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Publisher DOI: 10.3390/ijms130810505
Title: A novel cyclodextrin glycosyltransferase from alkaliphilic amphibacillus sp. NPST-10 : purification and properties
Language: English
Authors: Ibrahim, Abdelnasser S. S. 
Al-Salamah, Ali A. 
El-Tayeb, Mohamed A. 
Elbadawi, Yahya B. 
Antranikian, Garabed 
Issue Date: 22-Aug-2012
Publisher: Multidisciplinary Digital Publishing Institute
Source: International Journal of Molecular Sciences 13 (2012), 8, S. 10505-10522
Journal or Series Name: International journal of molecular sciences 
Abstract (english): Screening for cyclodextrin glycosyltransferase (CGTase)-producing alkaliphilic bacteria from samples collected from hyper saline soda lakes (Wadi Natrun Valley, Egypt), resulted in isolation of potent CGTase producing alkaliphilic bacterium, termed NPST-10. 16S rDNA sequence analysis identified the isolate as Amphibacillus sp. CGTase was purified to homogeneity up to 22.1 fold by starch adsorption and anion exchange chromatography with a yield of 44.7%. The purified enzyme was a monomeric protein with an estimated molecular weight of 92 kDa using SDS-PAGE. Catalytic activities of the enzyme were found to be 88.8 U mg−1 protein, 20.0 U mg−1 protein and 11.0 U mg−1 protein for cyclization, coupling and hydrolytic activities, respectively. The enzyme was stable over a wide pH range from pH 5.0 to 11.0, with a maximal activity at pH 8.0. CGTase exhibited activity over a wide temperature range from 45 °C to 70 °C, with maximal activity at 50 °C and was stable at 30 °C to 55 °C for at least 1 h. Thermal stability of the purified enzyme could be significantly improved in the presence of CaCl2. Km and Vmax values were estimated using soluble starch as a substrate to be 1.7 ± 0.15 mg/mL and 100 ± 2.0 μmol/min, respectively. CGTase was significantly inhibited in the presence of Co2+, Zn2+, Cu2+, Hg2+, Ba2+, Cd2+, and 2-mercaptoethanol. To the best of our knowledge, this is the first report of CGTase production by Amphibacillus sp. The achieved high conversion of insoluble raw corn starch into cyclodextrins (67.2%) with production of mainly β-CD (86.4%), makes Amphibacillus sp. NPST-10 desirable for the cyclodextrin production industry.
DOI: 10.15480/882.1420
ISSN: 1422-0067
Other Identifiers: doi: 10.3390/ijms130810505
Institute: Technische Mikrobiologie V-7 
Type: (wissenschaftlicher) Artikel
License: CC BY 3.0 (Attribution) CC BY 3.0 (Attribution)
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