Pseudomonas stutzeriOXI is a Gram-negative microorgan-ism able to grow in media containing aromatic hydrocar-bons. A novel lipo-oligosaccharide fromP. stutzeriOX1 was isolated and characterized. For the first time, the pres-ence of two moieties of 4,6-O-(1-carboxy)-ethylidene resi-dues (pyruvic acid) was identified in a core region; these two residues were found to possess different absolute configur-ation. The structure of the oligosaccharide backbone was determined using either alkaline or acid hydrolysis. .
