Psychrophilic α-amylase from Aeromonas veronii NS07 isolated from farm soils |
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Authors: | Nima Samie Kambiz Akbari Noghabi Zahra Gharegozloo Hossien Shahbani Zahiri Gholamreza Ahmadian Hakimeh Sharafi Reza Behrozi Hojatollah Vali |
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Institution: | 1. Department of Molecular Genetics, National Institute of Genetic Engineering and Biotechnology (NIGEB), P.O. Box 14155-6343, Tehran, Iran;2. Facility for Electron Microscopy Research, McGill University, 3640 Street, Montreal, Quebec, Canada H3A 2B2 |
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Abstract: | Among 120 isolates examined in this study, three isolates were selected for amylase production on starch agar plates following incubation at 10 °C. Identification by 16SrRNA on selected bacterium disclosed the highest similarity for protean regions of this gene as Aeromonas veronii NS07. A 63 kDa psychrophilic amylase enzyme from NS07 strain was purified by two-steps chromatography. The enzyme had the highest specific activity at pH 4 and was active at the range of temperatures from 0 to 50 °C, although the optimum temperature for enzyme activity was found at 10 °C. Analysis of the N-terminal amino acid sequencing disclosed 20 amino acids from purified amylase which had no similarity with other known α-amylases, indicating that the presented enzyme was novel. Amylase activity was enhanced in relation to optimum activity with the presence of sodium sulphate (161%), MnCl2 (298%), CaCl2 (175%), FeCl2 (182%), MgCl2 (237%), ZnCl2 (169%), NiCl2 (139%), NaCl (158%), each at 5 mM, while EDTA, phenylmethane sulphonylfluoride (PMSF) (3 mM), urea (8 M) and SDS (1%) inhibited the enzyme up to 5%, 2%, 80% and 18%, respectively. NS07 strain seems to be suitable as biocatalyst for practical use in liquefaction of starch at low temperatures, detergent and textile industries. |
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