Purification of soybean amylase by superparamagnetic particles

Many studies of purification technology have focused on the development of supports of substrates for isolating enzymes. In this study, superparamagnetic particles modified by epichlorohydrin and other cross-linking agents to coat with starch were used as a purification support for isolating amylases from soybean proteins after precipitation with ammonium sulphate. The recovery of amylase activity from the crude amylase was 17.50% with a 194-fold purification. The molecular weight of the purified amylase was estimated to be 70 kDa by SDS–PAGE. Both crude and purified amylases showed an optimum pH of 6.0 with optimum temperatures of 70 and 60–70 °C and thermal stability of 20–70 and 20–60 °C, respectively. Since the affinity magnetic carrier could adsorb the target proteins efficiently, the superparamagnetic particles technology can be further combined with other separation technologies in the industries to enhance their purification efficiency.