Halophilic Amylase Production and Purification from Haloarcula sp. Strain D61

Abstract

The purpose of this study was the production and partial purification of amylase from a halophilic archaeon. The effect of different parameters on enzyme production and its activity was determined. An extracellular halophilic and moderately thermophilic amylase was produced under stress conditions in culture medium containing 23 % salts by a newly isolated haloarchaeal strain, D61. The strain was identified, and the effect of NaCl, pH, temperature, and different nutrition factors on amylase production by the strain was examined. The enzyme was partially purified using gel filtration chromatography and then characterized. According to the biochemical and morphological characterization and analysis of the sequence of 16S rRNA gene, the strain was identified as Haloarcula sp. strain D61. The strain was capable of producing amylase in the presence of NaCl, and the maximum amylase production was at 3-4 M NaCl. Optimum temperature and pH for the enzyme production were detected to be 40-45 °C and 7.0, respectively. Among various carbon sources, maltose induced amylase production, while lactose, sucrose, and glucose repressed the production of the enzyme. MgCl2 was necessary for growth and amylase production by the strain, and no growth and enzyme production was observed in the absence of MgCl2. The optimum activity of the amylase was at pH 6.0, temperatures of 35-40 °C, and 3-5 M NaCl, as the amylase needs NaCl for its activity. Halophilic and moderate thermophilic amylases could be a good option for biotechnological applications or basic studies on enzyme structure to find differences between halophilic and mesophilic enzymes.