Two new exopolysaccharides from a thermophilic bacterium Geobacillus sp. WSUCF1: Characterization and bioactivities

The production, characterization and bioactivities of exopolysaccharides (EPSs) from a thermophilic bacterium Geobacillus sp. strain WSUCF1 were investigated. Using glucose as a carbon source 525.7 mg/L of exoproduct were produced in a 40-L bioreactor at 60 degrees C. Two purified EPSs were obtained: EPS-1 was a glucomannan containing mannose and glucose in a molar ratio of 1:0.21, while EPS-2 was composed of mannan only. The molecular weights of both EPSs were estimated to be approximately 1000 kDa, their FTIR and NMR spectra indicated the presence of alpha-type glycosidic bonds in a linear structure, and XRD analysis indicated a low degree of crystallinity of 0.11 (EPS-1) and 0.27 (EPS-2). EPS-1 and EPS-2 demonstrated high degradation temperatures of 319 degrees C and 314 degrees C, respectively, and non-cytotoxicity to HEK-293 cells at 2 and 3 mg/mL, respectively. In addition, both showed antioxidant activities. EPSs from strain WSUCF1 may expand the applications of microorganisms isolated from extreme environments and provide a valuable resource for exploitation in biomedical fields such as drug delivery carriers.

Automated summary

The study investigated the production, characterization, and bioactivities of exopolysaccharides (EPSs) from a thermophilic bacterium Geobacillus sp. strain WSUCF1, resulting in two purified EPSs with potential applications in biomedical fields such as drug delivery carriers. EPS-1 and EPS-2 demonstrated high degradation temperatures and antioxidant activities, showing promising prospects for further exploitation.