FUNGAL CELL IMMOBILIZATION ON ION-EXCHANGE RESINS FOR PULLULAN PRODUCTION

Immobilization of Aureobasidium pullulans strain RP-1 cells by adsorpt ion on the ion exchange resins triethylaminoethyl-cellulose, diethylam inoethyl-cellulose and phosphocellulose, were investigated. Pullulan p roduction by the fungal cells immobilized on triethylaminoethyl-cellul ose was slightly greater than by the cells immobilized on diethylamino ethyl-cellulose or phosphocellulose when the corn syrup-grown cells we re adsorbed at pH 2.0, 6.0 and 7.0. When the cells were adsorbed on th e resins between pH 2.5 and 5.0, similar polysaccharide concentrations were produced by the immobilized cells. The highest polysaccharide le vels were elaborated by strain RP-1 cells immobilized at pH 2.0 on any of the resins tested. Pullulan synthesis ranged from highest to lowes t for cells adsorbed at pH 2.0 on triethylaminoethyl-cellulose, diethy laminoethyl-cellulose and phosphocellulose, respectively, which corres ponded to their level of fungal cell immobilization. At least two 7 da y cycles of pullulan elaboration by cells immobilized on the resins at pH 2.0 was demonstrated, but polysaccharide synthesis diminished for cells immobilized on diethylaminoethyl-cellulose or phosphocellulose d uring the second cycle.