Chemical and rheological properties of exopolysaccharides produced by four isolates of rhizobia

Author(s)

Moretto, Cristiane ^[1] ; Luque Castellane, Tereza Cristina ^[1] ; Lopes, Erica Mendes ^[1] ; Omori, Wellington Pine ^[1] ; Sacco, Lais Postai ^[1] ; de Macedo Lemos, Eliana Gertrudes ^[1]

Affiliation

^[1] UNESP Univ Estadual Paulista, Fac Ciencias Agr & Vet, Dept Tecnol, BR-14884900 Jaboticabal, SP - Brazil

• Document type: Journal article
• Source: International Journal of Biological Macromolecules; v. 81, p. 291-298, NOV 2015.
• Web of Science Citations: 9

Abstract

The rheological, physicochemical properties, emulsification and stability of exopolysaccharides (EPSs) from four rhizobia isolates (LBMP-C01, LBMP-CO2, LBMP-CO3 and LBMP-C04) were studied. The EPS yields of isolates under these experimental conditions were in the range of 1.5-6.63 g L-1. The LEMP-C04 isolate, which presented the highest EPS production (6.63 g L-1), was isolated from Arachis pintoi and was identified as a Rhizotrium sp. strain that could be explored as a possible potential source for the production of extracellular heteropolysaccharides. All polymers showed a pseudoplastic non-Newtonian fluid behavior or shear thinning property in aqueous solutions. Among the four EPS tested against hydrocarbons, EPS LBMP-C01 was found to be more effective against hexane, olive and soybean oils (89.94%, 82.75% and 81.15%, respectively). Importantly, we found that changes in pH (2-11) and salinity (0-30%) influenced the emulsification of diesel oil by the EPSs. EPSLBMP-C04 presented optimal emulsification capacity at pH 10 (E-24 = 53%) and 30% salinity (E-24 = 27%). These findings contribute to the understanding of the influence of the chemical composition, physical properties and biotechnology applications of rhizobial EPS solutions their bioemulsifying properties. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 10/11957-6 - Construction of mutant gene exoz involved in the synthesis of repeating subunits of EPS and the genes phbA, phbB and phbC responsible for the synthesis of PHB in Rhizobium tropici SEMIA 4080
• Grantee: Eliana Gertrudes de Macedo Lemos
• Support Opportunities: Regular Research Grants