title: A novel raw starch digesting alpha-amylase from a newly isolated Bacillus sp. YX-1: purification and characterization.
abstract: This study reports the purification and characterization of a novel raw starch digesting alpha-amylase from a newly isolated Bacillus sp. YX-1. Maximum alpha-amylase activity (53 U mL(-1)) was obtained at 45 degrees C after 44 h of incubation. The enzyme was purified using ammonium sulfate precipitation, ion exchange and gel filtration chromatography, and showed a molecular weight of 56 kDa by SDS-PAGE. This enzyme exhibited maximum activity at pH 5.0, performed stability over a broad range of pH 4.5-11.0, and was optimally active at 40-50 degrees C. The enzyme preparation had a strong digesting ability towards various raw starches and efficiently hydrolyzed raw corn starch at a concentration of 20% and pH 5.0, which were normally used in the starch industries, in a period of 12h. By analyzing its partial amino acid sequences, the enzyme was proposed to be a novel alpha-amylase.
authors.affiliation: Key Laboratory of Industrial Biotechnology of Ministry of Education and School of Biotechnology, Southern Yangtze University, Wuxi 214036, PR China.
authors.forename: Xu Dong
authors.initials: XD
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
mesh_terms: D000645:Ammonium Sulfate / Q000032:analysis; D001407:Bacillus / Q000201:enzymology* / Q000378:metabolism; D001709:Biotechnology / Q000379:methods*; D002845:Chromatography / Q000379:methods; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange / Q000379:methods; D004275:DNA, Ribosomal / Q000737:chemistry; D003911:Dextrans / Q000737:chemistry; D004983:Ethanolamines / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D012685:Sepharose / Q000032:analysis; D013696:Temperature; D013997:Time Factors; D000516:alpha-Amylases / Q000737:chemistry* / Q000302:isolation & purification*
chemical_list: D004275:DNA, Ribosomal; D003911:Dextrans; D004983:Ethanolamines; D012685:Sepharose; C025614:sephadex; D000516:alpha-Amylases; C007369:2-diethylaminoethanol; D000645:Ammonium Sulfate