When using bacterial cellulose (BC) hydrogel for preparing composites with TEOS, the BC hydrogel was immersed into 10 and 20% aqueous TEOS dispersions delivering silica deposited on BC microfibrils via silanol. The TGA measurements indicated that thermal degradation occurs at 320 °C and after 500 °C the silica content was 43 wt % of the hybrid composite prepared with 20% TEOS. Those TGA curves look very similar to those of CP2 and CP4 of this work .