Bacterial Cellulose Production, Characterization, and Its Use as a Membrane Filter for Microorganism

Abstract

The aim of this study was to investigate the usability of bacterial cellulose (BC) produced by Gluconacetobacter xylinus NRRL B-759 (Komagataeibacter xylinus) as a membrane filter and to determine the shortest incubation time for obtaining the BC membrane with an effective removal capacity. BC production of this bacterium was found to be dependent on incubation time (day), and the properties of the membranes produced on each day were then examined in detail. BC formed on the third day showed a suitable peak structure and ideal formation of the cellulose structure, as determined by FTIR and X-ray analyses, respectively. SEM analysis also confirmed that the membrane structure obtained on the third day was optimal. All membranes produced from the second day onward exhibited sufficient mechanical properties. TGA and DSC analyses showed that the BC membrane structures were thermally stable at approximately 200 °C and exhibited suitable flexibility at 20 °C. To evaluate the potential of BC membranes as filters, the prepared Escherichia coli and Staphylococcus aureus suspensions were filtered through the third-day BC membranes under sterile conditions. No bacteria were detected in the filtrate, indicating the effective microorganism retention. Reusability tests revealed that these membranes could be repeatedly used in the filtration process. SEM, EDX analyses, and surface elemental mapping of the membranes used for filtration of E. coli and S. aureus showed that the bacterial cells on the membrane surface and unlike the pure membranes (the membranes without filtration) exhibited the presence of nitrogen, phosphorus, and sulfur peaks. The results of this study demonstrated that BC membranes could be used effectively in microorganism-filtration applications. The BC membrane may also serve as an effective biologic material for filtration of various pollutants.