Study of levan productivity from Bacillus subtilis Natto by surface response methodology and its antitumor activity against HepG2 cells using metabolomic approach.

Levan productivity of Bacillus subtilis Natto was evaluated in submerged culture varying the pH, temperature and culture time, using factorial design and response surface methodology. The characterization of levan molecular weight was performed by HPSEC and its antitumor activity against HepG2 cells using metabolomic approach was also evaluated. At first, the variables investigated, as well as their interactions, demonstrated significant effect. Further, a second design using the same variables at different levels was developed. Thus, according to the model, an optimized value corresponding to 5.82 g.L⁻¹.h⁻¹ was achieved at pH 8, 39.5°C in 21 hours, the highest value reported so far. After analysis by HPSEC, two molecular weights were obtained corresponding to 72.37 and 4146 kDa. The levan promoted an increase of acetate, alanine, lactate and phosphocreatine in HepG2 cells suggesting an alteration in the bioenergetics pathways and cellular homeostasis by intracellular accumulation of lactate, justifying its antitumor activity.

Levan as a new additive for colon-specific films: a new approach in the use of exopolysaccharides in time-dependent free films (Aminoalkyl Methacrylate Copolymer RS).

Time-dependent films, augmented with prebiotics, offer potential strategy for colon-specific controlled drug release. In this study, we produced films containing levan (L) and Aminoalkyl Methacrylate Copolymer RS (ER). Free films of ER combined with levan were produced by the casting process and characterized by the mobility of the polymeric matrix, hydration, differential scanning calorimetry (DSC) and thermogravimetry (TGA). The results of this study suggest that the exopolysaccharide levan can be used in combination with ER for colon specific materials. No evidence of incompatibilities between the levan and the synthetic polymer were detected, and levan improved the mobility of the polymeric matrix and the hydrophilicity of the system. Levan may have positively altered the density of the polymeric matrix, as visualized by thermal characterization. The endothermic decomposition peak was shifted with increasing amounts of levan. This new barrier polymer utilized a combination of time-dependent enzymatic mechanisms and can be considered promising for use in the coating of solid oral drugs for specific release.