Jabbour, DinarDinarJabbourSorger, AnnekeAnnekeSorgerSahm, KerstinKerstinSahmAntranikian, GarabedGarabedAntranikian2019-09-052019-09-052013Applied Microbiology and Biotechnology 7 (97): 2971-2978 (2013)http://hdl.handle.net/11420/3301Aiming at the isolation of novel enzymes from previously uncultured thermophilic microorganisms, a metagenome library was constructed from DNA isolated from a pilot-plant biogas reactor operating at 55 °C. The library was screened for starch-degrading enzymes, and one active clone was found. An open reading frame of 1,461 bp encoding an α-amylase from an uncultured organism was identified. The amy13A gene was cloned in Escherichia coli, resulting in high-level expression of the recombinant amylase. The novel enzyme Amy13A showed the highest sequence identity (75 %) to α-amylases from Petrotoga mobilis and Halothermothrix orenii. Amy13A is highly thermoactive, exhibiting optimal activity at 80 °C, and it is also highly salt-tolerant, being active in 25 % (w/v) NaCl. Amy13A is one of the few enzymes that tolerate high concentrations of salt and elevated temperatures, making it a potential candidate for starch processing under extreme conditions. © 2012 The Author(s).en1432-06142013729712978Springerα-AmylaseCalcium-dependentGlycoside hydrolase family 13HalophileMetagenomePetrotogaThermophileNaturwissenschaftenBiowissenschaften, BiologieJournal Article10.1007/s00253-012-4194-xOther