ALGINATE-STARCH COPOLYMERS AND IMMOBILIZED STARCH AS AFFINITY ADSORBENTS FOR ALPHA-AMYLASE

Novel adsorbents for the isolation of alpha-amylase are described. The first adsorbent is a co-polymer of alginate and starch. Water-soluble starch was converted into a bead form by CaCl2 complexation of an alg inate/starch mixture. The starch was made insoluble by a cross-linking reaction with epichlorohydrin. Another type of adsorbent is obtained by immobilization of cross-linked starch in an alginate matrix. The pr eparation of the adsorbents was optimized with respect to adsorption c apacity and enzymic breakdown by alpha-amylase. The two adsorbents pro ved to be useful in the purification of amylases from diverse sources. With respect to the equilibrium conditions they have comparable prope rties. Mass transfer is more restricted in the first adsorbent, probab ly due to increased diffusion resistance in the co-polymer matrix. In addition, these adsorbents may be useful for the direct recovery of th e enzyme from unclarified fermentation media or cell homogenates.