Publications Scientifiques
Permanent URI for this communityhttps://dspace.univ-boumerdes.dz/handle/123456789/10
Browse
59 results
Search Results
Item Chitosan nanoparticles with controlled size and zeta potential(John Wiley and Sons Inc, 2023) Benamer-Oudih, Samah; Tahtat, Djamel; Nacer Khodja, Assia; Mahlous, Mohamed; Hammache, Yasmina; Guittoum, Abd-Errahim; Kebbouche-Gana, SalimaOptimization of chitosan nanoparticles (ChNs) production process employing a 2(5–2) fractional factorial design was performed to analyze the influence of viscosity average molecular weight (40–120 kDa), the initial concentration of chitosan (2–5 g/L), the initial tripolyphosphate (TPP) concentration (0.8–1.2 g/L), the ratio chitosan/TPP (4/1–10/1) (V/V), and the stirring speed (300–700 rpm), on final nanoparticles size and zeta potential. The measured responses of average particle size and surface charge were determined on Zetasizer Nano ZS. ChNs were prepared using ionotropic cross-linking of chitosan and TPP and were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and differential scanning calorimetry (DSC). The experiments showed that the size of synthesized nanoparticles depended on initial concentration and molecular weight of chitosan, TPP concentration and stirring speed within the chosen levels. However, the zeta potential was significantly influenced by chitosan molecular weight, chitosan concentration and stirring speed. The FTIR analysis confirmed the interaction between negative charge of TPP with positive charge of chitosan through the appearance of new peaks at 1222 and 895 cm−1 in produced ChNs. XRD and DSC analysis were used to evaluate the effect of crosslinking of chitosan on crystal structure of ChNsItem Electrocatalytic activity survey of some cathode materials for the reduction of nitrites and nitrates in aqueous solution(Publishing House of the Romanian Academy, 2020) Angar, Yassmina; Daoudi, Sofiane; Kebbouche-Gana, Salima; Djelali, Nacer-EddineThe electrochemical techniques are the subject of increasing interest on the environmental remediation methods thanks to their efficiency and their selectivity. It was classified among the cleanest methods because it does not produce sludge and undesirable intermediate byproducts. For these reasons, we have chosen this technology for the reduction of nitrites and nitrates ions from aqueous solutions. The objective of our study is the comparison of several cathodes materials performances, in order to promote an optimal electro-reduction of these ions. Indeed, we have used the copper, graphite, stainless steel and zinc as cathodes; among them, we have selected the most efficient on which we have optimized the operational conditions. The results suggested that the copper cathode was the most efficient for the reduction of both tested ions compared to the other tested materials. Therefore, the optimization of operational conditions allows us to fixed them at: scan rate=50 mV/s, initial effluent concentration=100 mg/L, pH=7 and potential range of the cyclic voltammetry scanning of [-1,+1]V/SCE for both ions. Under these optimal parameters, the reduction yield after 45min was important that can achieve 96.5% and 99% for nitrites and nitrates respectivelyItem Identification and phylogenetic analyses of anaerobic sulfidogenic bacteria in two Algerian oilfield water injection samples(Taylor & Francis, 2021) Lenchi, Nesrine; Kebbouche-Gana, Salima; Servais, Pierre; Gana, Mohammed Lamine; Llirós, MarcCorrosion of metallic oilfield pipelines by microorganisms is a costly but poorly understood phenomenon. For the first time, sulfidogenic communities in injection waters of two Algerian oilfields, Tin Fuin Tabankort (IT3) and Stah (IS2) were examined using the 16S rRNA gene cloning and sequencing approach. Water samples were inoculated into selective medium for sulfate-reducing bacteria and incubated under anaerobic conditions at 45 °C. The total number of culturable sulfidogenic microorganisms in the samples obtained from the two sampled waters (IT3 and IS2) was 2.4 × 105 cells/mL and 3.9 × 104 cells/mL, respectively. Scanning electron microscopy analyses showed different morphological forms reflecting the diversity of sulfidogenic communities. 16S rRNA gene sequencing and phylogenetic diversity analyses revealed that both water reservoirs harbor large amounts of anaerobic bacteria. However, a majority of all the sequences analyzed (e.g., 34% in the IS2 and 84% in the IT3 samples) were not assigned to any known bacterial group, suggesting that subsurface waters harbor very large sulfidogenic anaerobic microbial communities of as yet undescribed bacterial phyla. Proteobacteria were found to be the most dominant phylum in the IS2 sample (49%); however, no Proteobacteria were detected at the IT3 production well. The Firmicutes phylum (10%) was detected in the two water samples, whereas Bacteroidetes phylum (7%) was retrieved only in IT3. The most abundant related genera were: Desulfotomaculum, Porphyrobacter, Hyphomicrobium, Acidocella, Comamonas, Ramlibacter, Pseudomonas, Enterobacter and Flavitalea. No shared operational taxonomic units were observed among the two samples analyzed, demonstrating the uniqueness of each subsurface water well. This study demonstrates the diversity of the sulfidogenic bacteria that might play a critical role in the souring mediated corrosion of metallic oilfield pipelines. This information could help oilfield companies develop better anticorrosion treatments and strategiesItem A Comprehensive Study on Crude Methanolic Extract of Daphne gnidium L. as Effective Corrosion Inhibitors of Mild Steel Induced by SRB Consortium(Springer, 2019) Djouahra-Fahem, Djamila; Angar, Yassmina; Lamine Mohamed, Gana; Khoukhi, Faiza; Kebbouche-Gana, SalimaThe aim of the present work is the evaluation of effect of methanolic extract obtained from Daphne gnidium against biocorrosion caused by sulphate-reducing bacteria (SRB). Herein, the study of the influence of SRB consortium has been realized on the biological and electrochemical properties of the carbon steel API5LX60 immersed in water sample obtained from an Algerian oil field separator. The monitoring of the treatment effects on the SRB performance using kits test and weight loss methods showed a positive effect of the methanolic extract of D. gnidium as a corrosion inhibitor at a concentration of 0.8 g/L. In the other hand, the weight loss test has generated an efficiency rate of 95.99% at a concentration of 1.6 g/L. A linear polarization resistance approved these results, and they have given a yield of 91.14% with a polarization resistance value of 28.9 kΩ cm2 at a concentration of 0.25 g/L.Item Efficiency Evaluation of Anti-corrosion Treatment of Carbon Steel by Extracts of Red Algae Collected from Mediterranean Coast(Revista de Chimie SRL, 2021) Khoukhi, Faiza; Kebbouche-Gana, Salima; Djelali, Nacer Eddine; Gana, Mohamed LamineThe paper presents the assessment of inhibition effectiveness of biomolecules extracted from red seaweed against biocorrosion in the petroleum industry. The first objective of this study was to obtain extracts (A, B and C, prepared respectively from red algae species: Corallina ellongata, Gymnogongrus crenulatus and Pterocladia capillacea) by ethanol extraction method. The infrared spectra of the three extracts confirmed the presence of amine derivatives molecules known by their anti-corrosion inhibiting powers. The second objective was based on the identification of physico-chemical characteristics of the extracts and thus revealing their inhibitory and / or bactericidal power in bacterial corrosion of carbon steel in injection water contaminated with sulfato-reducing bacteria. Biological test of all extracts gave a concentration upto 10 germs/mL in contaminated water by sulfato-reducing bacteria during 28 days of incubation at 37°C. Evolution in time of the open-circuit potential showed a longer incubation time for electrolyte with extracts, whereas the stabilization time was shorter. Current corrosion density, polarization resistance, charge transfer resistance and double layer capacity were determined by using linear polarizarion resistance technique and electrochemical impedance spectroscopy. The corrosion protection efficiency of extract obtained from Gymnogongrus crenulatus (extract B) reached a maximum protective capacity of 99.69% at 5 ppm in the injection water.Item Biodegradation of Petroleum hydrocarbons and Biosurfactant production by an extremely halophilic Archaea Halovivax sp. A21(Aljest, 2017) Khemili-Talbi, S.; Kebbouche-Gana, Salima; Akmoussi-Toumi, S.; Gana, M.L.; Lahiani,S.; Ferrioune ,I.; Angar,Y.Over the recent few years, biosurfactant has played an important role in the industrial application especially in oil recovery; even in high salinity conditions. The potential of biosurfactant production by the extreme halophilic archaeon Halovivax sp. A21 in the presence of petroleum hydrocarbons (2% v/v) as sole carbon source at high salinity (25% NaCl) has been investigated. The results show the ability of Halovivax sp. A21 to grow and reduce surface tension under an optimum range of pH (7-9), salinities (15-35% NaCl) and temperature (40-45°C) for an optimized volume of 100 ml of the medium for 1000 ml capacity Erlenmeyer flasks with an optimum agitation of 120 rpm. The rates of biosurfactant production on petroleum hydrocarbons were enhanced with increasing NaCl concentration in the medium with an optimum of 25%. Biosurfactant production by Halovivax sp. A21 showed high emulsifying activity (more than 80%) and decreased surface tension (24.5 mN/m). The stability of the produced biosurfactant was determined by different physico-chemical conditions like pH, temperature and salinity. Moreover, the partial purification of the derived biosurfactant by silica gel column chromatography and Thin-layer chromatography revealed that it belongs to the lipopeptide group. Although both catechol dioxygenases participated in the degradation of petroleum hydrocarbons, more induction of catechol 1,2 dioxygenase was observed than the catechol 2,3 dioxygenase which indicated the predominance of the ortho cleavage pathways in the petroleum hydrocarbons degradation by the halophilic strain Halovivax sp. A21. The results demonstrated that strain Halovivax sp. A21 was able to increase the bioavailability of insoluble hydrocarbons, thus facilitating their uptake and their biodegradation even at high salt concentration. Likewise, the search of novel biosurfactants in extremophiles, or the use of microorganisms that present excellentItem Insights into the draft genome sequence of bioactives-producing Bacillus thuringiensis DNG9 isolated from Algerian soil-oil slough(2018) Daas, Mohamed Seghir; Rosana, Albert Remus R.; Acedo, Jeella Z.; Douzane, Malika; Nateche, Farida; Kebbouche-Gana, Salima; Vederas, John C.Bacillus thuringiensisis widely used as a bioinsecticide due to its ability to form parasporal crystals containingproteinaceous toxins. It is a member of theBacillus cereussensulato, a group with low genetic diversity butproduces several promising antimicrobial compounds.B. thuringiensisDNG9, isolated from an oil-contaminatedslough in Algeria, has strong antibacterial, antifungal and biosurfactant properties. Here, we report the 6.06 Mbpdraft genome sequence ofB. thuringiensisDNG9. The genome encodes several gene inventories for thebiosynthesis of bioactive compounds such as zwittermycin A, petrobactin, insecticidal toxins, polyhydroxyalkanoatesand multiple bacteriocins. We expect the genome information of strain DNG9 will provide another model system tostudy pathogenicity against insect pests, plant diseases, and antimicrobial compound mining and comparativephylogenesis among theBacillus cereussensulatogroupItem Valorization of olive tree leaves : phytochemical and pharmacological characterizations, selection of extracts and formulation of herbal cream(2021) Bakdi, Hadjer; Kebbouche-Gana, Salima; Djelali, N.; Louhab, K.; Yahiaoui, K.Olive tree (Olea EuropeaL.) is one of the most important crops in the Mediterranean countries. The global olive oil industry annually generates many tons of olive leaves as waste.The present study aims at a valorisation of Algerian olive leaves harvested from the region of Bouirafor therapeutic use. In order to evaluate the biological effects of the wild olive tree, chemical characterization tests of the leaves were carried out in the Natural Substances Laboratory of Saidal group according to their validated protocols drawn from the French pharmacopoeia. A phytochemical screening has been realized and whose purpose is to refer to the extraction, screening and identification of the medicinally active substances in the plant. Different extractions have been carried out in several solvents in order to extract bioactive molecules from the leaves using several solvents. Subsequently, a pharmacological characterization has been completed by determining the following: antioxidant activity of the extracts was evaluated in vitro by the DPPH method, anti-inflammatory activity was studied in vivo by induction of carrageenan oedema; the antibacterial activity was achieved by the agar medium diffusion method. Finally, we formulated an anti-inflammatory and antibacterial ointments based on the results obtainedItem Biosurfactant production from newly isolated Rhodotorula sp.YBR and its great potential in enhanced removal of hydrocarbons from contaminated soils(Springer, 2021) Derguine-Mecheri, Louiza; Kebbouche-Gana, Salima; Djenane, DjamelOne of the very promising methods in the field of bioremediation of hydrocarbons is the application of biosurfactant- producing microorganisms based on the use of wastewater as renewable substrates of culture media, contributing to the reduction of costs. With this aim, the production, characterization and properties of the yeast strain YBR producing a biosurfactant newly isolated from an oilfield in Algeria, using wastewater from olive oil mills (OOMW) as a substrate for a low-cost and effective production, have been investigated. Screening of biosurfactant production was carried out with different tests, including emulsification index test (E24), drop collapse test, oil spreading technique and measurement of surface tension (ST). The isolated yeast strain was found to be a potent biosurfactant producer with E24 = 69% and a significant reduction in ST from 72 to 35 mN m-1. The study of the cultural, biochemical, physiological and genetic characteristics of the isolate allowed us to identify it as Rhodotorula sp. strain YBR. Fermentation was carried out in a 2.5 L Minifors Bioreactor using crude OOMW as culture medium, the E24 value reached 90% and a reduction of 72 to 35 mN m-1 in ST. A biosurfactant yield = 10.08 ± 0.38 g L-1 was recorded. The characterization by semi-purification and thin layer chromatography (TLC) of the crude extract of biosurfactant showed the presence of peptides, carbohydrates and lipids in its structure. The crude biosurfactant exhibited interesting properties such as: low critical micellar concentration (CMC), significant reduction in ST and strong emulsifying activity. In addition, it has shown stability over a wide range of pH (2-12), temperature (4-100 °C) and salinity (1-10%). More interestingly, the produced biosurfactant has proven to be of great potential application in the remobilization of hydrocarbons from polluted soil with a removal rate of greater than 95%Item Microbacterium algeriense sp. nov., a novel actinobacterium isolated from Algerian oil production waters(Microbiology Society, 2020) Lenchi, Nesrine; Anzil, Adriana; Servais, Pierre; Kebbouche-Gana, Salima; Gana, Mohamed LamineA non-motile, straight-rod-shaped, Gram-stain-positive and facultative anaerobic bacterium (i.e., strain G1T) was isolated from production waters from an Algerian oilfield. Growth was observed in the presence of 0.3-3.5 % (w/v) NaCl, at 20-50 °C and at pH 6.0-9.0. Results of phylogenetic analyses based on 16S rRNA gene sequences showed that strain G1T belonged to the genus Microbacterium. Strain G1 T was closely related to Microbacterium oxydans (DSM 20578T) and Microbacterium maritypicum (DSM 12512T) with 99.8 % sequence similarity and to Microbacterium saperdae (DSM 20169T) with 99.6 % sequence similarity. Strain G1 T contained MK9, MK10, MK11, MK12 and MK13 as respiratory quinones, and phosphatidylglycerol, diphosphatidylglycerol and glycolipid as the major polar lipids. The major cellular fatty acids were anteiso-C15:0, iso-C16:0 and anteiso-C17:0. The estimated DNA G+C content was 69.57 mol% based on its draft genome sequence. Genome annotation of strain G1T predicted the presence of 3511 genes, of which 3483 were protein-coding and 47 were tRNA genes. The DNA-DNA hybridization (DDH) and average nucleotide identity (ANI) values between strain G1T and M. oxydans (DSM 20578T) and M. maritypicum (DSM 12512T) were in both cases far below the respective species boundary thresholds (27.5 and 28.0 % for DDH; and 84.40 and 84.82% for ANI, respectively). Based on the data presented above, strain G1T was considered to represent a novel species for which the name Microbacterium algeriense is proposed with the type strain G1T (=DSM 109018T=LMG 31276T)