Abstract Gluconacetobacter hansenii PJK, a cellulose producing bacterium recently isolated from the rotten apples, produced fair amounts of the water-soluble polysaccharides (WSPS). WSPS were studied for their monosaccharides composition after acid hydrolysis, which revealed that the hydrolysates consist only of one sugar, glucuronic acid. The structure of the WSPS was investigated using various spectroscopic techniques including FT-IR, MALDI-TOF MS and 1H, and 13C NMR. These studies revealed that the product is a mixture of oligomers with the α-glucuronic acid as building blocks. The possible structure of the major oligosaccharide in the mixture has been deduced.