Production of a novel α-amylase by Bacillus atrophaeus NRC1 isolated from honey: Purification and characterization.

Autor: Abd-Elaziz AM; Molecular Biology Department, National Research Center, 33-El Bohouthst., Dokki P.O.12622, Gieza, Egypt. Electronic address: ahmedmoselhy2000@yahoo.com., Karam EA; Microbial Chemistry Department, National Research Center, 33-El Bohouthst., Dokki P.O.12622, Giza, Egypt., Ghanem MM; Molecular Biology Department, National Research Center, 33-El Bohouthst., Dokki P.O.12622, Gieza, Egypt., Moharam ME; Microbial Chemistry Department, National Research Center, 33-El Bohouthst., Dokki P.O.12622, Giza, Egypt., Kansoh AL; Microbial Chemistry Department, National Research Center, 33-El Bohouthst., Dokki P.O.12622, Giza, Egypt.
Jazyk: angličtina
Zdroj: International journal of biological macromolecules [Int J Biol Macromol] 2020 Apr 01; Vol. 148, pp. 292-301. Date of Electronic Publication: 2020 Jan 13.
DOI: 10.1016/j.ijbiomac.2020.01.120
Abstrakt: Different bacterial isolates with amylolytic activity were insulated from various honey samples. The most active isolate was identified by the molecular 16SrRNA sequence technique as Bacillus atrophaeus NRC1. The bacterium showed maximum amylase production under optimum culture conditions at pH 6.0, 40 °C and after 24 h incubation. Two amylase isoenzymes (AmyI and AmyII) from Bacillus atrophaeus NRC1 have been purified to homogeneity by using ammonium sulfate precipitation, Sephacryl S-200 and DEAE-Sepharose chromatography. The major isoenzyme, AmyI, had a specific activity 4635 U/mg proteins with molecular weight of 61 kDa using SDS-PAGE electrophoresis. The maximum activity of AmyI against starch was determined at pH 6.0 and 50 °C. AmyI was stable up to 50 °C after incubation for 30 min, retained 65 and 23% of its activity at 60 and 70 °C, respectively. Pre-incubation with Ca 2+ , Mg 2+ and Ba 2+ cations for 30 min enhanced the enzyme activity; while it was completely inhibited by Hg 2+ . Varied inhibition degree of the enzyme activity was determined with K + , Ni 2+ , Zn 2+ , Na 2+ and Cu 2+ ions. AmyI was inhibited by EDTA, PMSF and SDS, while it was activated by l-Cysteine-HCl and DTT. AmyI had the ability to degrade starch, amylopectin, glycogen, amylose and lacked the affinity towards β-1,4-linked xyloses.
(Copyright © 2020 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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