ABSTRACT

The control of cellulose I microfibril formation by liv ing organisms has been of intense interest ever since such microfibrils were visual­ ized in shadowed specimens in the electron microscope (1 ,2 ) . Sub - sequent microscopic and crystallographic examination of cellulose microfibrils from a variety of organisms demonstrated that the width and crystallite size of microfibrils varied greatly between organisms and even within organisms at different stages of development (3 ) . Furthermore, the crystalline polymorph formed predominantly in na­ tu re , cellulose I , is different from cellulose I I , which is formed when cellulose I is swollen in alkali or precipitated from solution (4 ) . As long as four decades ago, Frey-Wyssling et al. proposed that the uniformity of microfibril size in plant and bacterial cellulose TTspeaks for a control of cellulose crystallization by the living cytoplasmrt (2) and R§nby argued, based on the preferential formation of cellulose I I under acellular conditions, that cellulose I formed not from glucan chains crystallizing acellularly but rather "from chains under the in ­ fluence of a specific enzyme system or by direct synthesis in the cell" (5 ) .