Gum Tragacanth Gels as a New Supporting Matrix for Immobalization of Whole-Cell

We introduce a new smooth, non-toxic, biocompatible method for cross-linking ofgum tragacanth (gt), a polysaccharide of natural origin, in order to serve as a new supportingmatrix for immobilization systems. the modified gum is used as a matrix for the catalysis oftheconversion of benzyl penicillin to 6-aminopenicillanic acid (6-apa) by means of escherichia coliatcc11105 with penicillin g acylase (pga) activity. the results show that gt beads can not onlyserve as a proper matrix for immobilization, but show enhanced hydrolysis rate and stabilitycompared to other immobilization systems usedfor this reaction. this signifies the potential ofgtas a biocompatible matrix for immobilization and its positive prospects for use in more demandingimmobilization applications where traditional matrices such as alginate may fall short. the effect ofenvironmental factors, such as temperature, ph, and substrate concentration, have also beenstudied on the hydrolysis rate and compared with the other immobilizing systems usedfor the samereaction, such as calcium alginate. under the optimal conditions, penicillin g conversion reached91.5% after 6 h and remained over 80% after 45 repeated cycles of6 h each.