| Full text | |
| Author(s): |
Luque Castellane, Tereza Cristina
[1]
;
Machado Bueno Otoboni, Alda Maria
[2]
;
de Macedo Lemos, Eliana Gertrudes
[1]
Total Authors: 3
|
| Affiliation: | [1] Univ Estadual Paulista, Fac Ciencias Agr & Vet, Dept Tecnol, Lab Bioquim Microrganismos & Plantas, Sao Paulo - Brazil
[2] Fac Tecnol Marilia, Sao Paulo - Brazil
Total Affiliations: 2
|
| Document type: | Journal article |
| Source: | Revista Brasileira de Ciência do Solo; v. 39, n. 6, p. 1566-1575, NOV-DEC 2015. |
| Web of Science Citations: | 9 |
| Abstract | |
ABSTRACT Increasing attention has been given, over the past decades, to the production of exopolysaccharides (EPS) from rhizobia, due to their various biotechnological applications. Overall characterization of biopolymers involves evaluation of their chemical, physical, and biological properties; this evaluation is a key factor in understanding their behavior in different environments, which enables researchers to foresee their potential applications. Our focus was to study the EPS produced by Mesorhizobium huakuii LMG14107, M. loti LMG6125, M. plurifarium LMG11892,Rhizobium giardini bv. giardiniH152T, R. mongolense LMG19141, andSinorhizobium (= Ensifer)kostiense LMG19227 in a RDM medium with glycerol as a carbon source. These biopolymers were isolated and characterized by reversed-phase high-performance liquid chromatography (RP-HPLC), Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR) spectroscopies. Maximum exopolysaccharide production was 3.10, 2.72, and 2.50 g L-1for the strains LMG6125, LMG19227, and LMG19141, respectively. The purified EPS revealed prominent functional reactive groups, such as hydroxyl and carboxylic, which correspond to a typical heteropolysaccharide. The EPS are composed primarily of galactose and glucose. Minor components found were rhamnose, glucuronic acid, and galacturonic acid. Indeed, from the results of techniques applied in this study, it can be noted that the EPS are species-specific heteropolysaccharide polymers composed of common sugars that are substituted by non-carbohydrate moieties. In addition, analysis of these results indicates that rhizobial EPS can be classified into five groups based on ester type, as determined from the 13C NMR spectra. Knowledge of the EPS composition now facilitates further investigations relating polysaccharide structure and dynamics to rheological properties. (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 |