M. ARIECH Mounira

Biosurfactants are surfactant molecules produced by certain microorganisms (bacteria, yeasts, and fungi). Their nature as well as their surfactant power are strongly dependent on the type of microorganism, the species as well as the nutrient substrate available for cell development.
Among the different biosurfactants identified today, we find glycolipids, lipopeptides, phospholipids, neutral lipids, fatty acids or lipopolysaccharides. Just like their chemical synthesis counterparts, they can have emulsifying, foaming, wetting or even dispersing properties, but also more specific properties.
Currently, biosurfactants are of great interest in various areas of life thanks to their biodegradability and low toxicity, the objective of this study revolves around the production and characterization of biosurfactants from bacteria isolated from different soil samples, all isolates purified by successive subcultures of well-separated and macroscopically distinct colonies were checked for catalase, oxidase reaction and examined microscopically after gram staining. 24 isolates were screened for biosurfactant production on nutrient agar using the following tests: drop collapse test, oil dispersion test, emulsion stability test (ES%).
The drop collapse test is based on the destabilization of an oil droplet by surfactants in a 96-well microplate. The oil dispersion test is based on the dispersing activity of bacteria in a layer of the oil phase.
Whereas, the calculation of the emulsification index E24 makes it possible to verify the ability to form an emulsion between a hydrophobic phase and a hydrophilic phase. Only three strain was found to be efficient.
key words: biosurfactants, surface tension, screening, isolation, bacteria.

Biosurfactants are surfactant molecules produced by certain microorganisms (bacteria, yeasts, and fungi). Their nature as well as their surfactant power are strongly dependent on the type of microorganism, the species as well as the nutrient substrate available for cell development (Chen et al., 2007).
Among the different biosurfactants identified today, we find glycolipids, lipopeptides, phospholipids, neutral lipids, fatty acids or lipopolysaccharides.
Just like their chemical synthesis counterparts, they can have emulsifying, foaming, wetting or even dispersing properties, but also more specific properties (antibiotic properties).
Some of these functional properties can, moreover, be preserved under extreme conditions of use such as acidic pH, high temperature, and salinity (Meylheuc et al., 2001).
Given their potential and their safety, they are today used in different fields of application such as the environment, the oil industry, agronomy or even cosmetology and should quickly find their place in new sectors. applications such as the food, pharmaceutical and medical industries.
The objective of this study revolves around the production and characterization of biosurfactants from bacteria isolated from different samples

ABSTRACT: Galactomannans are the main component of locust bean gum from the fruit of the carob tree, Ceratonia siliqua L. They are a reserve of polysaccharides, found in the translucent endosperm of the seeds. They are designated as the best gels with thickening capacity and are, therefore, widely used as a natural food additive (E410) in many food, pharmaceutical and cosmetic preparations. In this study, we aim to exploit this gelling property of carob galactomannans in the microencapsulation of lactic bacteria in order to protect them from the negative effects of simulated digestive conditions. Two beneficial bacteria are used: Lactobacillus rhamnosus LBRE-LSAS and Bifidobacterium animalis subsp. lactis Bb12. Their survival in the free state or encapsulated in pure carob galactomannan gel combined with xanthan, was determined after residence in simulated in vitro digestive conditions (gastric: pH 2, pepsin 3 g/l and intestinal: bile 0.3%: W/V, pH 6.5. The results obtained show that gel encapsulation of carob galactomannans combined with xanthan improves the survival of these two beneficial strains to simulated digestive hostilities. the loss under gastric conditions 36.79% (3.55 log CFU/mL) for the non-encapsulated cells and only 12% (1.2 log CFU/mL) for the encapsulated ones. However, galactomannans alone do not appear to be effective in keeping a minimum of 106 bacterial cells viable when confronted with the hostile conditions of the digestive tract where they will be called upon to exert their positive effect on health. Keywords: Galactomannans; Xanthan; Encapsulation; Survival; Digestive Hostilities. 1. INTRODUCTION Probiotics are live microorganisms which, when administered in sufficient quantities, confer beneficial health effects on the host [1,2]. To exert health effects, it is recommended to ingest foods containing at least 106-107 colony forming units (CFU)/g of viable probiotics [3]. One of the major difficulties in the use of probiotics is their low viability during the crossing and stay in the different compartments of the digestive system where a large part of the cells is lost or inhibited by the bile secretions. Indeed, to be effective in their role, these micro-organisms must then colonize the intestine and multiply there. The low tolerance to acidity of certain bacterial species requires the implementation of means of protection and preservation of their integrity and survival in highly acidic environments such as the gastric

Abstract
Food neophobia describes the reluctance to taste an unfamiliar food, or a familiar food but
presented in a new form. It appears to be a normal phase of development, frequently encountered in
children. In Algeria, this type of study is rare, which justifies our commitment to study this subject. Our
survey was carried out on a sample of 746 schoolchildren, aged 6 to 10 years old, from the M'sila
region, including 360 girls and 386 boys to estimate the rate and level of food neophobia among these
children and to define the influence of their surroundings on this food behavior by answering two basic
questionnaires.
The results of the statistical analyses show that 12.06 % of the children in the population were
neophobic and no significant difference appeared in the level of food neophobia according to gender,
however, food neophobia evolves progressively with age. Multiple correspondence factor analysis
(MCFA) indicates that the media influences the choice of neophobic children.
Key words: Food neophobia, food, schoolchildren

L’invention se rapporte aux produits détergents eco-freindly, il s’agit d’un mélange d’acides gras
bactériens utilisable comme un biodégraissant désinfectant, développé pour le dégraissage et la
désinfection en profondeur des surfaces alimentaires. Il est efficace aussi contre les substances
organiques cambouis, les huiles minérales et les graisses. Il trouve son application comme un
dégraissant écologique, aux entreprises du secteur de l’énergie (stations d'essence et de vidange
d’huiles moteurs, dégraissages, et les milieux pollués par les hydrocarbures. etc.). Ainsi, pour
nettoyer et dégraisser toutes pièces mécaniques, moteurs, matériel de chantier ou de travaux publics

Background: Bioremediation processes are negatively affected by the low aqueous solubility
of some contaminants; therefore their bioavailability may be enhanced by the addition of
surfactants. These compounds are organic molecules that can be chemically and biologically
produced. Surfactants contain both hydrophilic and hydrophobic groups, therefore reducing
surface and interfacial tensions of immiscible fluids and increasing the solubility and sorption
of hydrophobic organic and inorganic compounds. The aim of our work is the
decontamination of a sandy soil artificially contaminated by hydrocarbons using the
biosurfactants produced by the strain Natrinema gari sp.
Materials/Methods : The effectiveness of cell‐free biosurfactant, derived from the culture
medium at the end of fermentation was investigated for the removal of oil from contaminated
sandy soils, with differents concentrations (1/2 CMC, CMC and 2 CMC) and at different time
of exposure (10 min, 120 min and 1440 min). The evaluation of biosurfactant action in the
removal of oil from different contaminated sandy soil was performed using a statistical
experimental.
Results: The strain Natrinema gari sp. is a potent producer of biosurfactant wich is able to
eliminate oil with a percentage of 88 % for a contact time of 10 min, 85% for 120 min and 89
% for 1440 min, but the cell culture was the best in remobilization than biosurfactant crude.
For a contact time of 10 min, the strain has an oil removal percentage of 98%, 96% for 120
min and 92% for 1440 min. The chemical surfactant (SDS) does not remove crude oil but it
changes their property. The biosurfactant produced by this strain, remain able of
decontaminating sands polluted by oil, using the bacterial cultures with a percentage of 100 %
or 2CMC of biosurfactant with a percentage of 98%.
Conclusion: The effectiveness of biosurfactants produced by Natrinema gari CH5, suggests
that it may be a preferable remediation method for the oil contamination soils.
Keywords :
Natrinema gari sp., biosurfactant, crude oil, decontamination, sandy soil.

Background: Bioremediation processes are negatively affected by the low aqueous solubility
of some contaminants; therefore their bioavailability may be enhanced by the addition of
surfactants. These compounds are organic molecules that can be chemically and biologically
produced. Surfactants contain both hydrophilic and hydrophobic groups, therefore reducing
surface and interfacial tensions of immiscible fluids and increasing the solubility and sorption
of hydrophobic organic and inorganic compounds. The aim of our work is the
decontamination of a sandy soil artificially contaminated by hydrocarbons using the
biosurfactants produced by the strain Natrinema gari sp.
Materials/Methods : The effectiveness of cell‐free biosurfactant, derived from the culture
medium at the end of fermentation was investigated for the removal of oil from contaminated
sandy soils, with differents concentrations (1/2 CMC, CMC and 2 CMC) and at different time
of exposure (10 min, 120 min and 1440 min). The evaluation of biosurfactant action in the
removal of oil from different contaminated sandy soil was performed using a statistical
experimental.
Results: The strain Natrinema gari sp. is a potent producer of biosurfactant wich is able to
eliminate oil with a percentage of 88 % for a contact time of 10 min, 85% for 120 min and 89
% for 1440 min, but the cell culture was the best in remobilization than biosurfactant crude.
For a contact time of 10 min, the strain has an oil removal percentage of 98%, 96% for 120
min and 92% for 1440 min. The chemical surfactant (SDS) does not remove crude oil but it
changes their property. The biosurfactant produced by this strain, remain able of
decontaminating sands polluted by oil, using the bacterial cultures with a percentage of 100 %
or 2CMC of biosurfactant with a percentage of 98%.
Conclusion: The effectiveness of biosurfactants produced by Natrinema gari CH5, suggests
that it may be a preferable remediation method for the oil contamination soils.
Keywords :
Natrinema gari sp., biosurfactant, crude oil, decontamination, sandy soil.

Dans le cadre de la valorisation des produits issus de la recherche scientifique, la Direction Générale de la Recherche Scientifique et du Développement Technologique (DGRSDT) aorganisé la deuxième édition du Salon National des Produits de la Recherche les 2, 3 et 4 juillet 2018 au Palais des Expositions, Pins Maritimes – Alger.

Résumé
Les Haloarchaea sont des Archaea halophiles, inclus dans un ordre et une famille uniques, nommés Halobacteriales et Halobacteriaceae, respectivement. Elles survivent dans les milieux à très fortes concentrations en sel (NaCl>1,5M). Actuellement, les Haloarchaea présentent un grand intérêt grâce à leur capacité de produire les molécules bioactives telles que les biosurfactants qui ont des applications très importantes dans divers domaines de la vie ; vue les propriétés fonctionnelles de ces molécules, dont les propriétés d’emulsification et la réduction de la tension superficielle. Dans le présent travail, nous avons effectué un screening de la capacité de produire les biosurfactants par six isolats des bactéries halophiles extrêmes, isolées des sols salins de Chott El Hodna-M’sila, en utilisant quatre tests. Tous les résultats montrent que les isolats CH2 et CH5, sont actifs et capables de produire à la fin de la phase stationnaire de croissance, des biosurfactants extracellulaires, qui demeurent stables aux variations de la température,du pH et de la salinité . Les concentrations micellaires critiques déterminées sont : CMCCH2=280 mg/l et CMCCH5=80 mg/l. L’optimisation des conditions physico-chimiques et nutritionnelles qui influencent la production des biosurfactants a donné les meilleurs résultats à savoir un % RTS=68.54±0.7% pour l’isolat CH2 ; une valeur qui correspond à une TSCH2=20.66±0.1 mN.m-1. De même pour l’isolat CH5, les meilleurs résultats obtenus sont les suivants : %RTSCH5=48.52±0.5% ; une valeur qui correspond à une TSCH5=35.67±0.2 mN.m-1. L’identification de ces molécules par GC-MS a permis de conclure que les biosurfactants produits par l’isolat CH2 et CH5 sont constitués essentiellement d’acides gras. Ces biosurfactants demeurent capables de décontaminer les sables pollués par le pétrole, en utilisant le moût de fermentation ou les biosurfactants à 2 CMC avec un pourcentage d’élimination de 100% avec un pourcentage d’ellimination de 98%

Mots Clés : Archaea halophiles biosurfactants screening tension superficielle

A halophilic, Gram-negative bacterial strain, designated CH7, which was isolated from saline soils of Chott El Hodna, M’sila-Algeria, was subjected to a polyphasic taxonomic study. Overall, the phenotypic, genotypic and phylogenetic results demonstrate that strain CH7 represents a member of the genus Halomonas. The 16S rRNA gene sequence of this strain shows highest similarity of 99.8 % with Halomonas caseinilytica DSM 23509T . This potent biosurfactant producer and diesel degrader, was obtained after screening involving ; drop collapsing method (DCM), oil-spreading method (OSM), surface tension mesurement (STM) and emulsification index (E24). This strain was found to be a potent producer of biosurfactant in SG broth containing diesel oil as the carbon source and found to be able to degrad diesel oil. The quantitative biodegradation efficiency (BE%) of diesel was 45.88%, over a period of 15 days, calculated by gas chromatography mass spectrum analysis (GC-MS). The biosurfactant showed high physicochemical properties in terms of the surface activities, and reducing the surface tension to 23.00 ± 0.5 mN.m-1 and its critical micelle concentration (CMC) was found to be 46 mg.L-1, with emulsification index of 82 ± 0.5 %. The biosurfactant showed thermal and pH stability regarding stability emulsion, also under salinity ranges.
Key words
Biosurfactants, biodegradation, diesel, emulsion, Halomonas, halophilic bacteria, surface tension.

Abstract
Biosurfactant (BS) are a type of surface-active molecules that reduce the interfacial tension between two liquids,
or that between a liquid and a solid. Their unique property like, nontoxic, easily biodegradable, eco-friendly and
high stability, and wide variety of industrial application makes them highly useful group of chemical compound.
BS are produced from variety of microorganisms. The objective of this study was to isolate and characterize the
BS producingby Natrinema gari sp., halophilic archeon isolated from salin soils of Chott El Hodna, M'sila-
Algeriaand identified by 163 rRNA sequencing. BS production ability was evaluated by carrying out drop
collapse and oil spreading tests, measurement of surface tension and estimation of emulsification activity.
Properties of this BS were determined like charactrization of BS by TLC and GC-MS methods. It was analysed
and identified as lipid-biosurfactant and GC-MS analysis revealed that they are predominantly made up of a
benzene with a percent age of 50Yo, and a mixture of fatly acids (palmitic acid, stearic acid and linoleic acid).
Keywords
Natrinema gari sp., biosurfactants, Haloarchaea, GC-MS, faffy acids, screening.

L’expérimentation animale consiste à utiliser des animaux comme substitut ou « modèle », pour mieux comprendre la physiologie d'un organisme et ses réponses à divers facteurs (alimentation, environnement, agents pathogènes) ou substances (pour en tester, vérifier ou évaluer l'efficacité, l'innocuité ou la toxicité), et tout particulièrement pour tenter de prévoir ce qui se passe chez l'Homme.

Abstract
Biosurfactant (BS) are a type of surface-active molecules that reduce the interfacial tension between two liquids,
or that between a liquid and a solid. Their unique property like, nontoxic, easily biodegradable, eco-friendly and
high stability, and wide variety of industrial application makes them highly useful group of chemical compound.
BS are produced from variety of microorganisms. The objective of this study was to isolate and characterize the
BS producingby Natrinema gari sp., halophilic archeon isolated from salin soils of Chott El Hodna, M'sila-
Algeriaand identified by 163 rRNA sequencing. BS production ability was evaluated by carrying out drop
collapse and oil spreading tests, measurement of surface tension and estimation of emulsification activity.
Properties of this BS were determined like charactrization of BS by TLC and GC-MS methods. It was analysed
and identified as lipid-biosurfactant and GC-MS analysis revealed that they are predominantly made up of a
benzene with a percent age of 50Yo, and a mixture of fatly acids (palmitic acid, stearic acid and linoleic acid).
Keywords
Natrinema gari sp., biosurfactants, Haloarchaea, GC-MS, faffy acids, screening.

Biosurfactants are surface active agents with broad range commercial applications in various industries and have considerable advantages over their chemical counterparts. In this study, drop collapse assay, oil spreading assay, emulsification assay and surface tension measurement were compared for their reliability and ease of use to screen biosurfactant producing six extremely halophilic bacteria isolated from saline soil of Chott El Hodna-M’sila (Algeria), which is considered as a thalassohaline environment. Results from screening methods revealed that, CH2 and CH5 strains are potential candidates for biosurfactant production. Among these, there was a very strong negative linear correlation between the emulsification index and surface tension (rs= - 0.987) and a strong negative linear correlation between the oil spreading technique and surface tension (rs= - 0.971) and a weaker negative correlation between the drop collapse method and surface tension (rs= - 0.807), suggesting that strains highly active in any one of these methods were active in other three methods. As every method has its advantages and disadvantages, a combination of different methods is appropriate for a successful screening.
Key words
Biosurfactant, halophilic bacteria, drop collapse assay, oil spreading assay, emulsification assay, surface tension.

Biosurfactants are surface active agents with broad range commercial applications in various industries and have considerable advantages over their chemical counterparts. In this study, drop collapse assay, oil spreading assay, emulsification assay and surface tension measurement were compared for their reliability and ease of use to screen biosurfactant producing six extremely halophilic bacteria isolated from saline soil of Chott El Hodna-M’sila (Algeria), which is considered as a thalassohaline environment. Results from screening methods revealed that, CH2 and CH5 strains are potential candidates for biosurfactant production. Among these, there was a very strong negative linear correlation between the emulsification index and surface tension (rs= - 0.987) and a strong negative linear correlation between the oil spreading technique and surface tension (rs= - 0.971) and a weaker negative correlation between the drop collapse method and surface tension (rs= - 0.807), suggesting that strains highly active in any one of these methods were active in other three methods. As every method has its advantages and disadvantages, a combination of different methods is appropriate for a successful screening.



Key words: Biosurfactant, drop collapse, emulsification stability, extremely halophilic bacteria, oil spreading, surface tension.

Drop collapse assay, oil spreading assay, emulsification assay and surface tension measurement were compared for their reliability and ease of use to screen biosurfactant producing six extremly halophilic archaea isolated from saline soil of Chott El Hodna-M’sila (Algeria), which is considered as a thalassohaline environment. Results from screening methods revealed that, CH2 and CH5 strains are potential candidates for biosurfactant production. Among these, there was a very strong negative linear correlation between the emulsification index and surface tension (rs= - 0.987) and a strong negative linear correlation between the oil spreading technique and surface tension (rs= - 0.971) and a weaker negative correlation between drop collapse method and surface tension (rs= - 0.807), suggesting that strains highly active in any one of these method were active in other three methods. As every method has its advantages and disadvantages, a combination of different methods is appropriate for a successful screening.

Keywords
Biosurfactant. Drop collapse. Emulsification stability. Halophilic Archaea. Oil spreading. Surface tension.

Abstract :
Biosurfactants are the surface-active molecules synthesized by microorganisms. The present study was focused on screening of biosurfactant producing halophilic bacteria. Total three methods were employed to test the biosurfactant production in six halophilic strains by drop collapsing method and oil spreading method. The results of the latest method were ranged from 78.73 ± 02.85 - 246.22 ± 08.79 mm2. And finally, the emulsifying capacity of these strains was evaluated by the E24 emulsification index and it ranged from 08.68 -80.00 %. With the advantage of environmental compatibility. In conclusion, interest in biosurfactants has led to the developement of a multitude of methods for the screening of biosurfactant producing strains. As every method has its advantages and disadvantages, a combination of different methods is appropriate for a successful screening.

Keywords:
Biosurfactant; Drop collapsing test; Emulsification index ; Oil displacement test.

Biological control such as the use of plant extracts has emerged as promising option to the phenomena of microorganisms resistance to chemical. Several constituent of essential oil have been studied for their biological activity including antibacterial and antifungal activity. In this study the effect of Saccocalyx satureioides essential oil with different concentrations was test against the growth of some bacteria and moulds.
Saccocalyx satureioides was treated by hydrodistillation in order to obtain its essential oils. The method gave an output of 1.8%.
The test of the inhibiting capacity of these EO, diluted to 50% and 33.33%, on the growth of some bacteria and moulds presented a strong antimicrobial activity reaching more than 50%.The essential oil of Saccocalyx satureioides a broad spectrum of activity as it inhibits both the growth of bacteria that moulds and yeasts.
Its antimicrobial activity is mainly a function of its chemical composition. It acts by preventing the growth of bacteria and yeast, whereas it inhibits spore germination, elongation of mycelium, sporulation and production of exudates from the moulds.
Key words
Antimicrobial activity, Essential oils, Hydrodistillation, Saccocalyx satureioides.

Biological control such as the use of plant extracts has emerged as promising option to the phenomena of microorganisms resistance to chemical. Several constituent of essential oil have been studied for their biological activity including antibacterial and antifungal activity. In this study the effect of Saccocalyx satureioides essential oil with different concentrations was test against the growth of some bacteria and moulds.
Saccocalyx satureioides was treated by hydrodistillation in order to obtain its essential oils. The method gave an output of 1.8%.
The test of the inhibiting capacity of these EO, diluted to 50% and 33.33%, on the growth of some bacteria and moulds presented a strong antimicrobial activity reaching more than 50%.The essential oil of Saccocalyx satureioides a broad spectrum of activity as it inhibits both the growth of bacteria that moulds and yeasts.
Its antimicrobial activity is mainly a function of its chemical composition. It acts by preventing the growth of bacteria and yeast, whereas it inhibits spore germination, elongation of mycelium, sporulation and production of exudates from the moulds.
Key words
Antimicrobial activity, Essential oils, Hydrodistillation, Saccocalyx satureioide

Abstract :
The current study describes the extracellular hydrolytic activities of halophilic archaea isolated from salin soils of Chott El Hodna (M’sila). The estimated number of grown colonies was approximately 38 per gram of saline soil on the surface of the medium containing 25% NaCl.
The investigated strains, randomly selected from the colonies observed on the plate, showed at least one of the tested extracellular hydrolytic activities and one strain hydrolized six out of seven tested substrates. Our investigations showed that hydrolytic activities for Tween 80, casein and gelatin are predominant among the isolated strains although the NaCl concentration varies up to 25%.
The presence of combined hydrolytic activities in some isolated strains could be an advantage to use in some biotechnological applications in various fields of industry or agriculture. To the author’s knowledge, this is the first study on the extracellular hydrolytic properties of halophilic archaea isolated from Chott El Hodna, which was classified as an important international wetland by the RAMSAR Convention.
Key words:
Extremozymes, halophilic archaea,hydrolytic activities, halophilic enzymes, salt.

Abstract :
The current study describes the extracellular hydrolytic activities of halophilic archaea isolated from salin soils of Chott El Hodna (M’sila). The estimated number of grown colonies was approximately 38 per gram of saline soil on the surface of the medium containing 25% NaCl.
The investigated strains, randomly selected from the colonies observed on the plate, showed at least one of the tested extracellular hydrolytic activities and one strain hydrolized six out of seven tested substrates. Our investigations showed that hydrolytic activities for Tween 80, casein and gelatin are predominant among the isolated strains although the NaCl concentration varies up to 25%.
The presence of combined hydrolytic activities in some isolated strains could be an advantage to use in some biotechnological applications in various fields of industry or agriculture. To the author’s knowledge, this is the first study on the extracellular hydrolytic properties of halophilic archaea isolated from Chott El Hodna, which was classified as an important international wetland by the RAMSAR Convention.
Key words:
Extremozymes, halophilic archaea,hydrolytic activities, halophilic enzymes, salt.

La diversité et la densité des bactéries halophiles dans les sols salins et les eaux salées de Chott El Hodna (M'sila), ont été étudiés, en incluant trois sites de prélèvement pour les eaux et quatre sites de prélèvement pour le sol, dans des systèmes écologiques différents. Les propriétés physico - chimiques du sol et des eaux ont été analysées. Les échantillons collectés à partir des saumures salines de Chott El Hodna, ont été trouvés thalassohalines, en raison de la dominance des ions de sodium et des chlorures avec un pH de 8,0.
Les densités des bactéries halophiles faibles, modérées et extrêmes, ont été mesurées en utilisant un milieu de culture salé contenant 3%, 8%, et 25% respectivement. La densité des bactéries halophiles faible était la plus élevée, suivie par les bactéries halophiles modérées puis les bactéries hyper halophiles. Vingt isolats d’archéobactéries hyper halophiles et une bactérie halotolérante ont été sélectionnés pour la caractérisation, en adoptant la comparaison de leurs caractéristiques phénotypiques avec d’autres espèces déjà identifiés dans le Manuel de Bergey pour la systématique en bactériologie. Ces isolats peuvent être identifiés comme appartenant à sept genres et dix espèces. Les genres sont: Halopherax, Haladaptatus, Halococcus, Natrinema, Haloplanus, Natrialba. Halomonas.
La production du beta-carotène par les espèces chromogènes (Halopherax volcanii. Halococcus morrhuae. Halococcus qingdaonensis. Natrinema pallidum. Natrinema pellirubrum. Haloferax mediterrane.), a été révélée par la méthode de chromatographie sur couche mince (CCM).
La caractérisation de ces isolats, en utilisant une combinaison des caractéristiques phénotypiques, une analyse des acides gras de la paroi, et l’analyse des séquences d’ARNr16S, est recommandée pour une utilisation future de ces isolats pour des applications en biotechnologie.
Mots clés :
Chott El Hodna, Archéobactéries hyper halophiles, Caroténoïdes, Eaux salées, Sols salins, Thalassohaline.

La diversité et la densité des bactéries halophiles dans les sols salins et les eaux salées de Chott El Hodna (M'sila), ont été étudiés, en incluant trois sites de prélèvement pour les eaux et quatre sites de prélèvement pour le sol, dans des systèmes écologiques différents. Les propriétés physico - chimiques du sol et des eaux ont été analysées. Les échantillons collectés à partir des saumures salines de Chott El Hodna, ont été trouvés thalassohalines, en raison de la dominance des ions de sodium et des chlorures avec un pH de 8,0.
Les densités des bactéries halophiles faibles, modérées et extrêmes, ont été mesurées en utilisant un milieu de culture salé contenant 3%, 8%, et 25% respectivement. La densité des bactéries halophiles faible était la plus élevée, suivie par les bactéries halophiles modérées puis les bactéries hyper halophiles. Vingt isolats d’archéobactéries hyper halophiles et une bactérie halotolérante ont été sélectionnés pour la caractérisation, en adoptant la comparaison de leurs caractéristiques phénotypiques avec d’autres espèces déjà identifiés dans le Manuel de Bergey pour la systématique en bactériologie. Ces isolats peuvent être identifiés comme appartenant à sept genres et dix espèces. Les genres sont: Halopherax, Haladaptatus, Halococcus, Natrinema, Haloplanus, Natrialba. Halomonas.
La production du beta-carotène par les espèces chromogènes (Halopherax volcanii. Halococcus morrhuae. Halococcus qingdaonensis. Natrinema pallidum. Natrinema pellirubrum. Haloferax mediterrane.), a été révélée par la méthode de chromatographie sur couche mince (CCM).
La caractérisation de ces isolats, en utilisant une combinaison des caractéristiques phénotypiques, une analyse des acides gras de la paroi, et l’analyse des séquences d’ARNr16S, est recommandée pour une utilisation future de ces isolats pour des applications en biotechnologie.
Mots clés :
Chott El Hodna, Archéobactéries hyper halophiles, Caroténoïdes, Eaux salées, Sols salins, Thalassohaline.