Mohammad Reza Rokhforouz - Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran
Reza Roostaazad - Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran

α-amylase is an important industrial bulk enzyme which has wide range of applications in the industrial front such as fermentation, pharmaceutical, and food. α-amylase is produced by animal, plant, and microbial sources; however, the industrial sectors mostly rely on the microbial amylase. In this paper, α-amylase from a culture supernatant of Bacillus subtilis is partially purified using polyethylene glycol /phosphate aqueous two-phase system. Furthermore, the effects of two independent factor including polyethylene glycol molecular weight, and salt type on the partition coefficient, and purification factor (PF) were studied. The obtained results revealed that the most concentrated purified crude extracts (PF=3.97, and partition coefficient=1.32) were achieved at 25◦C and pH 6 using 18% (w/w) PEG 6000 g/mol, 8% (w/w) phosphate buffer, and 3%(w/w) KCl. It can be concluded that optimization of enzyme extraction is crucial to improve enzyme characteristics and also reduce downstream processing’ costs.

α-amylase, Bacillus subtilis, Aqueous two-phase system (ATPS), Partial Purification