Consulta: creatorFacets:"El-Tayeb,Mohamed A"
Registros recuperados: 5
Data/hora: 05/06/2024 07:57:59

Isolation and characterization of novel potent Cr(VI) reducing alkaliphilic Amphibacillus sp. KSUCr3 from hypersaline soda lakes
Provedor de dados: 69
Autores: Ibrahim,Abdelnasser S.S; El-Tayeb,Mohamed A; Elbadawi,Yahya B; Al-Salamah,Ali A.
A strain KSUCr3 with extremely high Cr(VI)-reducing ability under alkaline conditions was isolated from hypersaline soda lakes and identified as Amphibacillus sp. on the basis of 16S rRNA gene sequence analysis. The results showed that Amphibacillus sp. strain KSUCr3 was tolerance to very high Cr(VI) concentration (75 mM) in addition to high tolerance to other heavy metals including Ni2+ (100 mM), Mo2+ (75 mM), Co2+ (5 mM), Mn2+ (100 mM), Zn2+ (2 mM), Cu2+ (2 mM) and Pb (75 mM). Strain KSUCr3 was shown to be of a high efficiency in detoxifying chromate, as it could rapidly reduce 5 mM of Cr(VI) to a non detectable level over 24 hrs. In addition, strain KSUCr3 could reduce Cr(VI) efficiently over a wide range of initial Cr(VI) concentrations (1-10 mM) in...
Tipo: Journal article
Palavras-chave: Amphibacillus sp.; Bioremediation; Chromate reduction; Heavy metals; Soda lake.
Ano: 2011
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582011000400004

Cyclodextrin glucanotransferase immobilization onto functionalized magnetic double mesoporous core-shell silica nanospheres
Provedor de dados: 69
Autores: Ibrahim,Abdelnasser S.S.; Al-Salamah,Ali A; El-Toni,Ahmed Mohamed; El-Tayeb,Mohamed A; Elbadawi,Yahya B.
Background Cyclodextrin glucanotransferase (CGTase) from Amphibacillus sp. NPST-10 was covalently immobilized onto amino-functionalized magnetic double mesoporous core-shell silica nanospheres (mag@d-SiO2@m-SiO2-NH2), and the properties of the immobilized enzyme were investigated. The synthesis process of the nanospheres included preparing core magnetic magnetite (Fe3O4) nanoparticles, coating the Fe3O4 with a dense silica layer, followed by further coating with functionalized or non-functionalized mesoporous silica shell. The structure of the synthesized nanospheres was characterized using TEM, XRD, and FT-IR analyses. CGTase was immobilized onto the functionalized and non-functionalized nanospheres by covalent attachment and physical adsorption. Results...
Tipo: Journal article
Palavras-chave: Amphibacillus sp; Cyclodextrin glucanotransferase; Cyclodextrins; Double mesoporous core-shell silica nanospheres; Immobilization.
Ano: 2014
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582014000200001

Production of extracellular alkaline protease by new halotolerant alkaliphilic Bacillus sp. NPST-AK15 isolated from hyper saline soda lakes
Provedor de dados: 69
Autores: Ibrahim,Abdelnasser S.S; Al-Salamah,Ali A; Elbadawi,Yahya B; El-Tayeb,Mohamed A; Ibrahim,Shebl Salah Shebl.
Background Alkaline proteases are among the most important classes of industrial hydrolytic enzymes. The industrial demand for alkaline proteases with favorable properties continues to enhance the search for new enzymes. The present study focused on isolation of new alkaline producing alkaliphilic bacteria from hyper saline soda lakes and optimization of the enzyme production. Results A new potent alkaline protease producing halotolerant alkaliphilic isolate NPST-AK15 was isolated from hyper saline soda lakes, which affiliated to Bacillus sp. based on 16S rRNA gene analysis. Organic nitrogen supported enzyme production showing maximum yield using yeast extract, and as a carbon source, fructose gave maximum protease production. NPST-AK15 can grow over a...
Tipo: Journal article
Palavras-chave: Alkaline protease; Alkalophiles; Bacillus sp; Fermentation; Optimization.
Ano: 2015
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582015000300015

Effects of substrates and reaction conditions on production of cyclodextrins using cyclodextrin glucanotransferase from newly isolated Bacillus agaradhaerens KSU-A11
Provedor de dados: 69
Autores: Ibrahim,Abdelnasser S.S; El-Tayeb,Mohamed A; Elbadawi,Yahya B; Al-Salamah,Ali A.
The effects of reaction conditions on cyclodextrins (CDs) production by CGTase from newly isolated Bacillus agaradhaerens KSU-A11 is reported. Among six types of starch tested, potato starch gave highest starch conversion into CDs. In addition, CDs yield was about three fold higher when using gelatinized potato starch in comparison to raw starch. The total CDs production was increased with increasing pH, showing maximum starch conversion at pH 10. Furthermore, the proportion of &amp;#947;-CD was relatively higher under slightly acidic-neutral conditions than at alkaline pH with a maximum proportion of 35.6% at pH 7 compared to 7.6% at pH 10. Maximum starch conversion into CDs was seen at reaction temperature of 55ºC. Lower reaction temperature led to...
Tipo: Journal article
Palavras-chave: Bacillus agaradhaerens; Cyclodextrin glucanotransferase; Cyclodextrinc; Enzymatic reaction; Starch.
Ano: 2011
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582011000500004

Immobilization of cyclodextrin glucanotransferase on aminopropyl-functionalized silica-coated superparamagnetic nanoparticles
Provedor de dados: 69
Autores: Ibrahim,Abdelnasser S.S.; Al-Salamah,Ali A; El-Toni,Ahmed Mohamed; El-Tayeb,Mohamed A; Elbadawi,Yahya B.
Background: Cyclodextrin glycosyltransferase (CGTase) from Amphibacillus sp. NPST-10 was successfully covalently immobilized on aminopropyl-functionalized silica coated superparamagnetic nanoparticles; and the properties of immobilized enzyme were investigated. The synthesis process included preparing of core magnetic magnetite (Fe3O4) nanoparticles using solvothermal synthesis; followed by coating of Fe3O4 nanoparticles with dense amino-functionalized silica (NH2-SiO2) layer using in situ functionalization method. The structure of synthesized Fe3O4@NH2-SiO2 nanoparticles was characterized using TEM, XRD, and FT-IR analysis. Fe3O4@NH2-SiO2 nanoparticles were further activated by gluteraaldehyde as bifunctional cross linker, and the activated nanoparticles...
Tipo: Journal article
Palavras-chave: Amphibacillus sp. NPST-10; Cyclodextrin glucanotransferase; Immobilization; Magnetic nanoparticle; Silica.
Ano: 2013
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582013000600010