A screening of 27 collection strains and 135 strains isolated from carbohydrate rich waste materials permitted the selection of 13 strains which produced more 6-deoxyhexose-containing polysaccharides than a reference strain: Acinetobacter calcoaceticus BD 413 (ATCC 33304). The most productive strain identified as Klebsiella sp. excreted 1.6 g of rhamnose per liter of culture medium after improvement of certain culture conditions. The Klebsiella polysaccharide was recovered by precipitation which acetone and hydrolyzed. Rhamnose was separated by chromatography on Dowex 1 × 4 in borate buffer. Our study shows that sewage sludge is a good source of polysaccharide producers and that the use of hydrocarbon in selective medium and of a high carbon-nitrogen ratio promotes their development.