles actinobactéries halotolérantes métagénomique clonage biotechnologie Biodiversity saline lakes halophylic Actinobacteria halotolerant Actinobacteria metagenomics cloning biotechnology التنوع البيولوجي أكتينوبكتيريا محبة ومطيقة للملوحة البحيرات المالحة ميتاجنومكس استنساخ التكنولوجيا الحيوية Index. décimale : 570 Sciences de la vie. Biologie Résumé :
A combination of cultural and culture-independent (the latter is metagenomics by molecular cloning) techniques, was used to study the biodiversity of halophilic and halotolerant Actinobacteria, living in Ezzemoul sebkha, Chott Tinsilt and Djendli sebkha soils (located in northeastern Algeria). These ecosystems are mainly, extremely saline, alkaline, with low moisture content. According to the phylogenetic analysis of the 16S rDNA gene sequences: 40 isolates from the Ezzemoul site are assigned to species of the genera Nocardiopsis (dominant), Streptomyces and Rhodococcus; Another 42 isolates from the Tinsilt site are attributed to Streptomyces (dominant), Nocardiopsis, Actinopolyspora and Brevibacterium; and 22 isolates from the Djendli site belong to the same genera Streptomyces (dominant) and Nocardiopsis. Among all these isolates, there is a high probability of the presence of many new species. In addition, 24 clone sequences derived from the Ezzemoul site are affiliated with the genera Demequina (dominant), Plantactinospora, Friedmanniella and Mycobacterium. Also, 15 clone’s sequences from the Djendli site are related to the genera Marmoricola, Phytoactinopolyspora and Streptomyces; and to an unclassified actinobacterial clone. Some sequences (from both sites) are related to uncultured clones and/or not belonging to the class Actionbacteria (dominant in the site Djendli). Furthermore, the isolates obtained from the three study sites are: moderately halophilic and halotolerants, mesophilic, neutrophilic or acid-alkali-tolerant. Several of them can produce at the same time, extracellular hydrolytic enzymes such as cellulase, amylase, lipase, pectinase and proteases; as well as bioactive molecules against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and fungi (Candida albicans and Aspergillus niger). The results of this research show a wide taxonomic, physiological and metabolic diversity of Actinobacteria, from sebkhas and chott. These bacteria can therefore be excellent candidates for future biotechnological applications.
Note de contenu :
Annexes.Diplôme : Doctorat En ligne : ../theses/biologie/SMA7635.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11469 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité SMA/7635 SMA/7635 Thèse Bibliothèque principale Thèses Disponible
Titre : Isolement, identification et criblage d’actinomycètes à activité chitinolytique à partir du sol de la région de Laghouat. : Optimisation de la production de chitinase par Streptomyces griseorubens C9 par la méthode des surfaces de réponse Type de document : texte imprimé Auteurs : Meriem Gasmi, Auteur ; Mahmoud Kitouni, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2017 Importance : 142 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Actinomycètes BOX-PCR ARNr 16S chitinases Streptomyces griseorubens C9 Plackett-Burman Box-Wilson purification Actinomycetes 16S rRNA الأكتنوميسات الكيتناز المكافحة الحيوية Index. décimale : 570 Sciences de la vie. Biologie Résumé : With at least 10 gigatons synthesized and degraded each year in the biosphere, chitin is the second
most represented polysaccharide in nature after cellulose. It is a crystalline polysaccharide consisting
of long linear chains containing more than 1000 units of N-acetyl-β-D-glucosamine linked by β-1,4
glycoside bonds. Chitin degradation is performed by chitinases (E.C. 3.2.1.14), that hydrolyze ß-1,4
bonds releasing compounds easily metabolized by many microbes. Production of microbial chitinases
receives worldwide attention in both industrial and scientific communities, because of its wide
applications spectrum. Chitinases are used in biochemistry, food processing, and various chemical
industries due their antimicrobial, anticholesterol, and antitumor activities. They are also used in
waste-water treatment, dietary fiber and in agriculture to inhibit plant pathogens. The physiological
function of chitinases depends on their origin. In bacteria, chitinases play a trophic role by degrading
chitin, as source of both carbon and nitrogen. Microorganisms particularly Streptomyces are efficient
chitin hydrolysers. Chitinases have been identified in several Streptomyces spp. It is induced by chitin
and repressed by readily utilizable carbon sources such as N-acetyl-glucosamine and glucose. In this
thesis, we chose to study actinobacteria isolated from a semi-arid soil of the Algerian desert in order to
identify strains with a high chitinolytic and antifungal potential. We isolated 40 phenotypically
different actinobacteria. First, we carried out a functional study by screening these isolates on a
minimal medium supplemented with colloidal chitin (CCM) to characterize their chitinolytic activities
under extreme temperature conditions (30, 35, 40, 45 and 50 °C) and pH (5, 7 and 9). In addition, a
taxonomic study was conducted by combining a BOX-PCR approach and sequencing 16S rRNA of 20
strains. This identification showed that 10 of these isolates belonged to the genus of Streptomyces, two
to the genus of Micromonospora and 08 potential new bacterial species. Also, the search for
antimicrobial activity against 06 test bacteria and two phytopathogenic fungi was carried out, using a
novel glucose-inducing / repressing chitinase approach in the antifungal test, to prove that only
chitinases can inhibit these phytopathogenic fungi. One strain (C31) was able to reduce fungal growth
only after induction of chitinase by colloidal chitin. The second part of this work aimed to use
statistical Plackett–Burman and Box–Wilson response surface methodology to optimize the medium
components and, thus, improve chitinase production by Streptomyces griseorubens C9. First, syrup of
date, colloidal chitin, yeast extract and K2HPO4, KH2PO4 were proved to have significant effects on
chitinase activity using the Plackett–Burman design. Then, an optimal medium was obtained by a
Box–Wilson factorial design of response surface methodology in liquid culture. Maximum chitinase
production (0.902 U / ml) was predicted in medium containing 2% colloidal chitin, 0.47% syrup of
date, 0.25 g/l yeast extract and 1.81 g/l K2HPO4, KH2PO4.This was confirmed by Erlenmeyer cultures
where the Production of chitinase by S. griseorubens C9 reached 1.53 U/ml, the yield of enzyme
production was increased 26.38% after optimization by the response surface methodology. Finally,
purification and partial characterization of the enzyme produced in the optimized medium was
performed. 3 major purification steps were done and the enzyme reached a purification fold of 23.24; a
yield of 29.7% and a specific activity equal to 2.393 U/mg. The purified chitinase activity had
optimum catalytic activity at pH 5.0 and 50 °C. It retained more than 60% stability at pH range
between 4.0 and 7.0 and remained stable at temperatures between 30 °C and 60 °C. Thus, S.
griseorubens C9 could be a potent strain for industrial chitinase production, as well as in
biotechnology and bio-control fields.Diplôme : Doctorat En ligne : ../theses/biologie/GAS7119.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10482 Isolement, identification et criblage d’actinomycètes à activité chitinolytique à partir du sol de la région de Laghouat. : Optimisation de la production de chitinase par Streptomyces griseorubens C9 par la méthode des surfaces de réponse [texte imprimé] / Meriem Gasmi, Auteur ; Mahmoud Kitouni, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2017 . - 142 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Actinomycètes BOX-PCR ARNr 16S chitinases Streptomyces griseorubens C9 Plackett-Burman Box-Wilson purification Actinomycetes 16S rRNA الأكتنوميسات الكيتناز المكافحة الحيوية Index. décimale : 570 Sciences de la vie. Biologie Résumé : With at least 10 gigatons synthesized and degraded each year in the biosphere, chitin is the second
most represented polysaccharide in nature after cellulose. It is a crystalline polysaccharide consisting
of long linear chains containing more than 1000 units of N-acetyl-β-D-glucosamine linked by β-1,4
glycoside bonds. Chitin degradation is performed by chitinases (E.C. 3.2.1.14), that hydrolyze ß-1,4
bonds releasing compounds easily metabolized by many microbes. Production of microbial chitinases
receives worldwide attention in both industrial and scientific communities, because of its wide
applications spectrum. Chitinases are used in biochemistry, food processing, and various chemical
industries due their antimicrobial, anticholesterol, and antitumor activities. They are also used in
waste-water treatment, dietary fiber and in agriculture to inhibit plant pathogens. The physiological
function of chitinases depends on their origin. In bacteria, chitinases play a trophic role by degrading
chitin, as source of both carbon and nitrogen. Microorganisms particularly Streptomyces are efficient
chitin hydrolysers. Chitinases have been identified in several Streptomyces spp. It is induced by chitin
and repressed by readily utilizable carbon sources such as N-acetyl-glucosamine and glucose. In this
thesis, we chose to study actinobacteria isolated from a semi-arid soil of the Algerian desert in order to
identify strains with a high chitinolytic and antifungal potential. We isolated 40 phenotypically
different actinobacteria. First, we carried out a functional study by screening these isolates on a
minimal medium supplemented with colloidal chitin (CCM) to characterize their chitinolytic activities
under extreme temperature conditions (30, 35, 40, 45 and 50 °C) and pH (5, 7 and 9). In addition, a
taxonomic study was conducted by combining a BOX-PCR approach and sequencing 16S rRNA of 20
strains. This identification showed that 10 of these isolates belonged to the genus of Streptomyces, two
to the genus of Micromonospora and 08 potential new bacterial species. Also, the search for
antimicrobial activity against 06 test bacteria and two phytopathogenic fungi was carried out, using a
novel glucose-inducing / repressing chitinase approach in the antifungal test, to prove that only
chitinases can inhibit these phytopathogenic fungi. One strain (C31) was able to reduce fungal growth
only after induction of chitinase by colloidal chitin. The second part of this work aimed to use
statistical Plackett–Burman and Box–Wilson response surface methodology to optimize the medium
components and, thus, improve chitinase production by Streptomyces griseorubens C9. First, syrup of
date, colloidal chitin, yeast extract and K2HPO4, KH2PO4 were proved to have significant effects on
chitinase activity using the Plackett–Burman design. Then, an optimal medium was obtained by a
Box–Wilson factorial design of response surface methodology in liquid culture. Maximum chitinase
production (0.902 U / ml) was predicted in medium containing 2% colloidal chitin, 0.47% syrup of
date, 0.25 g/l yeast extract and 1.81 g/l K2HPO4, KH2PO4.This was confirmed by Erlenmeyer cultures
where the Production of chitinase by S. griseorubens C9 reached 1.53 U/ml, the yield of enzyme
production was increased 26.38% after optimization by the response surface methodology. Finally,
purification and partial characterization of the enzyme produced in the optimized medium was
performed. 3 major purification steps were done and the enzyme reached a purification fold of 23.24; a
yield of 29.7% and a specific activity equal to 2.393 U/mg. The purified chitinase activity had
optimum catalytic activity at pH 5.0 and 50 °C. It retained more than 60% stability at pH range
between 4.0 and 7.0 and remained stable at temperatures between 30 °C and 60 °C. Thus, S.
griseorubens C9 could be a potent strain for industrial chitinase production, as well as in
biotechnology and bio-control fields.Diplôme : Doctorat En ligne : ../theses/biologie/GAS7119.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10482 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité GAS/7119 GAS/7119 Thèse Bibliothèque principale Thèses Disponible
Titre : Mise au point de la production d'acide lactique par lactobacillus delbruechi subsp , bulgaricus à partir de lactoserum Type de document : texte imprimé Auteurs : Mahmoud Kitouni, Auteur ; Univ. de Constantine, Éditeur scientifique ; J.P. Larpent, Directeur de thèse Année de publication : 1995 Importance : 116 f. Note générale : 01 Disponible salle de recherche
02 Disponibles au magasin de la bibliothèque centraleLangues : Français (fre) Catégories : Français - Anglais
BiologieTags : Acide lactique Lactoseum Index. décimale : 570 Sciences de la vie. Biologie Diplôme : Magistère Permalink : index.php?lvl=notice_display&id=1652 Mise au point de la production d'acide lactique par lactobacillus delbruechi subsp , bulgaricus à partir de lactoserum [texte imprimé] / Mahmoud Kitouni, Auteur ; Univ. de Constantine, Éditeur scientifique ; J.P. Larpent, Directeur de thèse . - 1995 . - 116 f.
01 Disponible salle de recherche
02 Disponibles au magasin de la bibliothèque centrale
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Acide lactique Lactoseum Index. décimale : 570 Sciences de la vie. Biologie Diplôme : Magistère Permalink : index.php?lvl=notice_display&id=1652 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité KIT/2622 KIT/2622 Thèse Bibliothèque principale Thèses Disponible
