Fabrication and Characterization of Bio-Based Aerogels Derived from Bacillus amyloliquefaciens SQ-2...

Aerogels derived from microbial exopolysaccharides are useful in the food, pharmaceutical, and environmental sectors, but their application in anticancer therapy is constrained by inadequate characterization, especially regarding effects on normal cells. This study used ethanol precipitation and trichloroacetic acid deproteinization to extract crude exopolysaccharide from the fermentation broth of Bacillus amyloliquefaciens SQ-2. The pure fraction, EPS-3791, was obtained using Sephadex G-100 gel filtration chromatography and DEAE cellulose ion exchange. The weight-average molecular weight of EPS-3791 was 64.4 kDa. Monosaccharide analysis indicated fructan as the dominant component, which was consistent with the results of methylation analysis and NMR spectroscopy, confirming that EPS-3791 is a fructan mainly linked by →1)-Fruf-(2→bonds. UV scanning indicated high purity. FTIR analysis revealed functional groups including hydroxyl, carbonyl, and C-O-C groups. EPS-3791 exhibited a porous three-dimensional network morphology by SEM, with a decomposition temperature of 191.61 °C by TGA. Additionally, aerogels were prepared by freeze drying. EPS-3791 aerogels demonstrated minimal cytotoxicity to normal L929 cells while inhibiting the growth of human lung cancer A549, breast cancer MCF-7, and cervical cancer HeLa cells in a dose-dependent manner. Scratch wound healing experiments revealed that EPS-3791 aerogels hindered HeLa cell migration while promoting L929 wound closure. These findings identify EPS-3791 as a fructan-type exopolysaccharide aerogel with specific anticancer properties.