Rheological and Thermal Properties of Levan from Bacillus mojavensis

Abstract

Media composition and culture conditions for levan production by Bacillus mojavensis were optimized using Plackett-Burman and Box-Behnken designs. The decomposition of levan revealed an optimal temperature of 228°C, an endothermic peak at 216.58°C and a melting enthalpy of 49.28 J/g. The rheological parameters of the aqueous solutions from BM-levan were determined according to temperature and concentration. The solutions were Newtonian at low concentrations and shear thinning occurred at higher concentrations. Moreover, higher temperature increased pseudoplastic behavior. BMlevan dispersions at 8% and 10% w/v accentuated the gel-like behavior and the viscosity of the levan dispersion; while the visual aspect turned similar to milk. Results showed that BM-levan exhibited no hemolytic activity towards human erythrocytes. These results plead in favor of the suitability of BM-levan as an additive for the processing of several functional foods.

Production and characterization of levan by <i>Bacillus siamensis</i> at flask and bioreactor

“…In a previous study, the thermal properties of levan from Bacillus mojavensis were observed using thermogravimetric analysis (TGA). The amount of levan decreased at the temperature range 205-300 ℃, and the decomposition temperature was 228 ℃ (Haddar et al, 2022). The results of TGA could explain the decrease in levan levels at high temperatures in this study.…”