Resumo

MONTEIRO, Nilson Kobori et al. Chemical characterization of the gels produced by the diazotrophic bacteria Rhizobium tropici and Mesorhizobium sp.. Quím. Nova [online]. 2012, vol.35, n.4, pp. 705-708. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40422012000400009.

The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPS_RT) and Mesorhizobium sp (EPS_MR) are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose (~ 1%). Chemical analysis showed the presence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPS_RT and EPS_MR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, ¹H and ¹³C-NMR.

Palavras-chave : acid exopolysaccharide; Rhizobium tropici; Mesorhizobium sp.