Communications scientifiques internationales

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Browsing Communications scientifiques internationales by Author "Abdi, Nadia"

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    PRELIMINARY STUDY ON THE EFFECT OF LOW ELECTRIC CURRENT ON PRODUCTION OF BIOSURFACTANT BY Pseudomonas aeruginosa
    (2019-09-18) Tazdaït, Djaber; Salah, Rym; Guiddir, Fadila; Temouche, Nawal; Abdi, Nadia; Grib, Hocine; Mameri, Nabil
    Several studies have been attempted to investigate the effect of different parameters on the performance of biosurfactant production by microorganisms, these parameters include temperature, pH, agitation, and carbon and nitrogen sources. In literature, the studies devoted to the use of electric current are mostly focused on the treatment of wastewaters by electrocoagulation. However, to the best of our knowledge, no studies have been reported on the direct effect of electric current on microbial production of biosurfactants. The main purpose of this study was to investigate the effect of direct electric current on the performance of a biosurfactant-producing strain Pseudomonas aeruginosa, isolated from hydrocarbon-contaminated soil, to produce biosurfactant under aerobic conditions. The bacterial strain used in this study was previously isolated from a fuel-contaminated soil collected from a gas station located in Boumerdès, Algeria. The effect of direct electric current on the biosurfactant production was evaluated by varying the inter-electrode distance (d) (2, 4 and 6cm) with current density values (D) of 3µA/cm2 for 3 days at room temperature (21.7°C ± 3.07°C), at 150 rpm and pH 7. Besides, control experiment was carried-out under the same conditions for which no electrical treatment was performed. On the other hand, the biosurfactant concentration was determined at the end of each experiment using a solvent extraction method. The results clearly showed that direct current application with distance between electrodes of 2 cm yielded the highest biosurfactant production, and emulsification index (E24). Besides, the production cost decreases of about 20% with electric current application, which contributes very slightly in the total energy consumption cost. This method might, in the future, lead the way towards profitable application in enhancing biosurfactant production.
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    THE USE OF NEW LOW-COST SUBSTRATES FOR BIOSURFACTANT PRODUCTION
    (2019-09-18) Salah-Tazdaït, Rym; Tazdaït, Djaber; Delhoum, Djura; Mouffok, Samia; Kabouche, Fatma; Keddou, Imene; Abdi, Nadia; Grib, Hocine; Mameri, Nabil
    In literature, several carbon sources were used for biosurfactant production. Most of these studies are focused on the use of conventional carbon sources such as glucose, fructose, pyruvate, citrate, etc., but there are very few reports on biosurfactants production using inexpensive raw materials as substrates (complex carbon or nitrogen sources) which can considerably reduce production costs in most biotechnological processes.To the best of our knowledge, no data are available on the use of animal by-products as a sole source of nutrient for biosurfactant production. In this study, biosurfactant production by a pure bacterial culture was studied using an agro-industrial waste: prickly pear fruits of (Opuntia ficus-indica) peels, and two animal by-products: sardine (Sardina pilchardus) heads and chicken (Gallus gallus domesticus) feet, since they are discarded as a waste.The fuel-contaminated soil samples used for isolation of microbial strains were collected in five different locations at a gas station located in Boumerdès, Algeria. The bacterial strains capable of producing biosurfactants was isolated by selective enrichment culture technique, which promotes the growth of microorganisms containing in the soil sample by providing them the essential nutrients. To demonstrate the ability of strains to produce biosurfactants, different tests were carried out : test of the emulsification index E24, test of the blood agar, test of the drop collapse and test of spreading of the hydrophobic phase. The results showed that prickly pear peels medium yielded the highest biosurfactant production, and gave the highest E24 and cleaning activity values, while chicken feet gave the highest foaming activity. However, extensive research is needed to establish the suitability of these two low-cost substrates in industrial-level biosurfactant production process.