Glucuronan is a polysaccharide composed of β-(1,4)-linkedd-glucuronic acids having intrinsic properties and biological activities recoverable in many fields of application. Currently, the description ofSinorhyzobium melilotiM5N1CS mutant bacterial strain as the sole source of glucuronan makes it relevant to the exploration of new microorganisms producing glucuronan. In this study, thePeteryoungia rosettifformansstrain (Rhizobia), was identified as a wild producer of an exopolysaccharide (RhrBR46) related to glucuronan. Structural and biochemical features, using colorimetric assays, Fourier infrared spectroscopy, nuclear magnetic resonance, high pressure size exclusion chromatography coupled to multi-angle light laser scattering, and enzymatic assays allowed the characterization of a polyglucuronic acid, having a molecular mass (Mw¯) of 1.85 × 105Da, and being partiallyO-acetylated atC-2 and/orC-3 positions. The concentration of Mg2+ions in the cultivation medium has been shown to impact the structure of RhrBR46, by reducing drastically itsMw¯(73%) and increasing its DA (10%). Comparative structural analyses between RhrBR46 and the glucuronan fromSinorhyzobium melilotiM5N1CS strain revealed differences in terms of molecular weight, degree of acetylation (DA), and the distribution of acetylation pattern. These structural divergences of RhrBR46 might contribute to singular properties or biological activities of RhrBR46, offering new perspectives of application.