title: Cloning and expression of acidstable, high maltose-forming, Ca2+-independent α-amylase from an acidophile Bacillus acidicola and its applicability in starch hydrolysis.
abstract: The α-amylase encoding gene from acidophilic bacterium Bacillus acidicola was cloned into pET28a(+) vector and expressed in Escherichia coli BL21 (DE3). The recombinant E. coli produced a 15-fold higher α-amylase than B. acidicola strain. The recombinant α-amylase was purified to homogeneity by one-step nickel affinity chromatography using Ni(2+)-NTA resin with molecular mass of 62 KDa. It is active in the pH range between 3.0 and 7.0 and 30 and 100 °C with optimum at pH 4.0 and 60 °C. The enzyme is Ca(2+)-independent with K                         (m) and k                         (cat) values (on soluble starch) of 1.6 mg ml(-1) and 108.7 s(-1), respectively. The α-amylase of B. acidicola is acidstable, high maltose forming and Ca(2+)-independent, and therefore, is a suitable candidate for starch hydrolysis and baking.
authors.affiliation: Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
authors.forename: Archana
authors.initials: A
authors.lastname: Sharma
authors.forename: T
authors.initials: T
authors.lastname: Satyanarayana
mesh_terms: D001407:Bacillus / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D002118:Calcium / Q000737:chemistry*; D003001:Cloning, Molecular; D004795:Enzyme Stability / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D013213:Starch / Q000737:chemistry*; D000516:alpha-Amylases / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D013213:Starch; D000516:alpha-Amylases; D002118:Calcium