Cold-active detergent-stable extracellular α-amylase from Bacillus cereus GA6: Biochemical characteristics and its perspectives in laundry detergent formulation

A psychro-halo-tolerant Bacillus cereus GA6 was isolated from soil of Gangotri glacier, Western Himalaya that produced maximum cold-active α-amylase at 20±1 °C after 96 h of incubation in alkaline medium by using glycerol and ammonium acetate as a substrate. The enzyme was purified to homogeneity (55 kDa) with 53.33% yield and 175.92 U/mg specific activity; and was stable at low temperature (4-37 °C) and in alkaline medium (pH 7-11). The purified enzyme showed maximum activity at 22±1 °C (pH 9) along with Km and Vmax value of 0.27 mg/ml and 2500 U/ml, respectively. The activity was strongly inhibited by Fe2+, Zn2+, H2O2 and CuSO4 while enhanced considerably by Ca2+. The hydrolysates of soluble starch by the enzyme were mainly glucose, maltose and maltotriose. The enzyme showed exceptional resistance ability against chemical denaturants (Urea, SDS and EDTA) and significant compatibility with commercial laundry detergents thus advocating its suitability for detergent formulation.