Mohamed A. Abdel-Naby

National Research Center, Egypt | NRC · Department of Chemisty of Natural and Microbial Products

Background: Calf rennet is considered the traditional source of milk clotting enzyme (MCE). However, increasing cheese consumption with decreasing the calf rennet supply had encouraged the quest for new rennet alternatives. The purpose of this study is to acquire more information about the catalytic and kinetic properties of partially purified Bac...

Milk clotting enzyme (MCE) from Bacillus circulans 25 was immobilized by covalent binding, ionic binding and entrapment methods using various carriers. MCE covalently immobilized on activated chitosan polymer with the bifunctional agent glutaraldehyde (Ch-MCE) exhibited highest immobilization yield (74.6 %). Comparing to the native MCE, Ch-MCE exhi...

The proteolytic strain Bacillus cereus-S6-3was subjected tomutagenic treatments viz. UV irradiations andmethyl methane sulfonate (MMS). The obtained mutant strain, B. cereus-S6-3/UM90 showed 1.34 fold over the parent strain. Molecular characterization of proteases from the parent (PP/S6-3) and mutant (PM/UM90) strains indicated that they were consi...

The production of dextranase was investigated in static cultures of Penicillium funiculosum 258, Maximal enzyme productivity was attained at pH 8.0. with 3.5% (w/v) dextran (MW. 260000) as carbon source, NaN0 3 (1%. w/v) and yeast extract (0.2%, w/v) as nitrogen source, 0.4% (w!v) K 2 HP0 4 and 0.06% (w/v) MgS0 4. It was possible to increase the pr...

Microbial proteases are important group of enzymes that are widely used in pharmaceutical, food agriculture industries and bioremediation process. Present study aimed to isolate a new source of protease producing Bacillus and increase the enzyme produced by optimization of some culture conditions. Obtained results revealed that out of 153 bacterial...

Production of a celtobiase-rich preparation by Aspergillus niger 1 was achieved using water hyacinth cellulose as the sole carbon source in the culture medium. Production of cellobiase, carboxymethylcellulase (CMC-ase) and filter paper (FPI-celiulase was favoured by controlling the pH of the culture medium during fermentation at 5.0. Sodium citrate...

The production of extracellular pullulanase by Bacillus licheniformis NRC22 was investigated using different fermentation modes. In batch culture maximal enzyme activity of 18 U/ml was obtained after 24 h of growth. In continuous fermentation by the free cells, maximal reactor productivity (4.15 KU/l/h) with enzyme concentration of 14.8 U/ml and sp...

The proteolytic strain Bacillus cereus-S6-3 was subjected to mutagenic treatments viz. UV irradiations and methyl methane sulfonate (MMS). The obtained mutant strain, B. cereus-S6-3/UM90 showed 1.34 fold over the parent strain. Molecular characterization of proteases from the parent (PP/S6-3) and mutant (PM/UM90) strains indicated that they were co...

The agricultural and industrial wastes are environmental pollutants. So, there is an increasing demand for more efficient exploitation of these wastes and their conversion into useful products. Recently, the limited availability of calf rennet led to a search for rennet substitutes for cheese manufacture. In this study, Bacillus subtilis subsp. sub...

The agricultural and industrial wastes are environmental pollutants. So, there is an increasing demand for more efficient exploitation of these wastes and their conversion into useful products. Recently, the limited availability of calf rennet led to a search for rennet substitutes for cheese manufacture. In this study, Bacillus subtilis subsp. sub...

Laccase enzyme from Polyporus durus ATCC 26726 was immobilized on nanoporous Zeolite-X (ZX), with 83% immobilization yield. The immobilization process protected laccase against pH and temperature changes. The activation energy was lowered after immobilization. Compared to the free enzyme the immobilized enzyme displayed higher K m value and lower V...

The production of milk-clotting enzyme (MCE) by free and immobilized Bacillus circulans 25 cells was investigated. The investigation evaluates cell immobilization through entrapment and covalent binding to different carriers. B. circulans 25 cells immobilized covalently via glutaraldehyde (cross-linker) to natural wool exhibited higher effectivenes...

Background and objective In textile processing, 50% of the dye is released as effluent which is considered as hazardous contaminant that threats environment and human life. The use of laccase enzyme for dye decolorization is cost effective and environmentally friendly. So, the main objective of the present study is the production of microbial lacca...

Milk clotting enzyme (MCE) produced by Bacillus subtilis KU710517 was conjugated to several activated polysaccharides. Among all the conjugates, the enzyme conjugated with polyethylene glycol (PEG) exhibited the highest retained activity (551U/mg protein) with a recovered activity of 95.3%. The activation energy of PEG-conjugated enzyme was calcula...

HCV infection is a serious public health problem and a leading cause of chronic liver disease. It affects nearly 3% of the world's population with an associated high mortality. Egypt has the highest prevalence of HCV infection in the world (estimated at >10%). Peg-IFN-α and RBV are the most widely used therapy for HCV. Unfortunately, the rate of SV...

Laccase enzyme from Polyporus durus ATCC 26726 was immobilized on nanoporous Zeolite-X (ZX), with 83% immobilization yield. The immobilization process protected laccase against pH and temperature changes. The activation energy was lowered after immobilization. Compared to the free enzyme the immobilized enzyme displayed higher Km value and lower Vm...

Bacillus pumilus FH9 keratinase was purified to homogeneity with a 59.9% yield through a series of three steps. The purified enzyme was a monomeric protein with a molecular mass around 50 kDa and containing 7.3% carbohydrates. The pure B. pumilus FH9 keratinase was optimally active at pH 9.0 and 60 °C. The calculated activation energy for keratin h...

Bacillus stearothermophilus alkaline protease was conjugated to several oxidized polysaccharides of different chemical structure. The conjugates were evaluated for the kinetic and thermodynamic stability. The conjugated enzyme with oxidized pectin had the highest retained activity (79.5%) and the highest half-life (T1/2) at 50 °C and pH 9.0. Compar...

Five agro-industrial wastes (AIW) were selected to verify their potential as low cost substrate to produce α-amylase enzyme by bacterial strains using solid state fermentation (SSF) and submerged state fermentation (SMF). Among the AIW used strawberry leaves and watermelon rind produced the maximum α-amylase production under SMF by B.subtilis and B...

Mucor circinelloides isolate F6-3-12 was selected out of three fungal isolates that can utilize tannic acid as substrate. The fungus was identified by phenotypic analysis and 18S rRNA gene sequencing. Extracellular tannase was produced by solid-state fermentation (SSF) and submerged fermentation (SmF) from plants known for their high tannin content...

Among all the tested bacteria the marine sponge Pseudoceratina arabica isolated bacterium (isolate I) showed the highest milk-clotting activity. This isolate was used for MCE production throughout this study and it was identified as Bacillus subtilis KU710517. Maximum enzyme productivity (581.8 U/ml) and maximum MCE/ caseinase ratio were obtained u...

Background: Fistula-in-ano (FIA) in infants differs, in several ways, from FIA in adults. The current review aims to assess FIA in infants less than 2 years old and to illustrate the outcome of different treatment modalities described in the literature. Methods: An organized search of the English literature over the past 25 years was conducted a...

Tannase (EC.3.1.1.20) from Aspergillus oryzae was purified using ammonium sulphate precipitation (75%), gel filtration chromatography through Sephadex G-100, and G-200. The purified enzyme was monomeric protein with a molecular mass of 106 kDa. The activation energy for tannic acid hydrolysis was 32.6 kJ mol−1 and its temperature quotient (Q10) was...

Chitinase (EC 3.2.1.14) was produced from the culture filtrate of marine-derived Aspergillus terreus and purified by 65% ammonium sulphate precipitation, followed by gel filtration on Sephadex G-100 and DEAE-Sephadex A-50 ion exchange chromatography, with 5.16-fold of purification and specific activity of 182.08U/mg protein. The molecular weight of...

Bacillus pumilus FH9 keratinase was covalently coupled to several oxidized polysaccharides. The conjugates were evaluated for the retained activity, kinetic and thermodynamic stability. Among all preparations, the conjugated enzyme with oxidized pectin had the highest recovered activity (71.75%) and the highest thermal stability at 60 • C (t 1/2 =...

Microbial proteases are important group of enzymes that are widely used in pharmaceutical, food agriculture industries and bioremediation process. Present study aimed to isolate a new source of protease producing Bacillus and increase the enzyme produced by optimization of some culture conditions. Obtained results revealed that out of 153 bacterial...

Abstract: The aim of this research was to find a new microbial source for chitosanase production. Optimization of the fermentation conditions and medium compositions to maximize the enzyme production using one variable at a time technique, characterization of the crude enzyme as well as studying the ability of this enzyme to produce chitooligosacch...

Bacillus pumilus FH9 keratinase was covalently coupled to several oxidized polysaccharides. The conjugates were evaluated for the retained activity, kinetic and thermodynamic stability. Among all preparations, the conjugated enzyme with oxidized pectin had the highest recovered activity (71.75%) and the highest thermal stability at 60°C (t1/2=333mi...

HCV infection is a serious public health problem and a leading cause of chronic liver disease. It affects nearly 3% of the world's population with an associated high mortality. Egypt has the highest prevalence of HCV infection in the world (estimated at >10%). Peg-IFN-α and RBV are the most widely used therapy for HCV. Unfortunately, the rate of SV...

Bacillus amyloliquefaciens cyclodextrin glucosyltransferase (CGTase) was immobilized on 35 supports by different methods of immobilization. The immobilized enzymes were prepared by physical adsorption on chitin, ionic binding onto Amberalite IRA-45, covalent binding on Duolite XAD761, and entrapment in polyacrylamide had the highest recovered activ...

Phytochemical screening of dried leaves and fruits of Juniperus phoenicea growing in Egypt revealed the presence of essential oil, carbohydrates, sterols and/or triterpenes, and flavonoids. The carbohydrates of the edible part, fruits, were investigated by high-performance liquid chromatography while the carbohydrates in the leaves were investigate...

Water hyacinth was pretreated, under variable conditions, with NaOH, alkaline H2O2, peracetic acid and sodium chlorite. Combined pretreatments included sodium chlorite with each of NaOH, alkaline H2O2 and peracetic acid. Combined pretreatment with 0.1% NaClO2 for 1h at 100°C and peracetic acid at 100°C for 15min afforded the most promising sample....

The production of extracellular pullulanase by Bacillus licheniformis NRC22 was investigated using different fermentation modes. In batch culture maximal enzyme activity of 18 U/ml was obtained after 24 h of growth. In continuous fermentation by the free cells, maximal reactor productivity (4.15 KU/l/h) with enzyme concentration of 14.8 U/ml and s...

The objective of this study was to enhance the production of cyclodextrin glucanotransferase (CGTase) produced by a local isolate Bacillus cereus NRC7. In batch culture, maximal CGTase activity (69·0 U ml(-1)) was reached after 24-h incubation period. In continuous production of CGTase by the free cells of B. cereus NRC7, maximal reactor productivi...

In this study two local isolates Aspergillus japonicus and Aspergillus oryzae were investigated for tannase production on synthetic medium containing tannic acid as sole carbon source. Optimizations of intracellular tannase production at different culture conditions using batch and submerged fermentation techniques were studied. The highest levels...

Forty mongrel dogs were used in this study for induction of periodontal disease by placing subgingival silk ligatures affecting maxillary and mandibular premolar teeth during a 12-month period. Experimental premolar teeth received monthly clinical, radiographic, and histometric/pathologic assessments. The results demonstrated significant increases...

Different feather degrading bacteria were isolated from soil using an enrichment technique with feather as a sole carbon and nitrogen source. A strain with high keratinolytic activity was identified as Bacillus pumilus FH9 using sequencing of the 16SrDNA gene. Phylogenic analysis showed that the strain was most similar to B. pumilus AF526896 and AF...

The study of the production of the enzyme analyst for the protein in alkaline media by six strains of bacteria and characterized strain Bacillus stearothrmophilus the highest productivity of the active enzyme (14.9 units / ml) using the technique farms shaky, have been identified the most suitable conditions for the production of the enzyme by stra...

The functional digital testing is defined as a black and white test according to N. Nagi et al.(1998) and B. Vinnakota(1998) by other words, it can determine faulty and non faulty boards. But the analog faults are not. The faulty and non-faulty are relatively defined depending on tolerance allowed for non-faulty boards. In this paper, we introduce...

Xylanase from Aspergillus tamarii was covalently immobilized on Duolite A147 pretreated with the bifunctional agent glutaraldehyde. The bound enzyme retained 54.2% of the original specific activity exhibited by the free enzyme (120 U/mg protein). Compared to the free enzyme, the immobilized enzyme exhibited lower optimum pH, higher optimum reaction...

Xylanase from Aspergillus tamarii was covalently immobiliz ed on Duolite A147 pretreated with the bifunctional agent glu taraldehyde. The bound enzyme retained 54.2 % of the original specific activity exhibited by the free enzyme (120 U/mg pro tein). Compared to the free enzyme, the immobilized enzyme exhibited lower optimum pH, higher optimum reac...

Immunohistochemistry of c-Fos protein was performed to study changes in neuronal activity in discrete brain areas of mice repeatedly treated with phencyclidine (PCP) showing enhancement of immobility in the forced swimming test, this behavioral change being considered as avolition, which is one of negative symptoms of schizophrenia. Repeated treatm...

The immobilized cells of five bacterial cultures on different carriers were investigated for the production of cyclodextrin glucosyltransferase (CGTase). The entrapped cells of Bacillus amyloliquefaciens in calcium alginate showed the highest enzyme activity (70.8Uml−1). The enzyme production with respect to alginate concentration, bead diameter, a...

The electrical, optical and photoelectric measurements of Mg xZn1-xTe alloys indicate an increasing compensation with the increase of Mg concentration, and the donor impurities are attributed to P. The optical absorption spectrum exhibits a peak suited at 1.06 eV, independent of composition. Supportive evidence is obtained for the assignment of thi...

Cellobiase from Aspergillus niger was glycosylated by covalent coupling to cyanogen bromide activated dextran. The conjugated enzyme retained 62% of the original specific activity exhibited by the native cellobiase. The optimum pH as well as the pH stability of the conjugated form remain almost the same as for the native enzyme. Compared to the nat...

Tannase enzyme from Aspergillus oryzae was immobilized on various carriers by different methods. The immobilized enzyme on chitosan with a bifunctional agent (glutaraldehyde) had the highest activity. The catalytic properties and stability of the immobilized tannase were compared with the corresponding free enzyme. The bound enzyme retained 20·3% o...

Cyclodextrin glucosyltransferase from Paenibacillusmacerans NRRL B-3186 was immobilized on aminated polyvinylchloride (PVC) by covalent binding with a bifunctional agent (glutaraldehyde). The immobilized activity was affected by the length of the hydrocarbon chain attached to the PVC matrix, the amount of the protein loaded on the PVC carrier, and...

The production of dextranase was investigated in static cultures of Penicillium funiculosum 258. Maximal enzyme productivity was attained at pH 8.0, with 3.5% (w/v) dextran (MW, 260 000) as carbon source, NaNO3 (1%, w/v) and yeast extract (0.2%, w/v) as nitrogen source, 0.4% (w/v) K2HPO4 and 0.06% (w/v) MgSO4. It was possible to increase the produc...

Davidenko's efficient method is presented and implemented for accurately finding the complex roots (the complex propagation constants) of the dispersion equation (analytic function with complex variable) of moving waveguides. Numerical results are illustrated for various physical parameters, and are compared with an approximate perturbation approac...

We present here two methods of analysis of the complex moving waveguide. One approach is a numerical technique based on Davidenko's method, the other is a perturbation method. Numerical results by Davidenko's method are compared with these obtained from the perturbation method. It is found that the results of the perturbation method are in a good a...

Three cellobiases, here called cellobiase A, B, and C, from the culture filtrate of Aspergillus niger A20, were purified by precipitation with ammo-nium sulphate, gel filtration through Sephadex G-75, and column chromatography of DEAE-cellulose. The purified enzymes were homogeneous on polyacrylamide disk electrophoresis. The mol wt of the purified...

Bacillus subtilis I (α-amylase was immobilized on different carriers by different methods of immobilization. The immobilized enzymes were prepared by physical adsorption on aminoalkylsilane-alumina (AS-alumina), ionic binding onto DEAE-cellulose, covalent binding on chitin, and entrapment in polyacrylamide had the highest activities. The specific a...

Sputter deposition has become a widely used technique for fabrication of metal-semiconductor junction devices. In the present paper, the electrical properties of radio frequency (RF) sputtered In-ZnTe Schottky diodes have been measured over the temperature range 100-300 K. The transport properties of the junction were investigated by measuring the...

M.A. ABDEL-NABY, AA SHERIF, A.B. EL-TANASH AND AT MANKARIOS. 1999. Tannase enzyme from Aspergillus oryzae was immobilized on various carriers by different methods. The immobilized enzyme on chitosan with a bifunctional agent (glutaraldehyde) had the highest activity. The catalytic properties and stability of the immobilized tannase were compared wi...

M.A. ABDEL-NABY, AA SHERIF, A.B. EL-TANASH AND AT MANKARIOS. 1999. Tannase enzyme from Aspergillus oryzae was immobilized on various carriers by different methods. The immobilized enzyme on chitosan with a bifunctional agent (glutaraldehyde) had the highest activity. The catalytic properties and stability of the immobilized tannase were compared wi...

M.A. ABDEL-NABY, AA SHERIF, A.B. EL-TANASH AND AT MANKARIOS. 1999. Tannase enzyme from Aspergillus oryzae was immobilized on various carriers by different methods. The immobilized enzyme on chitosan with a bifunctional agent (glutaraldehyde) had the highest activity. The catalytic properties and stability of the immobilized tannase were compared wi...

Three cellobiases, here called cellobiase A, B, and C, from the culture filtrate of Aspergillus niger A20, were purified by precipitation with ammo-nium sulphate, gel filtration through Sephadex G-75, and column chromatography of DEAE-cellulose. The purified enzymes were homogeneous on polyacrylamide disk electrophoresis. The mol wt of the purified...

This paper presents two methods of analysis of the complex moving waveguide. One approach is a numerical technique based on Davidenko's method, the other is a perturbation method. It is clear that if one wants to obtain more accurate results over a wide range it is necessary to develop numerical techniques capable for solving lossy waveguides that...

The production of alkaline protease was investigated in submerged culture of Bacillus mycoides. The optimal conditions for enzyme production were pH 9'0, 3% (wlv) dextrin as carbon source, (NH4hS04 (0'1%, wlv) and peptone (0-1%, wlv) as nitrogen sources and KH Z P0 4 at 1·0 gil. The enzyme was immobilized on various carriers by different methods of...

The electrical characterization of metal contacts to Cl and N-doped ZnSe material systems is reported. Metalorganic vapor phase epitaxy (MOVPE) was used to grow the doped ZnSe samples at 330°C. With intentional chlorine doping using 1-chlorobutane, free electron concentrations of up to 8×10¹⁷ cm^-3 have been achieved. Photolumi...

Bacillus subtilis 1 a-amylase was immobilized on different carriers by different methods of immobilization. The immo bilized enzymes were prepared by physical adsorption on aminoalkylsilane-alumina (AS-alumina), ionic binding onto DEAE-cellulose. covalent binding on chitin, and entrapment in polyacrylamide had the highest activities. The specific a...

The production of cellobiase was investigated using a submerged culture of Aspergillus niger A20. The maximum production occurred when the pH was controlled and maintained at 4.0 during the fermentation process. Lactose (0.2%, w/v) and cellulose (1.5%, w/v) were the most favourable carbon sources. Yeast extract (0.05%, w/v) peptone (0.025%, w/v), u...

P‐doped Mg x Zn 1-x Te alloys (0≤x≤0.28) are characterized using room‐temperature electrical, optical, and photoelectric measurements. The electrical properties (hole concentration and mobility) indicate an increasing compensation with the increase of Mg content. The donor impurities are attributed to P. The optical absorption spectrum exhibits a p...

Production of a cellobiase-rich preparation by Aspergillus niger 1 was achieved using water hyacinth cellulose as the sole carbon source in the culture medium. Production of cellobiase, carboxymethylcellulase (CMC-ase) and filter paper (FP)-cellulase was favoured by controlling the pH of the culture medium during fermentation at 5.0. Sodium citrate...

Laser heating of a two-layer system is studied and the temperature dependence of the optical absorptance of the irradiated target is considered. The Laplace integral method is used to solve the heating problem. Expressions for the temperature profiles in the thin film and the substrate are obtained. Such profiles, together with the surface temperat...

Aspergillus niger NRC 107 xylanase and β-xylosidase were immobilized on various carriers by different methods of immobilization, including physical adsorption, covalant binding, ionic binding, and entrapment. The immobilized enzymes were prepared by physical adsorption on tannin-chitosan, ionic binding onto Dowex-50W, covalent binding on chitosan b...