Rheological, antibacterial, antioxidant properties of D-mannitol-induced highly viscous succinoglycans produced by Sinorhizobium meliloti Rm 1021

Highly viscous microbial polysaccharide is one of the essential resources for various industries as a novel rheological agent to replace synthetic chemicals. Rheological properties of D-mannitol-induced highly viscous succinoglycan (SG) produced by Sinorhizobium meliloti Rm 1021 have been investigated. When the concentration of D-mannitol as a carbon source in the GMS medium increased, SG exhibited a higher degree of succinylation. When the concentration of D-mannitol was increased to 10 times in the GMS medium, the viscosity of 1 wt% highly succinyl-substituted SG remarkably increased up to 7.726 Pa s, about 24.75 times higher than normal SG. As the degree of succinylation increased, the thermal stability and rheological properties of SG were proportionally improved, showing an increased energy storage capacity with a higher G′ than G″ up to 90 °C. This highly succinyl-substituted SG also showed the enhanced both antibacterial effects against E. coli and S. aureus and radical scavenging activities against DPPH and hydroxyl radical. [Display omitted] •Highly succinylated succinoglycans were produced by high D-mannitol concentration in medium from S. meliloti Rm1021.•When D-mannitol in the medium was increased, the viscosity of succinoglycan with a high succinyl group increased.•The thermal stability and rheological properties of highly succinylated succinoglycan were enhanced.•The antibacterial and antioxidant properties of succinoglycan with a high degree of succinyl group substitution are increased.