title: Purification and characterization of a novel extracellular halophilic and organic solvent-tolerant amylopullulanase from the haloarchaeon, Halorubrum sp. strain Ha25.
abstract: A halophilic archaeon, Halorubrum sp. strain Ha25, produced extracellular halophilic organic solvent-tolerant amylopullulanase. The maximum enzyme production was at high salt concentration, 3-4 M NaCl. Optimum pH and temperature for enzyme production were 7.0 and 40 °C, respectively. Molecular mass of purified enzyme was estimated to be about 140 kDa by SDS-PAGE. This enzyme was active on pullulan and starch as substrates. The apparent Km for the enzyme activity on pullulan was 4 mg/ml and for soluble starch was 1.8 mg/ml. Optimum temperature for amylolytic and pullulytic activities was 50 °C. Optimum pH for amylolytic activity was 7 and for pullulytic activity was 7.5. This enzyme was active over a wide range of concentrations (0-4.5 M) of NaCl. The effect of organic solvents on the enzyme activities showed that this enzyme was more stable in the presence of non-polar organic solvents than polar solvents. This study is the first report on amylopullulanase production in halophilic bacteria and archaea.
authors.forename: Maryam
authors.initials: M
authors.lastname: Siroosi
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Amoozegar
authors.forename: Khosro
authors.initials: K
authors.lastname: Khajeh
authors.forename: Mostafa
authors.initials: M
authors.lastname: Fazeli
authors.forename: Mehran Habibi
authors.initials: MH
authors.lastname: Rezaei
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000302:isolation & purification; D055352:Halorubrum / Q000201:enzymology*; D006358:Hot Temperature; D009994:Osmolar Concentration; D012997:Solvents
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D012997:Solvents; D006026:Glycoside Hydrolases; C082507:amylopullulanase