Bacterial Cellulose Production and Its Structural Characterization

Abstract

Bacterial cellulose (BC) is an extracellular biopolymer of Acetobacter xylinum, which is now known as Komagataeibacter xylinus. The polymer can be characterized as having outstanding purity, lacking lignin and hemicellulose, while exhibiting high crystallinity, superior mechanical strength, and a distinctive three-dimensional nanofibrillar network compared to plant cellulose. In the current study, BC was grown by inoculating a native isolate of K. xylinus in Hestrin–Schramm (HS) medium and incubating without stirring at 30°C over a period of 7 to 10 days. The gelatinous pellicle was created on the air-liquid interface due to the biosynthesis of bacteria.

The collected pellicles underwent an alkaline purification procedure in order to remove the rest of the bacterial cells and medium constituents. Purification was done by placing the sample in 0.5N sodium hydroxide (NaOH) then washing the sample with distilled water several times until a neutral pH was obtained. This procedure ensured the production of high-purity BC membranes.

Structural characterization was done to prove the successful synthesis of BC. The analysis by Fourier Transform Infrared Spectroscopy (FTIR) showed the typical cellulose functional groups (hydroxyl (-OH) and glycosidic (C-O-C) bonds) which are associated with high-purity cellulose. Scanning Electron Microscopy (SEM) showed a dense, interconnected nanofibrillar network with a large surface area, indicative of well-formed BC. Taken together, the findings indicate that high-quality bacterial cellulose could be effectively produced and purified within the local laboratory setting using cost-effective measures, which explains why this bacterial cellulose could be used in environmental cleanup and adsorption research.