Ibrahim, Abdelnasser S. S.Abdelnasser S. S.IbrahimAl-Salamah, Ali A.Ali A.Al-SalamahEl-Tayeb, Mohamed A.Mohamed A.El-TayebElbadawi, Yahya B.Yahya B.ElbadawiAntranikian, GarabedGarabedAntranikian2017-08-292017-08-292012-08-22International Journal of Molecular Sciences 13 (2012), 8, S. 10505-10522http://tubdok.tub.tuhh.de/handle/11420/1423Screening 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<strong> </strong>identified the isolate as <em>Amphibacillus</em><em> </em>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. <em>K</em>_m and <em>V</em>_max 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 <em>Amphibacillus</em> sp. The achieved high conversion of insoluble raw corn starch into cyclodextrins (67.2%) with production of mainly β-CD (86.4%), makes <em>Amphibacillus</em> sp. NPST-10 desirable for the cyclodextrin production industry.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<strong> </strong>identified the isolate as <em>Amphibacillus</em><em> </em>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. <em>K</em>_m and <em>V</em>_max 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 <em>Amphibacillus</em> sp. The achieved high conversion of insoluble raw corn starch into cyclodextrins (67.2%) with production of mainly β-CD (86.4%), makes <em>Amphibacillus</em> sp. NPST-10 desirable for the cyclodextrin production industry.en1422-00672012Multidisciplinary Digital Publishing Institutehttps://creativecommons.org/licenses/by/3.0/Biowissenschaften, BiologieJournal Article2017-08-24urn:nbn:de:gbv:830-882w0216610.15480/882.142011420/142310.3390/ijms13081050510.15480/882.1420Other