Ahmed Lebrihi

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Verified

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• Eng; PhD; HDR
• Professor (Full) at National Polytechnic Institute of Toulouse

Thymus capitatus Hoff. et Link. essential oil was constituted by thymol (89.06%) as a major component followed by p-cimene (5.04%) and g-terpinene (3.19%) after analysis by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. The antioxidant activity assays of the essential oil used in the inhibition of the radica...

Some soil-borne microorganisms are known to have the ability to solubilize insoluble rock phosphate and this process often involves the excretion of organic acids. In this issue, we describe the characterization of a novel solubilizing mechanism used by a Streptomyces strain related to Streptomyces griseus isolated from Moroccan phosphate mines. Th...

Essential oil (EO) of Laurus nobilis, from Tunisian, France and Austrian were screened for their chemical composition, antioxidant and antimicrobial activities and compared. GC-MS analysis showed that leaves of Tunisian L. nobilis had camphor (34.43%), 1,8-cineole (20.21%) and α-terpineol (7%) as major components. France and Austrian EOs had a high...

The petroleum sludge composting in a bioreactor with green wastes was made in interest to assess the organic matter biotransformation, the total petroleum hydrocarbons biodegradation and the maturity of the final product. During the composting process the C/N and NH4⁺/NO3⁻ ratios decreased to reach values of maturity for the second test B. Otherwis...

Fungi have always attracted a lot of attention as they are able to produce a vast repertoire of enzymes that find a broad spectrum of uses in biotechnological and industrial fields. Undoubtedly, one of the most promising biocatalysts is the lipase, which has been widely used for the biotransformation of a number of commercial products due to its hi...

The purpose of this study is to assess the maturity and stability of the lagooning sludge (LS) with green waste (GW) during semi-industrial composting. Physico-chemical parameters, spectroscopy analysis and germination test were monitored. After 105 days, the decomposition rate of about 33.6; 39 and 36%, a stabilization of pH around neutrality; NH4...

Saccharothrix algeriensis NRRL B‐24137 is an actinobacterium isolated from Algerian Saharan soil. It produces bioactive compounds belonging to the dithiolopyrrolone class of antibiotics, which are characterized by the possession of a unique pyrrolinonodithiole nucleus. Dithiolopyrrolones are known for their strong antibacterial and antifungal activ...

The present work aims to evaluate the capacity of a yeast strain to degrade the olive mill wastewater (OMWW) and to obtain a stabilized product that can be disposed without any environmental impact on the water-soil-plant system. The pollutant load, expressed by the chemical oxygen demand (COD) and the phenolic compounds (PC), are 187.63 and 4.30 g...

This study investigates the landfill leachate generated from three landfills with different ages and operations in a semi-arid climate and assesses major differences in qualitative and quantitative leachate characteristics compared with other landfills located in different areas with similar climatic conditions and economic situation. These sites a...

In this investigation, petroleum sludge landfilling was carried out in order to assess the biodegradation degree and the final product quality. The microbial analysis showed a good microorganism proliferation which reinforces the biodegradation process. The total mesophilic and thermophilic microflora evaluated symmetrically as they increased at th...

Dithiolopyrrolone antibiotics, produced by several microorganisms, are known for their strong antimicrobial and antitumor activities. Among of this microorganisms, Saccharothrix algeriensis NRRL B‐24137, a rare actinobacterium, has the abillity to produce several dithiolopyrrolones derivatives depending on precursors added in the culture medium. Af...

Simultaneous in vivo measurements of prompt fluorescence (PF), delayed fluorescence (DF) and modulated reflection (MR) at 820-nm were used to assess effect of short desiccation period (4.5 h) on Parmelina tiliacea lichen. The two performance indexes (PIABS and PItotal) as a measure of an overall photosynthetic thalli performance showed a negative e...

This work aimed to investigate the effect of benzoic acid and humic acid on the growth of Saccharothrix algeriensis DSM 44581 on semi-synthetic medium by using controlled batch fermentors. The maximum biomass values were 6.54, 8.54 and 7.32 g/l for the control and in the presence of benzoic acid and humic acid, respectively. After 48 hours of ferme...

Saccharothrix algeriensis DSM 44581T, is an actinobacterim producer of several antibiotics: thiolutin, tiglyl-pyrrothine, sénécioyl-pyrrothine, butyryl and isobutyryl-pyrrothine pyrrothine, belong to pyrrothine group known for its interesting biological activities. The pyrrothines have a particular structure formed of heterocycles on which is attac...

During screening for potentially antimicrobial actinobacteria, a highly antagonistic strain, designated WAB9, was isolated from a Saharan soil of Algeria. A polyphasic approach characterized the strain taxonomically as a member of the genus Streptomyces. The strain WAB9 exhibited a broad spectrum of antimicrobial activity towards various multidrug-...

The effects of culture media (YES, CYA, SNM), temperature (10, 15, 20, 25, 30 and 37°C), incubation time (5, 10, 15 and 20 days) and their interactions on radial growth and OTA production by six A. tubingensis and two A. niger were studied. Growth rate increased as temperature increased, regardless of the culture media and isolates. Total inhibitio...

AimsTo provide, an efficient technique of monitoring the off-flavored fungal compound geosmin.Methods and ResultsGeosmin associated gpe1 gene of Penicillium expansum displayed >99% similarity to cytochrome P450 gene of geosmin producing P. restrictum, but <40% similarities to geosmin biosynthesis, non-cytochromic gene of Streptomyces avermitilis an...

Tunisian Sour oranges leaves were studied. Alimentary preparations of C. aurantium were obtained by maceration, infusion, decoctions (15, 30 and 60 minutes). Different yields were obtained for different extractions. Their chemical composition was evaluated revealing few amounts of tannins and anthocyanins whereas some of them presented considerable...

Actinomycetes are bacteria producing secondary metabolites, they are known for their roles in agriculture: improving the soil structure and the production of plant growth factors. 24 strains of actinomycetes were isolated from four samples of the ground Meknes; these isolates were tested in vitro by the production of growth-promoting substances, fo...

Background and aim Saccharothrix algeriensis NRRL B-24137, isolated from a Saharan soil, has been described as a potential biocontrol agent against Botrytis cinerea and other phytopathogens. However, the plant protection mechanisms involved still need to be described. The aim of this study was to determine this protection phenomenon as well as par...

The dithiolopyrrolone class of antibiotics has been known to display bacteriostatic activity against both Gram-positive and Gram-negative bacteria and exert other biological activities. Acyltransferase activities are proposed to be responsible for the structural diversity of dithiolopyrrolones produced by Saccharothrix algeriensis NRRL B-24137. Mor...

Saccharothrix algeriensis NRRL B-24137 produced naturally different dithiolopyrrolone derivatives. An enzymatic activity pyrrothine N-acyltransferase was targeted to be responsible for the transfer of acyl group from acyl-CoA to pyrrothine core. This activity was also reported to be responsible for the diversity of dithiolopyrrolone derivatives. Ba...

A halophilic actinomycete strain, designated H55(T), was isolated from Saharan soil sampled in the Mzab region (Ghardaia, southern Algeria) and was characterized in a taxonomic study using a polyphasic approach. The cell wall was determined to contain meso-diaminopimelic acid and the characteristic whole-cell sugars were arabinose and galactose. Th...

Grapevine is one of the most important economic crops yielding berries, wine products as well as derivates. However, due to the large array of pathogens inducing diseases on this plant, considerable amounts of pesticides—with possible negative impact on the environment and health—have been used and are currently used in viticulture. To avoid negati...

Background and aim There is currently a gap of knowledge regarding whether some beneficial bacteria isolated from desert soils can colonize epi- and endophytically plants of temperate regions. In this study, the early steps of the colonization process of one of these bacteria, Saccharothrix algeriensis NRRL B-24137, was studied on grapevine roots t...

A novel halophilic actinomycete strain, H23(T), was isolated from a Saharan soil sample collected in Djamâa (Oued Righ region), El-Oued province, South Algeria. Strain H23(T) was identified as a member of the genus Actinopolyspora by a polyphasic approach. Phylogenetic analysis showed that strain H23(T) had 16S rRNA gene sequence similarities rangi...

The taxonomic position of a novel actinomycete, strain SA152T, isolated from a sample of Algerian Saharan soil, was determined using a polyphasic taxonomic approach. The strain produced abundant aerial mycelium and fragmented substrate mycelium on most media tested. Chemotaxonomically and phylogenetically, the strain was related to the members of t...

##Assembly-Data-START## Assembly Method :: MEGA v. 5 Sequencing Technology :: Applied Biosytems 3730XL ##Assembly-Data-END##

##Assembly-Data-START## Assembly Method :: MEGA v. 5 Sequencing Technology :: Applied Biosytems 3730XL ##Assembly-Data-END##

Actinomycete strain SA198, isolated from a Saharan soil sample of Algeria, exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria, and phytopathogenic and toxinogenic fungi. The morphological and chemotaxonomic characteristics of the strain were consistent with those of the genus Saccharothrix. Analysis of the 16S rRNA ge...

A novel halophilic actinomycete, strain H32T, was isolated from a Saharan soil sample collected in El-Oued province, south Algeria. The isolate was characterized by means of polyphasic taxonomy. Optimal growth was determined to occur at 28–32 °C, pH 6.0–7.0 and in the presence of 15–25 % (w/v) NaCl. The strain was observed to produce abundant aeria...

Neroli essential oil is extracted from the fragrant blossoms of the bitter orange tree. It is one of the most widely used floral oils in perfumery. In this study chemical composition and in vitro antimicrobial and antioxidant activities of neroli oil are investigated. The essential oil of fresh Citrus aurantium L. Flowers (Neroli oil) cultivated in...

During a screening for potential plant disease control actinomycetes, a total of 133 strains were isolated from Saharan soil samples of seven Algerian regions by dilution technique on chitin-vitamins agar medium. Screening for antagonistic properties using streak assay method showed that 25% of isolates demonstrated strong activities against a wide...

  Citrus aurantium leaves' essential oils (EOs) were evaluated for chemical composition and antioxidant and antibacterial activities. The vegetable material, taken 5 times during the year, has undergone the hydrodistillation to prepare EO. Chemical characterization by gas chromatography/mass spectrometry and GC/flame ionization detection allowed th...

In this study, essential oil and various extracts (hexane, petroleum ether, acetone, ethanol, methanol and water) of Eucalyptus gilii were screened for their chemical composition, antimicrobial and antioxidant activities. The essential oil chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame...

A halophilic actinomycete strain designated H19(T), was isolated from a Saharan soil in the Bamendil region (Ouargla province, South Algeria) and was characterized taxonomically by using a polyphasic approach. The morphological and chemotaxonomic characteristics of the strain were consistent with those of members of the genus Actinopolyspora, and 1...

Geosmin is a terpenoid, an earthy-smelling substance associated with off-flavors in water and wine. The biosynthesis of geosmin is well characterized in bacteria, but little is known about its production in eukaryotes, especially in filamentous fungi. The origin of geosmin in grapevine is largely attributable to the presence of Penicillium expansum...

Ochratoxine A (OTA), a potential human carcinogen is produced by several species of Aspergillus and Penicillium, including Aspergillus westerdijkiae. In this study a putative polyketide synthase gene aolc35-12 has been partially cloned from A. westerdijkiae. The predicted amino acid sequence of the 3.22 kb clone was found to have a high degree of s...

An actinomycete strain designated SA181T, was isolated from Saharan soil in the Hoggar region (South Algeria) and was characterized taxonomically by using a polyphasic approach. The morphological and chemotaxonomic characteristics of the strain were consistent with the members of the genus Saccharothrix, and 16S rRNA gene sequence analysis confirme...

An actinomycete strain designated PAL54, producing an antibacterial substance, was isolated from a Saharan soil in Ghardaïa, Algeria. Morphological and chemical studies indicated that this strain belonged to the genus Saccharothrix. Analysis of the 16S rDNA sequence showed a similarity level ranging between 96.9 and 99.2% within Saccharothrix speci...

Study of the taxonomy and the biological activity of the actinomycete strain PAL111 against several pathogenic and toxigenic microorganisms for humans, and resistant to many antibiotics. The taxonomic study of isolate PAL111 is carried out on the basis of phenotypic and molecular characteristics. The tests against the pathogenic microorganisms are...

Objective Study of the taxonomy and the biological activity of the actinomycete strain PAL111 against several pathogenic and toxigenic microorganisms for humans, and resistant to many antibiotics. Materials and methods The taxonomic study of isolate PAL111 is carried out on the basis of phenotypic and molecular characteristics. The tests against t...

A new halophilic actinomycete strain, designated H16, has been isolated from a hypersaline Saharan soil in Ouargla province (southern Algeria) and characterized taxonomically using a polyphasic approach. The strain grew at 18–50°C, pH 5–9, and 7–32% (w/v) NaCl. It produced abundant aerial mycelia, which formed long chains of rod-shaped spores at ma...

Two Bacillus sp. strains (B29 and B27) isolated from soil in the South of Tunisia were tested for their abilities to produce antimicrobial compounds. Both strains showed antimicrobial activity against Gram-positive and Gram-negative bacteria, yeasts and fungi. The produced compounds were extracted by using four different solvents. The hexane solven...

The diversity of a population of 52 halophilic actinomycetes was evaluated by a polyphasic approach, which showed the presence of members of the Actinopolyspora, Nocardiopsis, Saccharomonospora, Streptomonospora, and Saccharopolyspora genera. One strain was considered to be a new member of the last genus, and several other strains seemed to be new...

A moderately halophilic actinomycete strain designated AH97 was isolated from a saline Saharan soil, and selected for its antimicrobial activities against bacteria and fungi. The AH97 strain was identified by morphological, chemotaxonomic and phylogenetic analyses to the genus Actinoalloteichus. Analysis of the 16S rDNA sequence of strain AH97 show...

Mycotoxins are secondary metabolites present worldwide in agricultural commodities and produced by filamentous fungi that cause a toxic response (mycotoxicosis) when ingested by animals. Prevention of mycotoxicoses includes pre- and post-harvest strategies. The best way to reduce the mycotoxin content in food and feed is the prevention of mycotoxin...

Aflatoxins (AFs) represent the most important single mycotoxin-related food safety problem in developed and developing countries as they have adverse effects on human and animal health. They are produced mainly by Aspergillus flavus and A. parasiticus. Both species have different aflatoxinogenic profile. In order to distinguish between A. flavus an...

Essential oils obtained by hydrodistillation from the different parts (stems, adult leaves, immature flowers and fruits) of Eucalyptus oleosa were screened for their antioxidant and antimicrobial properties and their chemical composition. According to GC-FID and GC-MS, the principal compound of the stem, immature flowers and the fruit oils was 1,8-...

The development of a culture medium in which the growth rate was limited by initial phosphate concentration permitted spiramycin production during the growth phase. The influence of the growth rate on spiramycin production in this medium was studied. Addition of glycerol before spiramycin production increased the growth rate by 100% and spiramycin...

Dithiolopyrrolone antibiotics, produced by several microorganisms, are known for their strong antimicrobial activities. This class of antibiotics generated new interest after the discovery of their anticancer and antitumor properties. In this study, four new antibiotics were purified from the fermentation broth of Saccharothrix algeriensis NRRL B-2...

Thirty litres of fermentation broth was extracted from the newly isolated Streptomyces sp. strain TN17 and various separation and purification steps led to the isolation of three pure bioactive compounds (1-3). Compound 1: cyclo (L-Leu-L-Arg), a diketopiperazine 'DKP' derivative; 2: di-(2-ethylhexyl) phthalate, a phthalate derivative; and 3: cyclo...

Cited By (since 1996):21, Export Date: 18 October 2014

Ce projet vise à élaborer une stratégie de lutte contre la production des molécules néfastes à l’origine des ‘goûts moisi-terreux’ (GMT), et de l’’arôme de champignon frais (ACF)’ sur les vins de plusieurs régions viticoles françaises, en caractérisant l’ensemble des espèces fongiques responsables de cette production et en établissant des descripte...

Thymus capitatus Hoff. et Link. essential oil was constituted by thymol (89.06%) as a major component followed by p-cimene (5.04%) and γ-terpinene (3.19%) after analysis by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. The antioxidant activity assays of the essential oil used in the inhibition of the radica...

A stoichiometric reaction scheme for Saccharothrix algeriensis growth and thiolutin production. (2010) Process Biochemistry, vol. 45 (n° 11). pp. 1808-1815. ISSN 1359-5113 Open Archive Toulouse Archive Ouverte (OATAO) OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where p...

Wheat and its derivatives are a very important staple food for North African populations. The aim of this study was to analyze populations of Aspergillus section Flavi from local wheat based on aflatoxins (AFs), cyclopiazonic acid (CPA) and sclerotia production, and also to evaluate AFs-contaminated wheat collected from two different climatic regio...

actinomycete; new angucyclinone; Streptosporangium; structure elucidation

The fungus Fusarium langsethiae, exclusively described in Europe at present, seems to have taken the place of other Fusarium species in barley fields over the last 5 years. It has proved to be a highly toxic type-A trichothecene producer (T-2 and HT-2 toxins). The aim of this work was to study the ecotoxinogenesis of this fungus the better to ident...

Essential oils of four different Eucalyptus species (Eucalyptus salubris, Eucalyptus salmonophloia, Eucalyptus oleosa, and Eucalyptus gracilis) grown in southern Tunisia were screened for their antioxidant and antimicrobial properties as well as their chemical compositions. According to gas chromatography-flame ionization detection and gas chromato...

Three new antibiotics were isolated from the fermentation broth of Saccharothrix algeriensis NRRL B-24137 and characterized as the dithiolopyrrolone derivatives valerylpyrrothine (1), isovalerylpyrrothine (2), and formylpyrrothine (3) as well as the known antibiotic aureothricin. The production of the dithiolopyrrolone derivatives was induced by ad...

Two novel halophilic actinomycetes, strains AH35 and AH10, isolated from saline soils obtained from the Algerian Sahara, were subjected to polyphasic taxonomic characterization. The strains showed good growth in medium containing 7, 10 and 15% NaCl with growth at temperatures of 28–42°C. The organism produced light grey-green aerial mycelium with r...

The primary goal of this research was to assess the biotransformation of zearalenone (ZEA), an oestrogenic mycotoxin, into ZEA-sulfate by some Aspergillus section Nigri isolates. A. niger isolates were shown to be able to convert ZEA after 72 h of incubation at different ZEA concentrations (5 to 150 μg/ml). The product formula corresponding to ZEA-...