[(1->4)-beta-D-glucosyl](n) + UDP-alpha-D-glucose = [(1->4)-beta-D-glucosyl](n+1) + H(+) + UDP Glycan metabolism; bacterial cellulose biosynthesis. There are two conserved domains in the globular part of the catalytic subunit: the N-terminal domain (domain A) contains the conserved DXD motif and is possibly involved in catalysis and substrate binding. The C-terminal domain (domain B) contains the QXXRW motif and is present only in processive glycosyl transferases. It could be involved in the processivity function of the enzyme, possibly required for holding the growing glycan chain in the active site. In the N-terminal section; belongs to the glycosyltransferase 2 family. In the C-terminal section; belongs to the AcsB/BcsB family.