Document Type: Research article
Department of Biotechnology, University of Karachi, Karachi-75270, Pakistan.
Phytochemistry Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Department of Pharmacognosy, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Department of Chemistry, University of Karachi, Karachi-75270, Pakistan
Department of Pharmaceutical Chemistry, University of Karachi, Karachi-75270, Pakistan.
Bacillus licheniformis RM44 was isolated from hot spring near Karachi and screened for
the production of extracellular amylase Amy RM44. Amy RM44 was purified to homogeneity
on a single step by affinity chromatography using insoluble corn starch. The molecular weight
of Amy RM44 was estimated to be 66 kDa by SDS–PAGE and zymographic analysis. Nine fold
purification was achieved with the specific activity of 870 U/mg that provides the total yield
of the enzyme up to 31%. Studies on purified AmyRM44 characterization revealed that the
optimum temperature of enzyme was 100 ºC. Amy RM44 was proved to be highly thermostable
as it retained 50% activity after 2 h at 100 ºC. Amy RM44 was stable over wide range of pH
with optimum activity at pH 5. Enzyme activity was not significantly inhibited by SDS and
EDTA. Amy RM44 also exhibited its activity towards various carbohydrates such as dextrin,
pullulan, α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin.