NOVEL METHOD FOR POLYSACCHARIDE SYNTHESIS USING AN ENZYME - THE 1ST INVITRO SYNTHESIS OF CELLULOSE VIA A NONBIOSYNTHETIC PATH UTILIZING CELLULASE AS CATALYST

The in vitro synthesis of cellulose via a nonbiosynthetic path has been achieved for the first time by condensation of beta-D-cellobiosyl fluoride as substrate for cellulase, a hydrolysis enzyme of cellulose, in a mixed solvent of acetonitrile/acetate buffer (pH 5, 5:1). The water-insoluble part of the products is ''synthetic cellulose'', the structure of which was confirmed by comparison with an authentic natural cellulose sample with use of solid C-13 NMR and IR spectroscopies as well as with a hydrolysis experiment. The present synthetic cellulose was converted to the corresponding triacetate whose molecular weight was at least 6.3 X 10(3) (degree of polymerization (DP) greater-than-or-equal-to 22). X-ray as well as C-13 NMR analyses showed that its crystal structure is of type II with high crystallinity. Under reaction conditions of a higher substrate concentration or higher acetonitrile concentration, water-soluble cellooligosaccharides (DP less-than-or-equal-to 8) were produced predominantly.