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Articles by Noura El-Ahmady El-Naggar
Total Records ( 9 ) for Noura El-Ahmady El-Naggar
  A.A. Sherief , Noura El-Ahmady El-Naggar and Sarah Shawky Hamza
  Screening of cellulolytic activity by ten fungal isolates recovered from soil and agricultural wastes indicated that Aspergillus fumigatus showed the highest cellulolytic activity, under solid-state fermentation (SSF) using rice straw as substrate. Optimization of fermentation conditions showed that highest cellulolytic enzymes production on 4th day at pH 5.5 and at 40°C. The production of enzymes was reached its maximal value at 5.0 g/flask of rice straw. Avicellase, endoglucanase and CMCase productivity were highly increased by addition of L-asparagine, NH4Cl and NaNO3, respectively as N-sources to the fermentation medium. Maximum activities of avicellase and endoglucanase were recorded at inoculum size of 2.5 mL, while maximum activity of CMCase was detected at inoculum size of 0.5 mL. The influence of various physico-chemical factors “incubation period, temperature, pH and substrate concentration” on enzyme activity was also investigated. The half life time of avicellase, endoglucanase and CMCase at 60°C were 67.8, 79.1 and 96.5 min, respectively. Rice straw hydrolysate obtained through enzymatic hydrolysis of rice straw was used as a substrate for bioethanol production. Maximum ethanol production by Saccharomyces cereviseae using dilute acid pretreated rice straw hydrolysate with initial soluble sugar 4.1055±0.0146% was recorded after 48 h of fermentation (2.26424±0.0206%).
  Noura El-Ahmady El-Naggar , E.A. Metwally , A.B. El-Tanash and A.A. Sherief
  Forty five soil samples from different sites of non-cultivated soil, salt marshes and rhizosphere of some wild and cultivated soils collected from seven governorates of Egypt were used as local source for isolation of some inulinolytic fungi. Forty six fungal species belonging to three sub-divisions of Zygomycotina, Ascomycotina and Deutromycotina were identified. Eight unknown filamentous fungi characterized by their black reverse color on PDA medium and Czapek agar plates were recorded. Frequency of occurrence indicates that Aspergillus foetidus var. pallidus (frequency 52.2%) was the most dominant followed by A. sclerotiorum (39.1%). All fungi were able to grow on medium containing sugar cane bagasse and Jerusalem artichoke tubers powder (1:1). No significant correlation observed between the fungal growth, liberated soluble protein and inulinase activities. Inulinase activity indicate that Aspergillus foetidus var. pallidus (564.71±1.22 Ugds-1), A. sclerotiorum (534.78±1.37 Ugds-1), Emericella nidulans (495.73±3.85 Ugds-1) and A. aculeatus (444.37±2.37 Ugds-1) were the most active fungal species able to produce a considerable amount of enzyme activity.
  Attiya Hamed Mohamedin , Noura El-Ahmady El-Naggar , Abd El-Dayem A. Sherief and Suzan Mohamed Hussien
  The newly isolated actinomycetes strain namely M19 was isolated from marine sediment and exhibited antibacterial activity against multidrug-resistant Staphylococcus epidermidis. It was identified on the basis of morphological, cultural, physiological and biochemical properties, together with 16S rRNA sequence as Streptomyces psammoticus strain M19 and sequencing product was deposited in the GenBank database under accession number KT160249. Fifteen factors including starch, KNO3, K2HPO4, yeast extract, NaCl, MgSO4, CaCO3, FeSO4, pH, temperature, agitation speed, medium volume, inoculum size, inoculum age and fermentation time had been examined for their significance on the production of bioactive metabolites using Plackett-Burman design. Out of the fifteen factors; agitation speed, yeast extract, NaCl and KNO3 were selected due to their significant effects on the production of bioactive metabolites and the optimal levels of these variables and the effect of their interactions on bioactive metabolites production were determined by using central composite design. As a result, culture conditions and a medium of the following formula were predicted to be the optimum for production of extracellular bioactive metabolites in the culture filtrate of Streptomyces psammoticus strain M19: Starch 20 g, KNO3 1.5 g, K2HPO4 0.5 g, yeast extract 0.2 g, NaCl 0.5 g, MgSO4 0.1 g, CaCO3 3 g, FeSO4 0.01 g, pH 6.5, temperature 25°C, agitation speed (125 rpm min‾1), medium volume 75 mL, inoculum size 2% (v/v), inoculation age 48 h and fermentation time 5 days. The antagonistic activity produced from the optimized culture conditions against multidrug-resistant Staphylococcus epidermidis, showed about 1.37 fold increase than that obtained from the un-optimized medium.
  Noura El-Ahmady El-Naggar , Ashraf A. El-Bindary and Noura Salah Nour
  Streptomyces anulatus NEAE-94, an antagonistic actinomycete newly isolated from Egyptian soil, exhibited a broad antimicrobial spectrum against several microorganisms including multidrug-resistant Staphylococcus aureus, E. coli, Bacillus subtilis, Pseudomonas aeruginosa and Candida albicans. Fifteen factors (starch, KNO3, K2HPO4, yeast extract, NaCl, MgSO4, CaCO3, FeSO4, pH, temperature, agitation speed, medium volume, inoculum size, inoculum age and fermentation time) were examined for their significances on production of antimicrobial metabolites using Plackett-Burman design. Among the variables screened, agitation speed, inoculum size and inoculum age had significant effects on antimicrobial activities production. These factors were further optimized using Box Behnken statical design.The optimal conditions achieved were high level of agitation speed (250 rpm min-1), middle level of inoculum size (4%) and low level of inoculum age. The Antagonistic activity produced from the optimized culture conditions against multidrug-resistant Staphylococcus aureus, showed about two fold increase than that obtained from the un-optimized medium. As a result, a medium of the following formula was predicted to be the optimum for producing an extracellular antimicrobial metabolites in the culture filtrate of Streptomyces anulatus NEAE-94 L-1: Starch 20 g, KNO3 2 g, K2HPO4 0.5 g, NaCl 0.1 g, MgSO4.7H2O 0.1 g, CaCO3 3 g, FeSO4.7H2O 0.01 g, pH 6.5, temperature 25°C, agitation speed 250 rpm min-1, medium volume 75 mL, inoculum size 4%,v/v, inoculum age 60 h and fermentation period 5 days.
  Noura El-Ahmady El-Naggar
  One hundred and thirty actinomycetes soil-isolates were screened for their uricase activity. The most promising isolate, strain NEAE-25, was selected and identified on the basis of morphological, cultural, physiological and biochemical properties, together with 16S rRNA sequence as Streptomyces rochei NEAE-25 and the sequencing product was deposited in the database of GenBank under accession number HQ889312. The optimization of different process parameters for uricase production by Streptomyces rochei NEAE-25 and its validation using Plackett-Burman experimental design and response surface methodology was carried out during the present study. Fifteen variables were screened using Plackett-Burman experimental design. The most significant positive independent variables affecting enzyme production (incubation time, medium volume and uric acid concentration) were further optimized by central composite design. The maximum uricase production by Streptomyces rochei NEAE-25 after central composite design was 47.49 U mL–1 with a three-fold increase as compared to the unoptimized medium (16.1 U mL–1).
  Ragaa A. Hamouda , Noura El-Ahmady El-Naggar and Ghada Wagih Abou-El-Seoud
  Background and Objective: The growth rate, primary and secondary metabolites are influenced by nitrogen concentration of media. This study aimed to determine the effect of different concentrations of KNO3 as a source of nitrogen on the growth, phytochemical components, cholesterol reduction, antioxidant and antibacterial activities of the green alga, Scenedesmus obliquus (S. obliquus). Materials and Methods: Scenedesmus obliquus was cultured in Kuhl’s medium and KNO3 was added with different concentrations in the medium at different concentration (0.12, 0.75, 1.5, 2.25 and 3 g L–1). The effect of different five concentrations of nitrogen on protein and carbohydrates was determined. Antioxidant activity, total phenolic content (TPC) of alga extracts, cholesterol reduction and antibacterial activity were evaluated. The data analyses were carried out using SPSS software version 16. Results: The results revealed that the best KNO3 concentration for algal growth and carbohydrate content is1.5 g L–1. Meanwhile, the high lipid content was obtained with KNO3 starvation. Medium containing 0.75 g L–1 of KNO3 has the highest effect on the protein production of S. obliquus. The contents of dry alga extracted with chloroform: methanol and the extracted contents were determined by GC/MS chromatogram; the major contents were 5-Hydroxymethylfurfural followed by hexadecanoic acid (palmitic acid), cis-9-octadecenoic acid (oleic acid) and hexadecanoic acid and methyl ester, respectively. Conclusion: Potassium nitrate limitation caused the highest effect on the total phenol content (TPC), increased antioxidant capacity, cholesterol reduction activity and also antibacterial activity against Staphylococcus aureus and Escherichia coli.
  Noura El-Ahmady El-Naggar , Mervat H. Hussein , Sami A. Shaaban-Dessuuki and Shimaa R. Dalal
  Background: Due to high nutritional value, natural pigments and antioxidant activity, Chlorella vulgaris is used as a health food, feed supplement, as well as in the pharmaceutical and cosmetics industry. It contains polysaccharides, proteins, lipids, antioxidants, vitamins, carotenoids, immunostimulator compounds and minerals. A statistical approach has been employed for which a Plackett-Burman design is used for identifying significant variables influencing polysaccharides production by Chlorella vulgaris. Materials and Methods: Ten different independent variables including mannitol, sodium acetate, potassium citrate, NaNO3, K2HPO4, MgSO4, CaCl2.2H2O, Na2CO3, inoculum size and inoculum age were screened by Plackett-Burman experiment and High Performance Liquid Chromatography (HPLC) was used to characterize the compounds in Chlorella vulgaris polysaccharides. Results: Among the variables screened, mannitol, sodium acetate and inoculum age had significant effects on polysaccharides production. The HPLC chromatograms indicated that Chlorella vulgaris extract contain fructose, glucose, maltose and lactose with concentration of 13.259, 283.027, 26.387 and 25.489 mg g–1 dry weight, respectively. Conclusion: The results indicate that this alga contains high amount of glucose which can use in different applications.
  Husain A. El-Fadaly , Noura El-Ahmady El-Naggar and El-Sayed M. Marwan
  An oleaginous yeast strain, Cryptococcus curvatus NRRLY-1511 was used for the production of single cell oil (SCO) using a low cost cultivation medium containing beet molasses and corn gluten meal as carbon and nitrogen sources. Obtained results showed that 125 and 0.130 g L-1 showed to be the optimum concentrations for carbon and nitrogen, respectively. In addition, 28°C, 72 h, 5.5, 200 rpm were the favorable values of growth temperature, incubation period, pH value of cultivation medium and agitation speed, respectively. The extracted lipids were mainly 30.68% linoleic acid (C18:2), 22.66% oleic acid (C18:1) and 16.74% palmitic acid (C16:0). Furthermore, the GC analysis also showed that the total saturated fatty acids (n = 9) represented 41.96% while the value of the total unsaturated fatty acids (n = 6) was 58.04%. These results giving possibility to use such this yeast strain to produce SCO in a low cost medium from economic point of view.
  W.I.A. Saber , Noura El-Ahmady El-Naggar and Samia AbdAllah AbdAl-Aziz
  Two sequenced screening trials were carried out on 21 fungi isolated from decayed rice straw. The aim was to obtain fungal isolates with cellulolytic activity and rock phosphate (RP) solubilization ability for employing them in organic acid production from rice or wheat straw. Penicillium, Aspergillus and Stachybotrys were the predominant isolated genera. On the base of cellulase (filter paperase, carboxymethyl cellulase and β-glucosidase) production, RP solubilization efficiency and antagonism tests, two fungi were selected and molecularly identified as A. niger GU 295947 and P. chrysogenum GU 295948. Under solid-state fermentation (SSF) conditions of rice straw with RP, the maximum cellulase production and RP solubilization were recorded after 4 weeks incubation in the presence of 75 mg P2O5 from RP and 7.5% (v/w) fungal inoculum. Applying these fermentation conditions on rice and wheat straw, using individual or dual inoculation of both fungi led to more than 40% loss in the weight of fermented straw, this was accompanied with the releasing of glucose and soluble phosphorus in the hydrolysate of fermented straw. Using high-performance liquid chromatography, the resulted organic acids by A. niger GU 295947 and/or P. chrysogenum GU 295948 in the hydrolysate of SSF were investigated. Acetic, ascorbic, citric, formic, itaconic, levulinic, maleic, oxalic and succinic acids were detected. Their presence and concentrations were varying according to the substrate and the microorganism. The most noticeable thing was the broadspectrum varieties and the higher concentrations of produced organic acids when rice or wheat straw was used in combination with RP. Oxalic acid was the highest (40.0 mg g-1 straw) detected organic acid in the hydrolysate of fermented straw with RP by P. chrysogenum GU 295948. This study suggests production of organic acids especially, oxalic and succinic acids as the major organic molecules by such fermentation.
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