title: Purification and Characterization of a Polyextremophilic α -Amylase from an Obligate Halophilic Aspergillus penicillioides Isolate and Its Potential for Souse with Detergents.
abstract: An extracellular α-amylase from the obligate halophilic Aspergillus penicillioides TISTR3639 strain was produced and enriched to apparent homogeneity by ammonium sulfate precipitation and Sephadex G100 gel filtration column chromatography. The mass of the purified amylase was estimated to be 42 kDa by SDS-PAGE. With soluble starch as the substrate it had a specific activity of 118.42 U · mg(-1) and Vmax and Km values of 1.05 µmol · min(-1) · mg(-1) and 5.41 mg · mL(-1), respectively. The enzyme was found to have certain polyextremophilic characteristics, with an optimum activity at pH 9, 80 °C, and 300 g · L(-1) NaCl. The addition of CaCl2 at 2 mM was found to slightly enhance the amylase activity, while ZnCl2, FeCl2, or EDTA at 2 mM was strongly or moderately inhibitory, respectively, suggesting the requirement for a (non-Fe(2+) or Zn(2+)) divalent cation. The enzyme retained more than 80% of its activity when incubated with three different laundry detergents and had a better performance compared to a commercial amylase and three detergents in the presence of increasing NaCl concentrations up to 300 g · L(-1). Accordingly, it has a good potential for use as an α-amylase in a low water activity (high salt concentration) and at high pH and temperatures.
authors.affiliation: Plant Biomass Utilization Research Unit, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand ; Institute of Biochemistry, University of Balochistan, Quetta 87300, Pakistan.
authors.forename: Imran
authors.initials: I
authors.lastname: Ali
authors.affiliation: Department of Microbiology, University of Balochistan, Quetta 87300, Pakistan.
authors.forename: Ali
authors.initials: A
authors.lastname: Akbar
authors.affiliation: Institute of Biochemistry, University of Balochistan, Quetta 87300, Pakistan.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Anwar
authors.affiliation: Plant Biomass Utilization Research Unit, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Sehanat
authors.initials: S
authors.lastname: Prasongsuk
authors.affiliation: Plant Biomass Utilization Research Unit, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Pongtharin
authors.initials: P
authors.lastname: Lotrakul
authors.affiliation: Plant Biomass Utilization Research Unit, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Hunsa
authors.initials: H
authors.lastname: Punnapayak
mesh_terms: D001230:Aspergillus / Q000201:enzymology*; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D000516:alpha-Amylases / Q000737:chemistry* / Q000302:isolation & purification*
chemical_list: D005656:Fungal Proteins; D000516:alpha-Amylases