Novel enzyme-membrane reactor for polysaccharide synthesis

The synthesis of a polysaccharide from the substrate sucrose was carried ou t with help of a novel enzyme-membrane reactor. Commercially available capi llary pore membranes with diameters of 0.4, 1.0 and 3.0 mu m had to be modi fied for covalent enzyme immobilization within the pores. This was achieved by heterogeneous photoinitiated graft copolymerization. A grafted poly-(2- amino ethyl methacrylate) layer with glutardialdehyde activation was partic ularly suited for coupling of fructosyltransferase (FTF, inulinsucrase from Streptococcus mutans), yielding enzyme-membranes with high permeabilities and essentially unchanged FTF activities. However, for a continuous enzymat ic reaction driven by trans-membrane substrate flow, it was necessary to us e membranes with rather spacious cylindrical pores (3.0 mu m) to avoid thei r blocking by the produced polyfructan (inulin). The synthesized inulins ha d a molecular weight between 30 and 50 Mio g/mol with a very low polydisper sity. (C) 1999 Elsevier Science B.V. All rights reserved.