Abstract: The present invention comprises a biologically pure culture of a cellulose-producing microorganism, preferably a prokaryote. This cellulose-producing microorganism is capable, during fermentation in an aqueous nutrient medium containing assimilable sources of carbon, nitrogen and inorganic substances, of reversal of direction of cellulose ribbon extrusion. This reversal of direction of cellulose ribbon extrusion results on the cellulose-producing microorganism shuttling, at least periodically, first in one direction and then in the other direction along a length of an earlier-deposited cellulose ribbon to add another cellulose ribbon thereto and produce a cellulose ribbon-bundle having a width of at least two cellulose ribbons.The cellulose-producing microorganism of the present invention may be of the genus Acetobacter, Agrobacterium, Rhizobium, Pseudomonas or Alcaligenes, preferably of the genus Acetobacter and more preferably of the species Acetobacter xylinum or Acetobacter pasteurianus.