Removal of zinc and cadmium ions from contaminated soils with rhamnolipid biosurfactant produced by Pseudomonas aeruginosa S7PS5

A soil treatment process using froth flotation technique involving anionic biosurfactant (rhamnolipids) using Sodium sulfide was studied. The supernatant produced by the strain Pseudomonas aeruginosa S7PS5 was tested for biosurfactants production, HPLC analysis showed the presence of L-rhamnosyl- β- hydroxydecanoyl- β-hydroxydecanoate (RL1) and L-rhamnosyl L-rhamnosyl- β-hydroxydecanoyl-β- hydroxydecanoate (RL2). The influence of the collector (rhamnolipid), pulp pH, a chemical activation step (sulfidization) and process time on metal removal efficiency has been investigated to recover Zn and Cd ions from a contaminated soil. An effective CMC of 35 mg/L was obtained. A perfect Zn and Cd removal efficiency was made at pH = 12 and 4 mg/g of Na2S during the first 5 min of soil washing process, then a longer flotation time ( > 5 min) caused mechanical entrainment of Zn and Cd.Keywords: Biosurfactants, flotation, Pseudomonas aeruginosa, rhamnolipids, soil washin

Organic Pollution Assessment and Biological Quality of the River Oued Rhiou (Algeria)

Organic pollution index OPI and biological river macrophyte index BRMI were evaluated in Oued Rhiou river. During the months of April, May and June 2014, results of biological oxygen demandBOD5, ammonium, nitrite and orthophosphate were used to calculate OPI. BMRI was calculated during June 2014, a vegetation development period of helophytes, hydrophytes and algae recoveries. During the three months of April, May and June, OPI evaluation reveals that sites S2 and S3, which receive anthropogenic releases are marked by a strong level of organic pollution. Site S1, which receives no effluent is characterized by a medium level of organic pollution. During June, the BRMI index indicates a strong trophic level in both S2 and S3 sites, cons, it shows a mean trophic level in S1 site

Contribution to risk management in industrial maintenance

International audienceSafety in maintenance seems particularly important due to the fact that maintenance situations are critical to the safety of operators. In addition to the nature of maintenance intervention, the criticality of maintenance tasks results also from the organizational environment in which they are carried out. This environment is composed of several elements that are human, technical and organizational, which are organized in order to achieve an intervention. This environment makes maintenance not only critical situations, but also complex situations. These are the views that will be developed in this paper, through the development of a methodological approach founded on systemic and consists of two phases. The first phase consists of risk analysis which is represented as a process of modeling a maintenance situation using two operational tools namely, UML (Unified Modeling Language) and the MADS (Analysis Method of Dysfunctional Systems) model. The second phase corresponds to risk management in maintenance by developing a synthetic approach in order to protect the health and safety of operators

Characterization of Fluorescent Rhizobacteria Isolated From Oleander (Nerium oleander L.) and Olivier (Olea oleaster L.) With Antagonistic Effect Against Fusarium oxysporum f. sp. radicis-lycopersici

This study aims to characterize the biocontrol potential of two fluorescent rhizobacteria isolated from Oleander (Nerium oleander L.) and Olivier (Olea oleaster L.). The isolation was done in Cetrimide agar. The fluorescing strains at 366 nm were selected for the dual plate assay against the tomato pathogen Fusarium oxysporum f.sp. radicis-lycopersici. The two best strains showing the highest inhibition rates (Pa2 and S2Pf1 with 31.36% and 51.42% respectively) were chosen to be identified and characterized for their production of antifungal molecules. The taxonomical determination based on macro and micromorphological observations in addition to the biochemical tests of the API 20E and API 20NE strips analyzed by the heuristic soft "PIBwin 2.0.0" suggests the strain Pa2 as a Pseudomonas aeruginosa while the strain S2Pf1 belongs to the Burkholderia cepacia species. The antifungal potential was assessed through the quantification/detection of the following bioactive molecules: salicylic acid, hydrogen cyanide, rhamnolipids, chitinases, and cellulases. The strain Burkholderia cepacia S2Pf1 showed a better antifungal profile in comparison to Pseudomonas aeruginosa Pa2. The determination of the growth kinetics parameters of Burkholderia cepacia S2Pf1 based on observed OD600 data, DModel data fitting, and Gompertz model data fitting highlighted a relatively good ability to quickly reach high bacterial densities in both nutrient and seed broths. Thus, Burkoledria cepacia S2Pf1 is suggested as a good candidate to be further assessed for its biocontrol proprieties against Fusarium oxysporum f.sp. radicis-lycopersici

Investigation of corrosion-resistant properties of aurantium oil in 1 M HCl

The fresh peel essential oils of citrus aurantium from Eastern Morocco (Oujda) have been analyzed by gas chromatography and gas chromatography–mass spectrometry. The analyzed essential oil consist mainly of monoterpene hydrocarbons (54.38%), with limonene (52.67%) being the major constituent. The effect of addition of citrus aurantium essential oil on the corrosion of steel in 1 M HCl acid has been studied by weight loss measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. The inhibition efficiency has been found to increase with inhibitor content to attain 95% (at 5 g/l). Data obtained from EIS studies have been analyzed to determinate the model inhibition process through appropriate equivalent circuit models. Inhibition efficiency obtained by the various methods is in good agreement. The adsorption of natural products on the steel surface has been found to obey the Langmuir’s adsorption isotherm.Проаналізовано склад оливи зі свіжих шкірок цитрусових за допомогою газової хроматографії та хроматомас-спектрометрії. Олива містить вуглеводні монотерпену (54,38%) та лімонену (52,67%). Гравіметричним та поляризаційним методами, а також імпедансної спектроскопії вивчено вплив її додатків на корозію сталі у розчині 1 М HCl. Ефективність інгібітора зі збільшенням вмісту до 5 g/l зростала на 95%. За результатами імпедансної спектроскопії побудовано еквівалентні моделі інгібування. Встановлено, що адсорбцію оливи на поверхні сталі описує ізотерма Ленгмюра.Проанализировано содержание масла из свежих шкурок цитрусовых с помощью газовой хроматографии и хроматомасс-спектрометрии. Масло содержит углеводороды монотерпена (54,38%) и лимонена (52,67%). Гравиметрическим и поляризационным методами, а также импедансной спектроскопии изучено влияние ее добавок на коррозию стали в растворе 1 М HCl. Эффективность ингибитора с ростом концентрации до 5 g/l увеличивалась на 95%. По результатам импедансной спектроскопии построены эквивалентные модели процесса ингибирования. Выявлено, что адсорбцию масла на поверхности стали описывает изотерма Ленгмюра

Phytochemical Profile, α-Glucosidase, and α-Amylase Inhibition Potential and Toxicity Evaluation of Extracts from Citrus aurantium (L) Peel, a Valuable By-Product from Northeastern Morocco

Due to the high volume of peel produced, Citrus by-product processing could be a significant source of phenolic compounds, in addition to essential oil. Citrus fruit residues, which are usually dumped as waste in the environment, could be used as a source of nutraceuticals. Citrus aurantium (L), also known as sour or bitter orange, is a member of the Rutaceae family and is the result of interspecific hybridization between Citrus reticulata and Citrus maxima. The purpose of this study is to chemically and biologically evaluate the peel of C. aurantium, which is considered a solid waste destined for abandonment. To achieve more complete extraction of the phytochemicals, we used a sequential extraction process with Soxhlet using the increasing polarity of solvents (i.e., cyclohexane, chloroform, ethyl acetate, acetone, and ethanol–water mixture). Essential oil (EO) from the Citrus peel, which was present at 1.12%, was also prepared by hydrodistillation for comparison. Various phytochemical assays were used to determine the qualitative chemical composition, which was subsequently characterized using GC-MS and HPLC-DAD. The inhibitory effects of C. aurantium peel extract on two enzymes, intestinal α-glucosidase and pancreatic α-amylase, were measured in vitro to determine their potential hypoglycemic and antidiabetic actions. Each extract had a significantly different phytochemical composition. According to GC-MS analyses, which allow the identification of 19 compounds, d-limonene is the most abundant compound in both EO and cyclohexane extract, at 35.17% and 36.15% (w/w). This comparison with hydrodistillation shows the value of the sequential process in extracting this valuable terpene in large quantities while also allowing for the subsequent extraction of other bioactive substances. On the contrary, linoleic acid is abundant (54.35% (w/w)) in ethyl acetate extract (EAE) with a lower amount of d-limonene. HPLC-DAD analysis allows the identification of 11 phytochemicals, with naringenin being the most abundant flavanone, detected in acetone extract (ACE) (23.94% (w/w)), ethanol–water extract mixture (EWE) (28.71% (w/w)), and chloroform extract (CFE) (30.20% (w/w)). Several extracts significantly inhibited α-amylase and/or α-glycosidase in vitro. At a dose of 332 g/mL, ACE, CFE, and EWE inhibited the two enzymes by approximately 98%. There were strong significant correlations between naringenin and α-glucosidase inhibition and between gallic acid and α-amylase inhibition. Molecular docking experiments further verified this. Finally, oral administration of C. aurantium extracts at a dose of 2000 mg/kg did not cause any effect on mice mortality or signs of acute toxicity, indicating that it is non-toxic at these doses. These findings suggest that C. aurantium peels could be a valuable by-product by providing a rich source of non-toxic phytoconstituents, particularly those with potential antidiabetic action that needs to be confirmed in vivo

Chemical composition, antioxidant and anticorrosive activities of Thymus Algeriensis.

International audienceKnown therapeutic applications of medicinal plants were made of them an alternative to synthetic compounds. In this situation, the present study was designed to give more knowledge and helping to exploit the leaves of Thymus algeriensis by determining the chemical composition of its essential oil, the phenolic content of the aqueous extract and evaluate the antioxidant and anticorrosive activity. The essential oil was characterized by Geranyl acetate (80.8%) as mainly compound. The aqueous extract has exhibited a moderate antioxidant activity against free radical DPPH. On the other hand, this work describes the successful performance of T. algeriensis as an eco-friendly corrosion inhibitor for acidic media. The corrosion inhibiting effect of the extract and the essential oil of T. algeriensis (TAE & TAO) on mild steel in 0.5 M H 2 SO 4 solution was investigated by electrochemical studies in the presence of different concentrations of TAE & TAO ranging from 0.25 g/L to 2 g/L. Potentiodynamic polarization showed that TAE and TAO behaves as mixed type inhibitors. Nyquist plots show that the efficiency of inhibition increases with increasing concentration of T. algeriensis and the increased charge transfer resistance