A novel thermostable, acidophilic alpha-amylase from a new thermophilic "Bacillus sp. Ferdowsicous" isolated from Ferdows hot mineral spring in Iran: Purification and biochemical characterization.

This paper describes the purification and characterization of a novel acidophile alpha-amylase from newly isolated Bacillus sp. Ferdowsicous. The enzyme displayed a molecular weight of 53 kDa and it was stable over a range of pH from 3.5 to 7 with an optimum around 4.5. The optimum temperature for activity was found to be around 70 degrees C and the enzyme remained active to more than 75% up to 75 degrees C for 45 min. The enzyme activity was decreased by Zn(2+)and EDTA but inhibited by Hg(2+), whereas the activity was increased by approximately 15% by Ba(2+) and Fe(2+). Na(+), Mg(2+), K(+), Ca(2+), PMSF, Triton X-100 and beta-mercaptoethanol had any considerable effect on its activity. The enzyme activity on the amylose as substrate was 1.98 times greater than amylopectin. Partial N-terminal sequencing demonstrated no significant similarity with other known alpha-amylases, indicating that the presented enzyme was new. Considering its promising properties, this enzyme can find potential applications in the food industry as well as in laundry detergents.