Isolation and identification of a bacterial cellulose synthesizing strain from kombucha in different conditions: Gluconacetobacter xylinus ZHCJ618.

A bacterial cellulose (BC) synthesizing strain (Gluconacetobacter xylinus ZHCJ618) was isolated from kombucha and selected as the species for commercial applications owing to its high phenotypic stability and sustainable production capacity of 7.56 ± 0.57 g/L under static culturing conditions and 8.31 ± 0.79 g/L under shaking conditions. The morphological, physiological and biochemical characteristics of the strain were similar to those of Gluconacetobacter genus. The 16S rDNA sequence homologies with G. xylinus NCIB 11664 reached 99%, showing that the isolated strain can be identified as G. xylinus. The material properties of BC were studied by fourier transform infrared spectroscopy, scanning electronic microscopy, X-ray diffraction, thermogravimetric analysis, and tensile test. The results showed that BC synthesized under static conditions exhibited stronger tear strength, higher crystallinity, superior waterhold and rehydration rate than BC synthesized under shaking conditions.