2.3 Bacterial cellulose yield
The synthesized cellulose was separated from the medium by filtration and boiled in 1% sodium hydroxide solution for 30 min to remove cells and medium embedded in the cellulose material,then rinsed 3 days with deionized water to reach neutral pH (Yanet al., 2008). The BC samples were freeze-dried to obtain dry mate-rial. Bacterial cellulose yield was calculated from the dry weight ofpurified cellulose.2.4. Scanning electron microscopyThe freeze-dried samples were coated with gold (E-1045,Hitachi, Tokyo, Japan). Analysis of the structure of the BC was per-formed by using a Field-Emission Scanning Electron Microscope(FESEM) (NVision 40, ZEIS) at 25 kV. Images were taken with 2000×FESEM micrograph magnifications.2.5. X-ray diffraction (XRD)XRD was