completely removed by repeated washings with water and the
matrix used for immobilization of bacteria. Although many other
microorganisms produce cellulose, A. xylinum is one of the most
efficient producers. Cellulose is an unbranched polymer of b (1, 4)
linked glucopyranose residues and the chains aggregate to form
subfibrils which have a width of 1.5 nm. These subfibrils are crystallized
into microfibrils, bundles and later to ribbons (Jonas &
Farah, 1998). The overlapping and inter twisted cellulose ribbons
forming parallel but disorganized strands have the potential to hold
many bacteria in the spaces (Fig. 2A) and also on the surface
(Fig. 2B).
Fig. 1B and C show the calcium alginate capsules and skim milk
matrix respectively used in the present study.
As a representative example L. delbrueckii NCIM 2025 cells
immobilized on bacterial cellulose are shown in Fig. 2A and B while
Fig. 2C shows the same bacteria encapsulated in calcium alginate.