title: Gene cloning and characterization of a thermostable organic-tolerant α-amylase from Bacillus subtilis DR8806.
abstract: The gene encoding an extracellular α-amylase from Bacillus subtilis DR8806 was cloned into pET28a(+) vector and expressed in Escherichia coli BL21 (DE3). The recombinant enzyme with molecular mass of 76 kDa exhibited optimal activity at pH 5.0 and 70 °C with high stability in pH and temperature ranges of 4.0-9.0 and 45-75 °C. The enzyme showed a half-life of 125 min at 70 °C. The α-amylase activity enhanced in the presence of Na(+), K(+), and Ca(2+) ions, while Zn(2+), Pb(2+), and Hg(2+) ions inhibited the activity. The recombinant α-amylase exhibited high stability towards ioninc detergents sodium dodecyl sulfate (SDS) and cetyl trimethylammonium bromide (CTAB). Organic solvents in reaction media increased the α-amylase activity. TLC analysis showed that maltoriose and maltose were the major end products of enzymatic starch hydrolysis. Presenting various properties of recombinant α-amylase makes it well suited as a potential candidate for industrial usages.
authors.affiliation: Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Vakil-Abad Blv., Mashhad, Razavi Khorasan 9177948974, Iran.
authors.forename: Shamsi
authors.initials: S
authors.lastname: Emtenani
authors.affiliation: Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Vakil-Abad Blv., Mashhad, Razavi Khorasan 9177948974, Iran; Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran. Electronic address: asoodeh@um.ac.ir.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Asoodeh
authors.affiliation: Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Vakil-Abad Blv., Mashhad, Razavi Khorasan 9177948974, Iran.
authors.forename: Shirin
authors.initials: S
authors.lastname: Emtenani
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology*; D003001:Cloning, Molecular; D004795:Enzyme Stability; D004926:Escherichia coli; D015964:Gene Expression Regulation, Bacterial; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013213:Starch / Q000737:chemistry; D013696:Temperature; D000516:alpha-Amylases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D012967:Sodium Dodecyl Sulfate; D013213:Starch; D000516:alpha-Amylases
keywords: Bacillus subtilis DR8806; Cloning; Maltotriose, Thermotolerant; Organic solvent; α-Amylase