PelX is a UDP--acetylglucosamine C4-epimerase involved in Pel polysaccharide-dependent biofilm formation.

Pel is a GalNAc-rich bacterial polysaccharide that contributes to the structure and function of biofilms. The operon is highly conserved among diverse bacterial species, and Pel may therefore be a widespread biofilm determinant. Previous annotation of gene clusters has helped us identify an additional gene, , that is present adjacent to in >100 different bacterial species.