Publications Scientifiques

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Author: search.filters.author.Akmoussi-Toumi, Siham

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    Diversity of Culturable Halophilic Archaea and Bacteria from Chott Tinsilt and El Malah Salt-Lake in Algeria
    (Science publications, 2020) Akmoussi-Toumi, Siham; Khemili-Talbi, Souad; Kebbouche-Gana, Salima; Lenchi-Izouine, Nesrine; Khelfaoui, Mohamed El Amine; Sayah, Amna; Bouarab, Ghania; Ferrioune, Imen; Mokhtari, Wafa; Najjari, Afef
    At the limits of life, hyper-saline aquatic ecosystems; Chott and Sebkha are a model of choice of extreme environments, housing a halophilic microflora that had to adapt to these conditions. In Algeria, these ecosystems are poorly studied. However, our study was carried out on the waters of Chott Tinsilt and Sebkha El Malah. The study of this microflora revealed the presence of a significant morphological, physiological and metabolic diversity. The molecular study allowed us to access to a phylogenetic affiliation including an Archean Species (ATS1) and 7 bacterial species (A1, A2, A3, A4, B1, B4, B5). The results showed that these isolates were related to the genera Haloferax (for the strain ATS1) and Halomonas (strains A1, A2 and A4), Staphylococcus (strain A3), Salinivibrio (strain B1), Planococcus (strain B4) and Halobacillus (strain B5). Most isolates produced hydrolases at high salt concentrations. The Production yields obtained are very promising for applications in the biotechnology and industrial microbiology.
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    Diversity of culturable halophilic archaea and bacteria from chott tinsilt and el malah salt-lake in Algeria
    (Current Research in Bioinformatics, 2020) Akmoussi-Toumi, Siham; Khemili-Talbi, Souad; Kebbouche-Gana, Salima
    At the limits of life, hyper-saline aquatic ecosystems; Chott and Sebkha are a model of choice of extreme environments, housing a halophilic microflora that had to adapt to these conditions. In Algeria, these cosystems are poorly studied. However, our study was carried out on the waters of Chott Tinsilt and Sebkha El Malah. The study of this microflora revealed the presence of a significant morphological, physiological and metabolic diversity. The molecular study allowed us to access to a phylogenetic affiliation including an Archean Species (ATS1) and 7 bacterial species (A1, A2, A3, A4, B1, B4, B5). The results showed that these isolates were related to the genera Haloferax (for the strain ATS1) and Halomonas (strains A1, A2 and A4), Staphylococcus (strain A3), Salinivibrio (strain B1), Planococcus (strain B4) and Halobacillus (strain B5). Most isolates produced ydrolases at high salt concentrations. The Production yields obtained are very promising for pplications in the biotechnology and industrial microbiology.
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    Purification and characterization of an organic solvent-tolerant and detergent-stable lipase from Haloferax mediterranei CNCMM 50101
    (Elsevier, 2018) Akmoussi-Toumi, Siham; Khemili-Talbi, Souad; Ferioune, Imen; Kebbouche-Gana, Salima
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    Production of an extracellular lipase from a halophilic isolate, Idiomarina sp.
    (2013) Akmoussi-Toumi, Siham; Kebbouche-Gana, Salima; Lenchi, Nesrine
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    Valorisation de sous produits agroalimentaires pour la production de biosurfactants
    (2014) Kebbouche-Gana, Salima; Khemili, Souad; Akmoussi-Toumi, Siham; Lenchi, Nesrine
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    Isolation of an extremely halophilic arhaeon Natrialba sp. C21 able to degrade aromatic compounds and to produce stable biosurfactant at high salinity
    (Springer, 2015) Khemili-Talbi, S.; Kebbouche-Gana, Salima; Akmoussi-Toumi, Siham; Angar, Yassmina; Gana, M.L
    Natrialba sp. strain C21 was isolated from oil contaminated saline water in Ain Salah (Algeria) and has exhibited a good potential for degrading phenol (3 % v/v), naphthalene (3 % v/v), and pyrene (3 % v/v) at high salinity with high growth, enzymatic activity and biosurfactant production. Successful metabolism of aromatic hydrocarbon compounds of the strain Natrialba sp. C21 appears to require the ortho-cleavage pathway. Indeed, assays of the key enzymes involved in the ring cleavage of catechol 1, 2-dioxygenase indicated that degradation of the phenol, naphthalene and pyrene by strain Natrialba sp. C21 was via the ortho-cleavage pathway. Cells grown on aromatic hydrocarbons displayed greater ortho-activities mainly towards catechol, while the meta-activity was very low. Besides, biosurfactants derived from the strain C21 were capable of effectively emulsifying both aromatic and aliphatic hydrocarbons and seem to be particularly promising since they have particular adaptations like the increased stability at high temperature and salinity conditions. This study clearly demonstrates for the first time that strain belonging to the genera Natrialba is able to grow at 25 % (w/v) NaCl, utilizing phenol, naphthalene, and pyrene as the sole carbon sources. The results suggest that the isolated halophilic archaeon could be a good candidate for the remediation process in extreme environments polluted by aromatic hydrocarbons. Moreover, the produced biosurfactant offers a multitude of interesting potential applications in various fields of biotechnology. © 2015 Springer Japan
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    Production of biosurfactant on crude date syrup under saline conditions by entrapped cells of Natrialba sp. strain E21, an extremely halophilic bacterium isolated from a solar saltern (Ain Salah, Algeria)
    (Springer, 2013) Kebbouche-Gana, Salima; Gana, Mohamed Lamine; Ferrioune, Imen; Khemili, Souad; Lenchi, Nesrine; Akmoussi-Toumi, Siham; Bouanane-Darenfed, Nabila Amel; Djelali, Nacer-Eddine
    A bacterial strain E21 was isolated from a sample of water collected in the salt lake located close to Ain Salah, Algeria. The analysis of 16S rRNA gene sequence had indicated that the strain had 93 % sequence similarity with the genus Natrialba sp. strain E21 (Gen- Bank, FR750525.1) and was considered extremely halo- philic. Production of biosurfactant by the strain E21 with free and entrapped cells was investigated using soluble starch in the saline conditions. Biosurfactant synthesis was followed by measuring the surface tension and emulsifying index 9 days under optimal conditions (40 C, pH 7). Some diffusional limitations in alginate and agar beads affected the kinetics of biosurfactant production when compared to that obtained with free cells culture. The minimum values of surface tension were 27 and 30 mN m - 1 achieved after 9 days with free and immobilized cells, respectively, while the corresponding maximum E24 values were 65.3 and 62.3 %, respectively. The re-use of bacterial cells along with the limited cell losses provided by the immobilized system might lead to significant reduction of the biosur- factant production cost