23] Entrapment of microbial cells in cellulose gel

Abstract

This chapter discusses a novel, efficient, mild, and simple method for the entrapment of enzyme-active microbial cells in cellulose gel fibers and beads. If microbial cells are to be entrapped in a cellulose gel, cellulose has to be first dissolved in a suitable solvent and subsequently regenerated as a gel. The dissolution of cellulose is, however, a difficult task. Typically strong reagents have to be used, making the process impractical for bioactive materials. Cellulose gel in bead form has been prepared from cellulose solutions obtained by the viscose and cuprammonium processes and by the hydrolysis of cellulose derivatives after bead formation. The chemical reagents required in the first two methods are far too severe for the entrapment of biologically active microbial cells. Only cellulose derivatives, such as di- and tri-acetate, nitrate, and diethylaminoethyl (DEAE)-cellulose have been employed previously with success both in fiber and in membrane forms or as adsorbents for the immobilization of whole microbial cells. Cellulose beads prepared through acetate have also been employed for immobilization after the activation of the obtained bead cellulose.