Production and Characterization of Bacterial Cellulose from Komagataeibacter xylinus

Abstract

Eight isolates previously isolated from rhizoplane of sugarcane roots grown in Aswan Governorate, Egypt and biochemically identified as Gluconacetobacter spp. were used to evaluate their cellulose production ability. All isolates were subjected to a set of tests that proved their efficiency in producing cellulose i.e. formation of white gelatinous pellicle, absence of precipitate, clear zone formation and yield of bacterial cellulose (BC).The results cleared that the isolate SuGu9 was the potent one that produced 2.7 g/L BC. The isolate was identified using 16S rRNA technique and found to be Komagataeibacter xylinus PP431972. This bacterium was known as a modeling microorganism for cellulose production. The morphological, physiochemical and thermal properties of BC produced were also estimated. The BC appeared as a rough surface related to fibrous structure of cellulose by scanning electron microscopy (SEM) as well as SEM pattern appeared as longitudinal fibers. The Fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD) graphs for the BC were typical for BC of K. xylinus with 23% crystallinity. For the thermal stability, thermogravimetric analysis (TGA) curves showed the percentage of weight loss for BC which gradually increased with the increasing of temperature and maximum loss of weight (65.35%) was recorded at 577.7°C. Moreover, derivative thermogravimetry (DTG) curve shows that the maximum rate of this transformation (641.0 μg/min.) occurs at temperature of approximately 297.6°C. While differential scanning colorimetry (DSC) curves indicated that glass transition temperature (Tg) of the BC films was found to be 174.9°C.