Production and characterization of Komagataeibacter xylinus SGP8 nanocellulose and its calcite based composite for removal of Cd ions

In the present study, fermentative production of bacterial nanocellulose (BNC) by using Komagataeibacter xylinus strain SGP8 and characterization of nanocellulose is presented. The bacterium was able to produce 1.82 g L −1 of cellulose in the form of pellicle in standard Hestrin-Schramn (HS) medium. The morpho-structural characterization of the BNC using scanning electron microscopy (SEM) and X-ray diffraction (XRD) studies, respectively revealed nanofibrillar structure and high crystallinity index (~86%). The thermogravimetric analysis (TGA) showed the stability of BNC up to 280 °C, further rise in temperature to 350 °C results in depolymerization of the sample. In order to show the applicability of produced BNC, it was modified first using calcite (CaCO 3 ) and thereafter characterized using SEM, XRD, FTIR, and TGA studies. The BNC-CaCO 3 composites as a sorbent resulted in >99% removal of initial 10 mg L −1 of Cd (II) at pH 5, 7 and 9 after 12 h of treatment. Moreover, the composite was also found to be competent in removing high concentrations of Cd (25 and 50 mg L −1 ) from the solution (69–70%). Overall, the above results suggest that cellulose produced by K. xylinus strain SGP8 showed excellent material properties, and modified BNC (BNC-CaCO 3 composite) could effectively be used for remediation of toxic levels of Cd from the contaminated system.