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Acourene S.,Station of Algerian National Institute of Agricultural Research | Ammouche A.,National Institute of Agronomy
Journal of Industrial Microbiology and Biotechnology | Year: 2012

The present study deals with submerged ethanol, citric acid, and α-amylase fermentation by Saccharomyces cerevisiae SDB, Aspergillus niger ANSS-B5, and Candida guilliermondii CGL-A10, using date wastes as the basal fermentation medium. The physical and chemical parameters influencing the production of these metabolites were optimized. As for the ethanol production, the optimum yield obtained was 136.00 ± 0.66 g/l under optimum conditions of an incubation period of 72 h, inoculum content of 4% (w/v), sugars concentration of 180.0 g/l, and ammonium phosphate concentration of 1.0 g/l. Concerning citric acid production, the cumulative effect of temperature (30C°), sugars concentration of 150.0 g/l, methanol concentration of 3.0%, initial pH of 3.5, ammonium nitrate concentration of 2.5 g/l, and potassium phosphate concentration of 2.5 g/l during the fermentation process of date wastes syrup did increase the citric acid production to 98.42 ± 1.41 g/l. For the production of α-amylase, the obtained result shows that the presence of starch strongly induces the production of α-amylase with a maximum at 5.0 g/l. Among the various nitrogen sources tested, urea at 5.0 g/l gave the maximum biomass and α-amylase estimated at 5.76 ± 0.56 g/l and 2,304.19 ± 31.08 μmol/l/ min, respectively after 72 h incubation at 30C°, with an initial pH of 6.0 and potassium phosphate concentration of 6.0 g/l. © Society for Industrial Microbiology and Biotechnology 2011. Source

Bendifallah L.,University of Boumerdes | Louadi K.,University of Mentouri Constantine | Doumandji S.,National Institute of Agronomy
Journal of Apicultural Science | Year: 2013

Coriander Coriandrum sativum L. (Apiaceae) is a year-round condiment and aromatic Mediterranean plant. It is cultivated in several countries in North Africa, in Europe, and Western Asia. In the El Harrach area of Algiers, the insect fauna visiting crop flowers includes Diptera (Syrphidae), Coleoptera, and Hymenoptera such as Chrysididae, Vespoidea, and Apoidea (Bees). The latter super-family comprises the majority of insect pollinators. Visiting bees belong to four families: Apidae, Andrenidae, Halictidae, and Colletidae. The main visitors are honeybees and six species of Andrenidae: Andrena flavipes, Andrena thoracica, Andrena lagopus, Andrena bimaculata, Andrena discors, and Andrena cinerea elliptica. The three species Andrena lagopus, Andrena bimaculata, and Andrena cinerea elliptica have 100% pollinating visits while Apis mellifera has only 63%. Andrena cinerea elliptica is the most frequent and the most abundant species. Source

Irie M.,University of Tsukuba | Tarhouni J.,National Institute of Agronomy
Journal of Physics: Conference Series | Year: 2015

The industries related to the ceramics such as construction bricks, pottery and tile are the important sectors that cover the large part of the working population in Tunisia. The raw materials, clay or silt are excavated from opencast site of limestone clay stratum. The opencast site give the negative impact on landscape and environment, risks of landslide, soil erosion etc. On the other hand, a most serious problem in water resource management, especially in arid land such as Tunisia, is sedimentation in reservoirs. Sediment accumulation in the reservoirs reduces the water storage capacity. The authors proposed the exploitation of the sediment as raw material for the ceramics industries in the previous studies because the sediment in Tunisia is fine silt. In this study, the potential of the water reservoirs in Tunisia as the resource of the raw material for the ceramics industries is estimated from the sedimentation ratio in the water reservoirs. Source

Marrakchi R.,University of Carthage | Marrakchi R.,University of Montreal | Chouchani C.,University of Carthage | Cherif M.,National Institute of Agronomy | Ramotar D.,University of Montreal
Biochemistry and Cell Biology | Year: 2011

In Saccharomyces cerevisiae, rapamycin exposure inhibits the target of rapamycin (TOR) signaling pathway, causing a profound alteration in the transcription pattern of many genes, including those involved in ribosome biogenesis and nutritional changes. Deletion of the RRD1 gene encoding a peptidyl prolyl isomerase resulted in mutants that are resistant to rapamycin. These rrd1Δ mutants are unable to efficiently downregulate genes such as ribosomal protein genes, or to upregulate genes involved in diauxic shift. It is believed that the isomerase function of Rrd1 plays a role in changing the transcriptional profile upon rapamycin exposure. Herein, we set out to search for genes that when deleted in the rrd1Δ mutant would suppress the rapamycin-resistant phenotype. The analysis revealed that deletion of the SGS1 gene in the rrd1Δ mutant partially suppresses the rapamycin-resistant phenotype of the single rrd1Δ mutant. SGS1 encodes a helicase that functions in many biological processes, including transcriptional regulation. We further show, and for the first time, that Sgs1 is rapidly lost in the parent cells in response to rapamycin, but not by other agents. Interestingly, Sgs1 reduction was completely blocked in the rrd1Δ mutant, suggesting that Rrd1 is required to mediate this process. Genes such as PUT4 and HSP42, known to be upregulated in the parent in response to rapamycin, were not induced in the rrd1Δ mutant if the SGS1 gene was deleted. Since Sgs1 plays a role in transcriptional regulation, we propose that it acts as a repressor of a subset of rapamycin responsive genes. Thus, the observed Rrd1-dependent reduction in Sgs1 level may promote expression of specific classes of genes in response to rapamycin. © 2011 Published by NRC Research Press. Source

Benabderrahim M.A.,Institute of Arid Lands IRA | Hamza H.,Institute of Arid Lands IRA | Haddad M.,Institute of Arid Lands IRA | Ferchichi A.,National Institute of Agronomy
Plant Biosystems | Year: 2015

This work investigated the variability in drought tolerance under arid conditions of Mediterranean alfalfa genotypes with the overall aim to assess the main criteria that are associated with the relative tolerance and to discover the most tolerant ecotypes. For this, 16 alfalfa genotypes originating from seven countries of the Mediterranean basin were tested in an experimental station in south of Tunisia. The trial was conducted under two irrigation treatments. The first was normally irrigated by providing an amount of water corresponding to the potential evapotranspiration of the crop, and in the second with water deficit which was applied by stopping the irrigation during 8 weeks in summer. A significant decrease was observed under water deficit for biomass production, leaf stem ratio and water use efficiency. The sensitive index, in stress treatment, varies between 13.8% and 46.2% for dry yield. Results showed that some genotypes exhibited high-forage yield potential even in the presence of stress, mainly Amerist, Sardi10 and Siriver. Proline accumulation in leaves was greater in water-stressed plants, while the K+ osmo-regulatory role was not definite. High biomass production, accumulation of proline and constancy of K+ in leaves are the most important criteria for tolerant alfalfa. © 2013,Società Botanica Italiana. Source

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