Purification and characterization of an organic-solvent-tolerant halophilic α-amylase from the moderately halophilic Nesterenkonia sp. strain F

Abstract

A halophilic α-amylase produced by Nesterenkonia sp. strain F was purified to homogeneity by 80% ethanol precipitation, Q-Sepharose anion exchange, and Sephacryl S-200 gel filtration chromatography. The purified amylase exhibited specific activity of 357 unit/mg protein that corresponds to twofold purification. The molecular mass of the amylase was determined to be 57 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography. The optimal pH and temperature for enzyme activity were 6.5 and 45°C, respectively. The amylase was active over a wide range of salt concentrations (0-4 M) with maximum activity at 0.75-1 M NaCl. The α-amylase activity was stimulated by Ca(2+) and inhibited by ethylenediamine tetraacetic acid (EDTA), suggesting that this enzyme is a metalloenzyme. The purified enzyme showed remarkable stability towards surfactants (Tween 20, Tween 80, and Triton X-100), and its activity was increased by β-mercaptoethanol. The halophilic α-amylase was stable in the presence of various organic solvents such as benzene, chloroform, toluene, and cyclohexane. These properties indicate wide potential applications of this α-amylase in starch-processing industries.

Strain improvement studies on <i>Microbacterium foliorum</i> GA2 for production of α-amylase in solid state fermentation: Biochemical characteristics and wash performance analysis at low temperatures

“…The chelating agent EDTA inhibited enzyme activity, indicating that the enzyme has a divalent ion required for its structural integrity. A similar result was also observed by Shafiei et al (2011), Zhang and Zeng (2008) and Sindhu et al Fig. 3.…”

Production and Characterization of α-Amylase from an Extremely Halophilic Archaeon, Haloferax sp. HA10

“…Recently, an extracellular halophilic α-amylase from Nesterenkonia sp. strain F has shown maximum activity at 0.5 M NaCl and was active up to 4 M salt concentration (26). In contrast, amylase from Halobacillus sp.…”

Halophilic Properties and their Manipulation and Application

“…They were more stable in nonmiscible than in water-miscible organic solvents (Shafiei et al, 2011). This is reminiscent of dried enzymes in organic solvents (Zaks and Klibanov, 1984, 1985Volkin et al, 1991;Vermue and Tramper, 1995).…”