Abstract:
Recent advances in the field of biomaterials indicate the significance and potential of various microbial polysaccharides in the development of novel classes of materials. Among them, bacterial cellulose, a polymer synthesized in abundance by Acetobacter xylinum, show vast potential to be used as a membrane, as a wound healing system, as electronic paper or as a food matrix. Bacterial cellulose, while chemically the same as plant cellulose is entirely free of lignin and hemicellulose. It displays several unique properties such as high mechanical strength, high water absorption capacity, high crystallinity and a highly pure nano-fibre network structure. Bacterial cellulose can be produced in a static fermentation system using coconut water as the main substrate medium. Sri Lanka has the potential to make bacterial cellulose using coconut water which is a waste product in the desiccated coconut industry. In this study, bacterial cellulose films were prepared by static fermentation of coconut water inoculated with Acetobacter xylinum. Fourier transform infrared spectroscopy on biosynthesized bacterial cellulose confirmed the chemical bond structure to be similar to cellulose. Scanning Electron Microscope images of dried films showed the nano size and net work structure of the cellulose fibrils. Further, bacterial cellulose films with moisture contents from 5 – 25 % (wet basis) had characteristic differences in their tensile properties. The tensile stress values of bacterial cellulose tend to increase whereas tensile strains tend to decrease with the decrease of moisture content of the films. Thereby, Young’s modulus values showed an increasing trend from 32 MPa – 539 MPa with moisture reduction. These investigations proved the ability to produce cellulose based biomaterial consisting nano-scale fibre structure with considerable strength at low cost from a native raw material like coconut water.