Purification of α-amylase from thermophilic Bacillus licheniformis SO5 by using a novel method, alternating current magnetic-field assisted three-phase partitioning: Molecular docking and bread quality improvement

A new method, alternating current magnetic field-assisted three-phase partitioning (ACMF-TPP), was performed for α-amylase purification from Bacillus licheniformis SO5. Using conventional three-phase partitioning (TPP), the enzyme achieved 105 % yield and 1.84-fold purity under optimized conditions (30 % (w/v) ammonium sulfate, 1.0:1.5 (v/v), crude extract to t-butanol ratio, pH 9.0, and 30 °C). These conditions were operated under a magnetic field with 70 % kW power and 30 % duty cycle, reducing the contact time from 1 h to 10 min, and 195 % yield and 3.07-fold purity were obtained. The optimum pH, temperature, and molecular weight for the enzyme were 7.0 and 50 °C, ∼68.7 kDa, respectively. α-Amylase showed high activity across a wide temperature range and with various substances. Molecular docking revealed that maltotriose and wheat starch showed the highest binding affinity. Bread baking tests were conducted to investigate the use of purified α-amylase in the food industry, demonstrating that the enzyme enhances bread quality.