title: Isolation and characterisation of a novel alpha-amylase from the extreme haloarchaeon Haloterrigena turkmenica.
abstract: An extracellular halophilic alpha-amylase (AmyA) was produced by the haloarchaeon Haloterrigena turkmenica grown in medium enriched with 0.2% (w/v) starch. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography (SEC) analyses showed a major band at 66.0kDa and a peak of 54.0kDa, respectively. Analysis of tryptic fragments of the protein present in the major SDS-PAGE band by nano-LC-ESI-MS/MS led to identification of the alpha-amylase catalytic region, encoded by the htur2110 gene, as the protein possessing the described activity. Optimal values for activity were 55°C, pH 8.5 and 2M NaCl, and high thermostability was showed at 55°C and 3M NaCl. AmyA activity was enhanced by Triton X-100 and was not influenced by n-hexane and chloroform. Starch hydrolysis produced different oligomers with maltose as the smallest end-product. The efficiency of AmyA in degrading starch contained in agronomic residues was tested in grape cane chosen as model substrate. Preliminary results showed that starch was degraded making the enzyme a potential candidate for utilization of agro-industrial waste in fuel and chemicals production. AmyA is one of the few investigated amylases produced by haloarchaea, and the first alpha-amylase described among microorganisms belonging to the genus Haloterrigena.
authors.affiliation: Department of Chemical, Materials and Production Engineering, University of Naples "Federico II", P.le Tecchio 80, 80125 Napoli, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Santorelli
authors.affiliation: Institute of Biosciences and Bioresources, National Research Council of Italy, Via Pietro Castellino 111, 80131 Naples, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Maurelli
authors.affiliation: Institute of Biosciences and Bioresources, National Research Council of Italy, Via Pietro Castellino 111, 80131 Naples, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Pocsfalvi
authors.affiliation: Institute of Biosciences and Bioresources, National Research Council of Italy, Via Pietro Castellino 111, 80131 Naples, Italy.
authors.forename: Immacolata
authors.initials: I
authors.lastname: Fiume
authors.affiliation: Institute of Agro-environmental and Forest Biology, National Research Council of Italy, Via Pietro Castellino 111, 80131 Naples, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Squillaci
authors.affiliation: Institute of Agro-environmental and Forest Biology, National Research Council of Italy, Via Pietro Castellino 111, 80131 Naples, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: La Cara
authors.affiliation: Institute of Biosciences and Bioresources, National Research Council of Italy, Via Pietro Castellino 111, 80131 Naples, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Del Monaco
authors.affiliation: Institute of Agro-environmental and Forest Biology, National Research Council of Italy, Via Pietro Castellino 111, 80131 Naples, Italy. Electronic address: alessandra.morana@ibaf.cnr.it.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Morana
mesh_terms: D000595:Amino Acid Sequence; D001105:Archaea / Q000201:enzymology* / Q000254:growth & development; D002118:Calcium / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D004492:Edetic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007477:Ions; D009930:Organic Chemicals / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D012997:Solvents; D013213:Starch / Q000378:metabolism; D013379:Substrate Specificity / Q000187:drug effects; D013501:Surface-Active Agents / Q000494:pharmacology; D013696:Temperature; D000516:alpha-Amylases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D007477:Ions; D009930:Organic Chemicals; D012997:Solvents; D013501:Surface-Active Agents; D012965:Sodium Chloride; D013213:Starch; D004492:Edetic Acid; D000516:alpha-Amylases; D002118:Calcium
keywords: Alpha-amylase; Archaeon; Halophile; Haloterrigena turkmenica