Conversion of capsular polysaccharide, involved in pellicle formation, to extracellular polysaccharide by galE deletion in Acetobacter tropicalis.

Acetobacter tropicalis SKU1100 produces a pellicle-forming capsular polysaccharide (CPS), consisting of galactose, glucose, and rhamnose. We cloned the galE gene, a UDP-galactose synthesis gene, from A. tropicalis SKU1100 by PCR. A galE-disruptant was prepared and found not to produce CPS and thus not to form a pellicle under the static condition. Instead, the DeltagalE mutant secreted an extracellular polysaccharide (EPS), which was purified and found to have a unique character, different from the original CPS.